Controling Holiday Lights
ANDREW GREGORY
because we have so many lights. We put on a good show for Halloween and
right after I start putting up 27,000 Christmas lights. I have been
increasing the complexity of our display every year with some animations and
flashing lights but it is vary difficult and time consuming using Activehome
and the X-10 hardware. I would like to take it to the next level this year
but can not find any good X-10 software to use.
I have been looking at the software offerings and am having a hard time
finding something to help me to the next level. I have looked at allot of
the free stuff and found most can not be programmed faster than 1 sec. not
fast enough for sequencing dancing lights and still time consuming to
program. Looking at allot of the paid programs I can not determine if it
will help without buying them all.
I am looking for a X-10 control program that is easy to program sequences
down to a tenth of a second to do some dancing lights in my 45 foot
charismas tree this year. Can anybody tell me if the software they are using
mite be able to help or should I scrap the hole idea and us some thing like
Weed Techs digital I/O board and hope to find some good control software for
it to do dancing lights.
The ultimate for me would be a program that would run off an excel spread
sheet where if a box is filled to would turn on an output and stay on if
more boxes where filled and then off at the next clear box running over
time.
I have seen all the ready made charismas light hardware and software but I
do not have the time or money to go that route and was hoping to save some
of my investment in X-10 that has served me well all these years leading up
to this point.
Thanks Andy
Jeff Volp
messages, such as A-1, A-ON. With the 3 cycle intermessage gap, a complete
command takes 47 cycles of 60Hz. Another 3 cycle gap is needed before
another message can be sent.
I would use a PC controlling a bunch of solid state relays. Years ago I
built custom factory automation equipment using DOS era PCs, and even that
would be capable of doing what you want.
Jeff
"ANDREW GREGORY" <4py...@verizon.net> wrote in message
news:onBYg.1136$Dg5.1061@trndny09...
Michelle P
sylvan butler
> I am looking for a X-10 control program that is easy to program sequences
> down to a tenth of a second to do some dancing lights in my 45 foot
Not going to happen. X10 is too slow.
> I have seen all the ready made charismas light hardware and software but I
> do not have the time or money to go that route and was hoping to save some
You can save time by spending money. Or save money by spending time.
You will need to determine where on that scale you need to be.
> of my investment in X-10 that has served me well all these years leading up
You can use X10 for the slow stuff (1sec or slower) and start adding
faster stuff for the faster effects.
As for software... I do my own. Sorry.
You can find more software and hardware info at sites such as
http://computerchristmas.com/ (highly recommended) See their "how-to"
and forum sections.
If you aren't comfortable doing 120vAC component wiring, controllers can
be purchased, but they aren't what I would call cheap.
Long and boring hardware details follow...
-----------
If you are up to doing 120vAC component wiring, you can save money by
spending time. You can build controllers using a solid-state relay
(SSR) controlled from a parallel port and switching a 120v circuit. Or
for cheaper you can build your own SSR using an opto-coupler (to protect
the parallel port) and a triac. I have been able to buy SSRs cheap
enough on the surplus market that I haven't bothered with triac
circuits. For example, this looks like it would work well:
(http://www.allelectronics.com/ then Relays then Solid-State)
home page at:
http://www.crydom.com/products/productFamily.aspx?id=22
detail spec:
http://www.crydom.com/userResources/productFamilies/22/crydom_ez.pdf
The 3-15vdc control input means most PC parallel ports should be able to
control the relay. The 240vac at up to 18amps means you can switch
about as many lights as you would ever put on one circuit. (Probably
you want to keep the number under 50%, or less than 9 amps because these
relays will need a heat sink to keep them cool when running large loads
or high ambient temperatures.) That particular relay is "zero crossing"
which minimizes the interferance to TV and radio reception, but also
means you cannot make a light dimmer or ramp brightness up or down as
well as a "random" switching relay. At under $10/ea buying a dozen is
maybe half of retail price. (A typical PC parallel port can typically
control 12 such relays.) Sometimes you can find even better deals.
AllElectronics also lists a 1amp SSR for $1.50. that might be enough for
each channel. Can't find good specs on it though. However at that
price I'm tempted to buy a dozen just to play with. Small enough to
mount right on the outlet and probably easy to fit four of them into a
four-gang metal box with two duplex outlets...
I build my controllers in sets of four (four independently switched
outlets in a metal box) with a short 120vAC plug for power and an RJ45
(8 conductor "network" jack) for control input. (of the 8 control
wires, four (two pair) control the circuits, two (one pair) provide
ground, and the last two (one pair) provide power (which these simple
relay boxes do not need or use). I use the standard power-over-ethernet
wiring for the power distribution and use what would normally be
"ethernet" wires for the control signals. Then I can use up to three
such boxes per parallel port. Because I use standard jacks I can use
whatever off-the-shelf patch cord I want between my parallel port
adapter and the box. I've used up to 100ft patch with no problems.
I've toyed with the idea of building an expansion for the parallel port
to control more boxes, but it seems too tedious so I haven't.
-----------
Anybody have a source for cheap PCI parallel port cards (e.g. four
parallel ports on one card)?
sdb
--
Wanted: Omnibook 800 & accessories, cheap, working or not
sdbuse1 on mailhost bigfoot.com
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejam1g.thm.Z...@sdba64.internal>:
>Anybody have a source for cheap PCI parallel port cards (e.g. four
>parallel ports on one card)?
Never seen such a beast.
A venerable and still current solution to the need for multiple digital (TTL)
input-output (I/O) are ISA- and PCI-bus cards based on the 8255 Programmable
Input Output (PIO) IC from the 8080 chip family which predated the original
8088 IBM PC.
Google 8255 PIO for hardware, drivers and software ideas.
There are typically many for sale at eBay for nickels on the dollar.
Business & Industrial > Industrial Electrical & Test > Test Equipment > Card
Based (VXI/PXI/PCI)
The current National Instruments DIO cards are the PCI-6503 (24 TTL I/O),
PCI-DIO-96 (96 TTL I/O) and PCI- 6257 (48 I/O, optically isolated with 120ma
drive).
(I'll be having an internet porch sale in a couple of weeks and will have a
pile of these and related instrumentation and HA items for sale/swap.)
HTH ... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote in message
<a7kcj2d5csnnucnn9...@4ax.com>:
>The current National Instruments DIO cards are the PCI-6503 (24 TTL I/O),
>PCI-DIO-96 (96 TTL I/O) and PCI- 6257 (48 I/O, optically isolated with 120ma
>drive).
oops. Its PCI-6527, not 6257
... Marc
John Haskey
sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>
>Anybody have a source for cheap PCI parallel port cards (e.g. four
>parallel ports on one card)?
Why not use MIDI? There's a very inexpensive controller that you could
build (midibox.org) that will give 128 inputs and outputs. More can
be added by just daisy chaining more controllers on the MIDI cable.
You can program with free MIDI sequencing software. You'd also have
the capability of syncing easily to a sound track!
---john.
Robert L Bass
> build (midibox.org) that will give 128 inputs and outputs. More can
> be added by just daisy chaining more controllers on the MIDI cable.
> You can program with free MIDI sequencing software. You'd also have
> the capability of syncing easily to a sound track!
Good point, John. One of my favorite Christmas displays is about three miles down Proctor Rd from my home in Sarasota. There are
something like 400,000 (really) lights on all kinds of moving displays. Everything is sequenced to a MIDI soundtrack playing
traditional Christmas hymns through speakers hidden in the trees. The entire theme is really about Christmas -- no Santa and no
reindeer. Every year they add to the display. It's a pretty famous light show, attracting visitors from all over the world every
year. This is a private home, by the way.
--
Regards,
Robert L Bass
=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>
Si Ballenger
>Anybody have a source for cheap PCI parallel port cards (e.g. four
>parallel ports on one card)?
The below board might be better than parallel ports.
sylvan butler
> In article <slrnejam1g.thm.Z...@sdba64.internal>,
> sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>>
>>Anybody have a source for cheap PCI parallel port cards (e.g. four
>>parallel ports on one card)?
>
> Why not use MIDI?
SsssssssLlllllllOoooooooWwwwwwwww
Granted, MIDI is probably 10x the speed (in theory) of X10, but I
haven't seen a complete solution to know what is achievable. And that
still means only about 10 cycles per second (Hertz or Hz), which still
limits you to only basic on/off effects. (Compare to 50-60Hz for a
zero-crossing A.C. relay or way over 1000Hz for a PC parallel port.)
With a direct access binary I/O (eg parallel port or a normal digital
I/O pin of a microcontroller such as PIC) it is trivial to PWM a light
from dark to full on and back to off to create fades. If all I wanted
to do was turn on and off there are innumerable ways, and X10 is darn
effective. But once you add speed into the mix, it changes the problem
dramatically.
As for midibox, it appears to be a midi controller primarily, with some
direct I/O capability included. I don't see the direct applicability
unless I wanted to replace to the PC as a controller, and then I see no
obvious reason to introduce the complexity and delays of MIDI.
sylvan butler
That looks like a nice I/O board. But I'm skeptical of the speed at
which one could arbitrarily change the bits. For example, walking-1 or
walking-0 thru the entire set, or invert all or some arbitrary subset
(xor), and other common effect operations.
Something like these (similar to what Marc pointed out) is more likely
to be fast enough: http://www.futurlec.com/PCI16IO.shtml or
http://www.futurlec.com/PCI8255.shtml That actually looks like a nice
card. Each 8255 is roughly two XT/AT style parallel ports so if it is
designed well, that card might do what I need, and the price isn't too
far out either. Too bad Futurelec doesn't put detailed tech info
online. There's no way I'd be using Windows! Of course, for that price
I could build a PIC based solution and not need a PC at all...
Robert L Bass
>
> SsssssssLlllllllOoooooooWwwwwwwww
The MIDI controlled Christmas lighting display I described earlier sequences hundreds of circuits. Lights and motors switch on and
off, sometimes at blazing speeds, to the tune of the MIDI track. There are several scenes where a series of lighting circuits
flashes on and off at about 10-20 times per second per circuit. Note: I'm guessing as to the rate, but it was way too fast to
count.
> Granted, MIDI is probably 10x the speed
> (in theory) of X10, but I haven't seen a
> complete solution to know what is achievable...
I have and it's pretty darned fast. A group of volunteers starts to build the set each year around the middle of October (it takes
seven weeks to set the whole thing up according to a notice at the entrance to the property). I'll stop by this weekend and ask
which controller they're using. I believe someone said they used Cakewalk software to sequence the system. I'll check on that,
too.
> And that still means only about 10 cycles
> per second (Hertz or Hz), which still limits
> you to only basic on/off effects. (Compare
> to 50-60Hz for a zero-crossing A.C. relay
> or way over 1000Hz for a PC parallel port.)
Controlling holiday lights that should not be much of a limitation.
> With a direct access binary I/O (eg parallel
> port or a normal digital I/O pin of a
> microcontroller such as PIC) it is trivial to
> PWM a light from dark to full on and back
> to off to create fades. If all I wanted to do
> was turn on and off there are innumerable
> ways, and X10 is darn effective. But once
> you add speed into the mix, it changes the
> problem dramatically.
In addition to clunky X10 and faster, more flexible MIDI, there are other options. The DMX-512 protocol is used for modern
theatrical lighting. It's also in use on commercial buildings where its simple topology and reliable performance are important
considerations. One of the regular posters here has even designed a home-use DMX-512 lighting controller. I've used DMX-512
extensively in designing theatrical lighting systems for churches and small auditoriums.
DMX-512 can run up to 512 circuits (hance the name) on a single cable. It's fast enough to run high speed, automated spotlights and
musicians' light shows. Controllers used to be prohibitively expensive for home use. However, over the last few years a number of
companies have come out with PC card-based DMX-512 controllers. Dimmers and dimming "packs" range from a hundred dollars or so to
over $2K, depending on the number of circuits and their ampacity. Homebrew DMX-512 compatible dimmers and relays would be
significantly cheaper, though I couldn't begin to tell you how to build one from scratch.
> As for midibox, it appears to be a midi controller
> primarily, with some direct I/O capability included...
It depends on the box. There are relatively inexpensive, multi-circuit lighting controlers (DJ's use them) that can be controlled
by MIDI, DMX-512 or 0-10 Volts DC. DJ lights can dim and flash on/off as fast as the beat on a MIDI sequencer runs a set of Roland
digital drums. The tempo can be blindingly fast. If you've ever watched a rock concert on stage you've seen MIDI controlled
lighting effects.
> I don't see the direct applicability unless I
> wanted to replace to the PC as a controller,
> and then I see no obvious reason to
> introduce the complexity and delays of MIDI.
It's just one of a number of protocols you can use to control lights. The choice shouldn't be about the protocol so much as the
available hardware and its cost. Any one of a number of protocols can be used effectively for this project. MIDI would work fine
(it's faster than you might realize). That doesn't mean MIDI is best for your application but it's certainly worth investigating
IMO.
sylvan butler
>> and then I see no obvious reason to
>> introduce the complexity and delays of MIDI.
>
> It's just one of a number of protocols you can use to control lights.
> The choice shouldn't be about the protocol so much as the available
> hardware and its cost. Any one of a number of protocols can be used
That's the disconnect.
I'm talking about the hardware, and you are talking about the protocols
to talk to the hardware.
Robert L Bass
>> can use to control lights. The choice
>> shouldn't be about the protocol so much
>> as the available hardware and its cost.
>> Any one of a number of protocols can be
>> used
>
> That's the disconnect.
>
> I'm talking about the hardware, and you are talking about the protocols
> to talk to the hardware.
I don't see why you consider MIDI too slow to accomplish the task. The MIDI protocol isn't inherently slow and the MIDI hardware
I've seen is lightning fast. What is it you'd like to accomplish in terms of holiday lighting that is faster than the system
(hardware, software and protocol together) which I described?
If you're interested in a holiday lighting controller with serious power and speed, I'd be happy to try to get the specs from these
neighbors who built the system. AFAIK, they are using mostly off the shelf components.
John Haskey
sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>On Wed, 18 Oct 2006 23:35:59 +0000 (UTC), John Haskey <jo...@panix.com> wrote:
>> In article <slrnejam1g.thm.Z...@sdba64.internal>,
>> sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>>>
>>>Anybody have a source for cheap PCI parallel port cards (e.g. four
>>>parallel ports on one card)?
>>
>> Why not use MIDI?
>
>SsssssssLlllllllOoooooooWwwwwwwww
Given the solid state relay you reference in the previous post you could
send the MIDI command to turn the light on and off four times (worst case)
in the time it would take the relay to turn on.
>Granted, MIDI is probably 10x the speed (in theory) of X10, but I
>haven't seen a complete solution to know what is achievable. And that
>still means only about 10 cycles per second (Hertz or Hz), which still
>limits you to only basic on/off effects. (Compare to 50-60Hz for a
>zero-crossing A.C. relay or way over 1000Hz for a PC parallel port.)
I agree that the parallel port is much faster but how fast is fast
enough? Your relay is going to take ~8ms to turn on. An incandescent
bulb can take at least 25ms to reach full brightness (often more).
It depends on how many relays you are going to control and that's
pretty limited unless you multiplex your parallel port.
Do whatever works. I think MIDI may be fine in many cases. And it'd
be easy to program given the free software that is available.
---john.
sylvan butler
> sylvan wrote:
>> I'm talking about the hardware, and you are talking about the protocols
>> to talk to the hardware.
>
> I don't see why you consider MIDI too slow to accomplish the task.
I'm wanting the hardware to control TRIAC or SSR switches, eg a parallel
binary I/O port. With that I can turn on and off a light (or anything
else) at a rate over 1000 times per second.
This allows all kinds of creative fades to On, Off, or anywhere in
between at 100% the whim of my self-written software.
MIDI cannot do that and was never intended to do that. MIDI is a
control protocol which is used to tell my hardware what to do. I'm not
interested in another protocol that will tell my hardware what to do. I
am trying to build hardware. :)
> The MIDI protocol isn't inherently slow and the MIDI hardware
MIDI is inherently slow.
MIDI runs at several bytes per second. Each command is a few dozen
bytes. Do the math. It's slow.
Thanks for your offer, but it is the wrong direction for me.
Robert L Bass
Doable with MIDI, DMX-512, 0-10VDC and a few dozen other means.
> eg a parallel binary I/O port. With that I
> can turn on and off a light (or anything
> else) at a rate over 1000 times per second.
Considering the lag time between turning on the power and the filament heating up enough to be seen, why would you care if it can do
1,000 cycles per second?
> This allows all kinds of creative fades to
> On, Off, or anywhere in between at 100%
> the whim of my self-written software.
Yep. I've designed and installed a number of theatrical lighting control systems which would make most home holiday displays pale
by comparison. I can also tell you that there are existing, off-the-shelf solutions which can accomplish what you want to do,
although none issue 1,000 commands per second.
> MIDI cannot do that and was never intended
> to do that. MIDI is a control protocol which
> is used to tell my hardware what to do. I'm
> not interested in another protocol that will
> tell my hardware what to do. I am trying to
> build hardware. :)
Sounds like a fun project. I hope you'll share your experiences as it progresses.
>> The MIDI protocol isn't inherently slow and the MIDI hardware
>
> MIDI is inherently slow.
>
> MIDI runs at several bytes per second. Each command is a few dozen
> bytes. Do the math. It's slow.
You've decided to use another protocol so this is just a discussion -- not me trying to convince you what to use. That said, here's
some info about MIDI. The protocol allows an instrument (or sequencer) to be controlled by "clocks" or "ticks". 48 clocks are sent
per second. Ticks, on the other hand, are sent at a rate of 1 message every 10 mSec. That's only 100 changes per second. Note
that a "change" can be a command such as "Begin fade from scene 125 to 126" or simply, "turn circuit 125 on". Note that while ticks
are intended as a means of keeping things sync'd, it is possible to store a series of commands to build a sequence, then cause them
to execute in order based on tick count.
> Thanks for your offer, but it is the wrong direction for me.
No problem. I look forward to reading about your project (hoping you'll hang around and share what you learn as you go).
Regardless how you choose to execute it, this is the kind of project that interests a lot of regulars here. IN that light, you
might also want to Google the archives of CHA using "Christmas lights" or some such. There have been a number of interesting
threads on the subject every year since I've been posting (and that's a long time) here.
Best of luck.
sylvan butler
> In article <slrnejfnul.uc9.Z...@sdba64.internal>,
> sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
> I agree that the parallel port is much faster but how fast is fast
My design threshold is 1000hz. That seems to be fast enough to PWM
lights (remember that is 1000 on and 1000 off per second).
> enough? Your relay is going to take ~8ms to turn on. An incandescent
No, that is only for a zero-crossing detecting swith. Typically those I
use for small lighting loads (a few amps) cycle in well under 1ms. I
only use zero-crossing for larger loads (currently up to 40a) where that
characteristic matters, or where I don't need blazing speed.
> It depends on how many relays you are going to control and that's
> pretty limited unless you multiplex your parallel port.
Very. 12 on a standard parallel port, but only 8 of those are 'fast'.
That's why I was asking about multiple parallel boards. :)
The PC is primarily the prototyping platform for sw development. The
final target is a microcontroller that will either be autonomous
(little) or sit on an ethernet (big).
> Do whatever works.
Yup.
sylvan butler
> some info about MIDI. The protocol allows an instrument (or sequencer) to be controlled by "clocks" or "ticks". 48 clocks are sent
I know that. I'm building the instrument that is controlled, not the
controller...
> that a "change" can be a command such as "Begin fade from scene 125 to
And the instrument which actually implements the fade is what I am
building. Unless it uses HUGE variable resistors with HUMONGOUS heat
sinks to dump the waste heat, it will use PWM (Pulse Width Modulation)
to actually fade the light. PWM requires switching the light on and off
very fast, otherwise you will see flicker instead of fade.
That is what I am building. It isn't anything new. It is just
phenomenally cheaper to build, plus I get exactly what I want.
> might also want to Google the archives of CHA using "Christmas lights"
Yup. I've posted a few myself. Such as
http://www.computerchristmas.com/ just a few days ago and almost exactly
two years ago. :)
> or some such. There have been a number of interesting threads on the
> subject every year since I've been posting (and that's a long time)
Yeah, I've been around a while myself. Looks like I just passed my 11th
anniversary in this group. :)
Oh, and BTW, I was doing the stage lighting thing nearly 30 years ago, and
we didn't have any PWM equipment, much less computer control. The light
board in the booth was simply a remote control for large mechanical
dimmers (motor-driven rotary variable resistors) in the 'cage'. A scene
change made all kinds of impressive whirring and buzzing noises, and the
heat coming from that equipment would power a small town. I find PWM
incredible, especially since the introduction of low loss and high-power
MOSFETS. I almost cannot believe the way we set any light level on a
2000w fresnel, with comparatively no heat generation and noise.
Robert L Bass
> very fast, otherwise you will see flicker instead of fade.
Anything faster than about 30 times per second you will see as a fade rather than flickering. However, when using incandescent
bulbs the lamp doesn't actually turn off when power is cut. Instead, the filament starts to cool down. It takes a few ms to "go
out" and by that time the current has turned on again. Triac based theatrical dimmers do what you're trying. These vary in cost
partially with their load capacity.
> That is what I am building. It isn't anything new.
> It is just phenomenally cheaper to build, plus I
> get exactly what I want.
>
>> might also want to Google the archives of CHA using "Christmas lights"
>
> Yup. I've posted a few myself. Such as
> http://www.computerchristmas.com/ just a few days ago and almost exactly
> two years ago. :)
>
>> or some such. There have been a number of interesting threads on the
>> subject every year since I've been posting (and that's a long time)
>
> Yeah, I've been around a while myself. Looks like I just passed my 11th
> anniversary in this group. :)
Heh, heh, heh... You know, Sylvan, if I had taken note of the name in the headers I would have recognized you immediately. :^)
> Oh, and BTW, I was doing the stage lighting thing nearly 30 years ago, and
> we didn't have any PWM equipment, much less computer control. The light
> board in the booth was simply a remote control for large mechanical
> dimmers (motor-driven rotary variable resistors) in the 'cage'.
I've seen those backstage at a few "antique" theater houses over the years but never actually used one. I've worked with 0-10V, a
few proprietary schemes, DMX-512 and MIDI. We used MIDI to integrate lights with sound tracks for a few youth department functions.
I also used it to trigger strobes, foggers and fans at preset times before I installed a computerised control system.
> A scene change made all kinds of impressive whirring
> and buzzing noises, and the heat coming from that
> equipment would power a small town...
Sounds familiar. We decided to upgrade the dimmer closet in a large church in CT a few years ago. I acquired a replacement
transformer -- 440 / 208 WYE. The transformer powered a 400-Amp breaker box which in turn powered the dimmers. Even using triacs,
the air conditioned dimmer room (where the transformer was located) was always about 15 degrees warmer than the rest of the
building. The real fun was installing the thing in the second floor dimming closet though. It took five men to push and pull it up
the stairs.
> I find PWM incredible, especially since the introduction
> of low loss and high-power MOSFETS. I almost cannot
> believe the way we set any light level on a 2000w fresnel,
> with comparatively no heat generation and noise.
Our system had 105 permanent circuits and about 15 open ones that could be attached to rental dimmers if needed. Eight circuits
were 6kW each for running ACLs and such. The rest were 1kW loads though with the gradual changeover to Source IV luminaires, we
were able to get the same light as a 1kW unit with ~600W.
One particular play for which I was the LD had something like 300 cues. I'd plot the lights on my PC at home, configure the
"scenes" on stage, time all the cross-fades and then tweak each one until I was satisfied with everything. At various times we used
a pair of fog machines, a bubbler (ala Lawrence Welk), half a dozen computerized strobes, various moving lights, four manual spots
and, once in a while, all of the FOH fixtures. It was a fun place to go to church.
After doing that for a number of years a few other churches and schools asked me to work on their lighting systems. I learned the
hard way an old saying, "Strand is also a verb." Anyone who hasn worked as an LD will know what that means.
Si Ballenger
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>Very. 12 on a standard parallel port, but only 8 of those are 'fast'.
>That's why I was asking about multiple parallel boards. :)
You may want to look into getting the SIIG parallel port cards
like below. One assumes you have chosen an OS and software that
will support your high speed timing requierments.
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejlbec.c53.Z...@sdba64.internal>:
>On Sat, 21 Oct 2006 02:13:08 -0400, Robert L Bass <rober...@comcast.net>
wrote:
>> sylvan wrote:
>>> I'm talking about the hardware, and you are talking about the protocols
>>> to talk to the hardware.
>>
>> I don't see why you consider MIDI too slow to accomplish the task.
>
>I'm wanting the hardware to control TRIAC or SSR switches, eg a parallel
>binary I/O port. With that I can turn on and off a light (or anything
>else) at a rate over 1000 times per second.
>
>This allows all kinds of creative fades to On, Off, or anywhere in
>between at 100% the whim of my self-written software.
>
>MIDI cannot do that and was never intended to do that. MIDI is a
>control protocol which is used to tell my hardware what to do. I'm not
>interested in another protocol that will tell my hardware what to do. I
>am trying to build hardware. :)
DMX512 (aka DMX-512, DMX512a) can read and(or) write one byte values to each
of 512 addresses ~44 times per second. This is faster than the human flicker
fusion frequency under most circumstances (Q: Do incandescent lights flicker
when run on 50 hz power?)
There are many DIY approaches Google " dmx 512". Also some homebrew and
commercial stuff here: http://www.econtrol.org/dmx512.htm Chips here:
http://www.artisticlicence.com/cat11_1.htm (I have some left-overs I would
part with cheep.)
Search eBay for "USB DMX Interface" and "DMX 512" for a panoply of lighting
devices.
DMX is _designed_ for control of lights. If you've been to a rock concert,
theatre, or play in the last decade, you've seen DMX512 at work. RF and
ethernet implementations have emerged.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejnfq3.u01.Z...@sdba64.internal>:
>I know that. I'm building the instrument that is controlled, not the
>controller...
>
>> that a "change" can be a command such as "Begin fade from scene 125 to
>
>And the instrument which actually implements the fade is what I am
>building. Unless it uses HUGE variable resistors with HUMONGOUS heat
>sinks to dump the waste heat, it will use PWM (Pulse Width Modulation)
>to actually fade the light. PWM requires switching the light on and off
>very fast, otherwise you will see flicker instead of fade.
<snip>
<I find PWM incredible, especially since the introduction of low loss and
<high-power MOSFETS. I almost cannot believe the way we set any light level
<on a 2000w fresnel, with comparatively no heat generation and noise.
Are you referring to reverse-phase AC control using MOSFETs as "PWM"?
Dimming of AC lamps is conventionally done by turning on the current to the
dimmer after the zero-crossing rather than at the zero crossing. This is
conventionally described as "phase control", not " Pulse Width Modification",
whether TRIACs, back-to-back SCRs, IGBTs, or (rarely?) MOSFETs are used as
the semiconductor control elements and whether the switching is conventional
or reverse phase.
Or are you talking about lamps or LED's operated on DC?
Is so, there are DMX512->PWM and 0-10vdc analog-> PWM converters that
modulate DC.
There are of course many DMX512--> AC dimmer and 0-10vdc --> AC dimmers
I've wired parts of my house with 10AWG for ceiling-mounted DC lamps. At
present, I have 24vdc ->> 0 to 12vdc dimmers which are under DMX/0-10vdc
control and have begun investigating high-power LED's (the lamps are still to
pricey for me at this time). LEDs are an arena for PWM in home lighting,
especially when combined with RGB lighting control so that color as well as
intensity can be controlled. High-power LED controller ICs are emerging eg
from Maxim.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
wrote in message <453c2f0d....@news.comporium.net>:
sylvan was asking about cards with four LPTs (the one cited only have two
ports). In any case, LPT ports seem to be an inefficient way to get 4 x 8 =
32 'fast' TTL outputs.
In bygone days, the LPTs were convenient because they were supported by the
OS. As Si implies above, attempting to control multiple LTP's in real time
deterministically at 1000hz with a PC without a real- time operating system
would cause one to see many more flashes and other glitches owing to OS and
software timing problems in the PC than anything caused by the hardware.
I presume that sylvan gets his "1000hz" requirement from 120 zero-crossings
per second * 8 positions per zero crossing = OFF + 8 other intensity values.
Pretty crude. Not sure why he would go this route. Conventional dimmers do
much better than that -- eg DMX512 nominally has 255 intensity values, some
X-10 implementations nominally 32 different values, etc.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejlbec.c53.Z...@sdba64.internal>:
>On Sat, 21 Oct 2006 02:13:08 -0400, Robert L Bass <rober...@comcast.net>
wrote:
>> sylvan wrote:
>>> I'm talking about the hardware, and you are talking about the protocols
>>> to talk to the hardware.
>>
>> I don't see why you consider MIDI too slow to accomplish the task.
>
>I'm wanting the hardware to control TRIAC or SSR switches, eg a parallel
>binary I/O port. With that I can turn on and off a light (or anything
>else) at a rate over 1000 times per second.
>
>This allows all kinds of creative fades to On, Off, or anywhere in
>between at 100% the whim of my self-written software.
1000 on-offs per second controlling 60 hz AC lighting yields:
(1000/sec) /(120 zero-crossing/sec) = 8.33 control choices per second.
As a practical matter, about one-third of those possible on-off signals will
fall so early in the AC cycle that they wouldn't produce enough current to
make visible light (although they would use up electricity).
So as a practical matter, unless you first convert the AC to DC, you might
have as few as 5 distinct illumination levels.
This is probably completely adequate for most scene-control purposes where
slow, smooth transitions from scene to scene are unimportant, but you are
touting this "1000hz" approach as being as providing "all kinds of creative
fades" and "anywhere in between" when as a practical matter, your "1000hz"
approach is much cruder than even the simplest X-10 dimmer.
And it pales in comparison to DMX-512 with 255 distinct values and the dimmer
curves and pre-heat values (i.e, non-linear relationship between input
control value and phase value) are part and parcel of even moderately
sophisticated implementations.
Are you doing more work and accomplishing less with this technique? Or do I
misunderstand something quite completely -- wouldn't be the first or last
time ;-)
... Marc
Marc_F_Hult
www.ECONtrol.org
Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote in message
<8hqpj29mh1i2k7027...@4ax.com>:
255 levels * 44 changes * 120 zero-crossings/sec = 1,346,400 hz
= 1.35 mhz = frequency needed to bit-bang a phase-controlled AC dimmer with
the same number of intensity levels and time resolution as DMX512.
(Assuming phase control. The arithmetic for amplitude control is a bit
different and bumps into other limitations such as flicker.)
sylvan is asking about doing this from a PC bus with off-the-shelf LPT cards
so, presumably requires a real-time OS that runs on conventional x86 PC
hardware such as Windows CE, Labview RT, QNX, BeOS, VxWorks,
RTLinux/FreeRTOS/Linux2.6.18+ and so on.
(I wonder what use the 100 MB release of Windows PE 2.0 might have for HA if
the 24-hr run limitation could be overcome/thwarted? Not RT, but small
enough for simple installation and use without a hard drive.
http://www.microsoft.com/technet/windowsvista/deploy/winpe.mspx )
... Marc
Marc_F_Hult
www.ECOntrol.org
sylvan butler
> In bygone days, the LPTs were convenient because they were supported by the
> OS
Or mostly as standard hardware that was easy to access both on the SW
and hardware side. (though a simple design change by IBM in the
original to swap the addresses of the status and control ports would
have made high speed much easier!) A SW example: port write to 0x378
switches 8 lines simultaneously. 0x37a does four lines. On anything
faster than a 4.77mhz 8088, the cycle time is limited by wait states on
the ISA bus. (PCI (and microchannel) reduce or eliminate most of the
CPU wait states.) This means that the slowest PC you can buy today can
set the state of 8 lines hundreds of thousands of times per second.
Compare that with an 8255 solution which takes multiple port writes to
set the state of any set of the 24 output lines. If it takes two
writes, you just cut your maximum rate in half. Three writes == 1/3.
Etc. Even the parallel port multiplexing solutions which take five or
six writes are way faster than my 1000hz target (which only requires
2000 writes per second on a standard parallel port).
> As Si implies above, attempting to control multiple LTP's in real time
> deterministically at 1000hz with a PC without a real- time operating system
The 1000hz is the design target. And modern PCs are fast enough that an
ancient 386/20 laptop running linux has worked great for simple testing.
It has worked so well, I may even change my stuff to be a kernel driver.
The ancient PC speaker driver would produce full sound effects using
1bit PWM under linux. As long as you kept the sounds from about 1000hz
to 12,000hz and didn't mind a bit of jumpiness on the keyboard. :)
Given that, I expect I could run fades on 8 lights (one parallel port)
from this 386/20 without needing any "real time" anything.
In reality, not all bits on all ports will need to be toggling that
fast. Mostof the time, no bits will be toggling. When a light is
full-on or full-off the system is idle. It is only while fading or
maintaining a dim level that any toggling will need to happen.
> would cause one to see many more flashes and other glitches owing to OS and
> software timing problems in the PC than anything caused by the hardware.
Again, the PC is mostly a SW development and prototyping platform.
There is no OS involved. It boots DOS and loads my code which takes
over the entire system. Or another way of saying it, I've written the
OS. Even the really little, cheap pics can do 4 channels (bits aka
loads). That's what's in many of the remotable dimmers.
> I presume that sylvan gets his "1000hz" requirement from 120 zero-crossings
> per second * 8 positions per zero crossing = OFF + 8 other intensity values.
Not even close.
> Pretty crude. Not sure why he would go this route.
I'm not.
> Conventional dimmers do
> much better than that -- eg DMX512 nominally has 255 intensity values, some
Think of it as me building a DMX512 or X10 dimmer. How does it actually
create the varying intensities? By turning on and off the light many
times per second. That's what I'm doing.
sylvan butler
> Or are you talking about lamps or LED's operated on DC?
> Is so, there are DMX512->PWM and 0-10vdc analog-> PWM converters that
> modulate DC.
I'm modulating D.C., or rather, creating modulated D.C. The technique
of modulating the D.C. is PWM. That D.C. is then used to switch a
triac to control A.C. loads. Phase syncronization is mainly needed to
control R.F. and sometimes to control switching transients. With fairly
low power loads (typically under 200 watts) R.F. is minimal and
controllable in other ways. Switching transients aren't significant
with primarily resistive or incandescent loads.
> There are of course many DMX512--> AC dimmer and 0-10vdc --> AC dimmers
You seem to be confusing how the dimmer is controlled (with DMX or
0-10vdc or...) with how the dimmer controls the A.C. I'm doing the
latter. Not real interested in the former at the present time.
> control and have begun investigating high-power LED's (the lamps are still to
> pricey for me at this time). LEDs are an arena for PWM in home lighting,
> especially when combined with RGB lighting control so that color as well as
> intensity can be controlled. High-power LED controller ICs are emerging eg
> from Maxim.
Yes, very cool stuff. It is just beginning to hit the market, and looks
to have potential to revolutionize ambient lighting.
sylvan butler
> DMX512 (aka DMX-512, DMX512a) can read and(or) write one byte values to each
> of 512 addresses ~44 times per second. This is faster than the human flicker
If DMX could issue 44 commands per second per address, it could turn a
light on and then off only 22 times per second. Is that what you meant?
> fusion frequency under most circumstances (Q: Do incandescent lights flicker
> when run on 50 hz power?)
A: No, because incandescent lights are very, very slow.
Q: Do fast acting lights (LEDs, fast phospher in fluorescent tubes,
CRTs, LEDs, etc) flicker when run on 50hz power?
A: Yes. Even if not consciously apparent to the human eye, 50hz and
60hz and even 120hz flicker is easily detectable with primitive
mechanical instruments, and is known to cause eye strain during extended
exposure.
> DMX is _designed_ for control of lights.
Yup, and someday I may want to add a DMX interface to my devices so they
can be controlled from such a standard protocol. It's not on the
vintage chart today.
sylvan butler
> touting this "1000hz" approach as being as providing "all kinds of creative
> fades" and "anywhere in between" when as a practical matter, your "1000hz"
> approach is much cruder than even the simplest X-10 dimmer.
I don't know how come I cannot seem to communicate this...
Perhaps today's batch of posts will connect.
How do you think the X-10 dimmer actually fades the light?
> And it pales in comparison to DMX-512 with 255 distinct values and the dimmer
And the DMX dimmers actually control the light how?
> Or do I
> misunderstand something quite completely -- wouldn't be the first or last
> time ;-)
I think so!
You are looking at the problem from the "top" -- how to control a
dimmer.
I'm looking at the problem from the bottom -- how to build a dimmer.
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejqm7f.a3i.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 11:25:18 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> Or are you talking about lamps or LED's operated on DC?
>> Is so, there are DMX512->PWM and 0-10vdc analog-> PWM converters that
>> modulate DC.
>
>I'm modulating D.C., or rather, creating modulated D.C. The technique
>of modulating the D.C. is PWM. That D.C. is then used to switch a
>triac to control A.C. loads. Phase synchronization is mainly needed to
>control R.F. and sometimes to control switching transients. With fairly
>low power loads (typically under 200 watts) R.F. is minimal and
>controllable in other ways. Switching transients aren't significant
>with primarily resistive or incandescent loads.
ROTFL
A TRIAC dimming household 60 hz AC can be switched on *exactly* twice every
1/60th of a second: once during 0-180 degrees and once during 180-360
degrees. And a TRIAC can _never_ be 'switched off'. So what you say you are
doing (as I understand it) simply won't work. Everything that can be done to
control a TRIAC can be done with no more than 120 low-to-high transitions per
second. Having the ability to switch at 1000 hz is intrinsically no more
useful than 120. It is _when_ during the cycle with respect to the
zero-crossing that the SCR is turned ON that determines the dim level.
>> There are of course many DMX512--> AC dimmer and 0-10vdc --> AC dimmers
>
>You seem to be confusing how the dimmer is controlled (with DMX or
>0-10vdc or...) with how the dimmer controls the A.C. I'm doing the
>latter. Not real interested in the former at the present time.
No, it's all quite clear to me. DMX can change the 0-255 dim level setting up
to 44 times per second. Based on the 0-255 level instruction it receives via
DMX (which can change up to 44 times per second) the dimmer module (in the
case of household AC lighting) sets the dim level of the TRIAC/SCRs by either
turning the TRIAC into conduction at 0 and 180 degrees (= Full ON), at some
phase angle 0 < a < 180 and 180< a < 360 (= dimmed"), or not at all (= full
OFF). This can be done (eg) with a comparator that compares the voltage of a
simple (eg) 0-10 volt ramp (sawtooth signal) that begins at the zero crossing
and a 0-10vdc DC control signal. When the ramp reaches the value of the
control signal, the comparator goes high and causes the TRIAC to go into
conduction. This is repeated 120 times a second.
So being able to switch at 1000hz or 10000hz or a gigahertz has no intrinsic
advantage over switching at 120hz (at the right times) in controlling
TRIACs/SCRs. But only being able to turn the TRIAS on at 1000hz/120hz = 8.33
(dimensionless) different phase angles (your 1000hz case) means that you
will only have a maximum of 1000/120 = 8.33 different dimmer settings
(assuming that you are synchronized with zero crossing, which you don't seem
to be). In contrast DMX512 has 255 different dim levels (my previous comments
about dimmer curves, preheat and un-useful phase angles not withstanding).
This is the same as I wrote before. What you need to grok is that a TRIAC is
not turned OFF when the TRIAC gate control signal goes low (= OFF). So
turning the control signal ON-OFF does NOT turn the TRIAC ON-OFF lock-step.
... Marc
Marc_F_Hult
www.EControl.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejqljo.a3i.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 11:49:44 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>
>> I presume that sylvan gets his "1000hz" requirement from 120
>>zero-crossings per second * 8 positions per zero crossing = OFF + 8 other
>>intensity values.
>
>Not even close.
Then please do post how you chose 1000 hz.
>> Pretty crude. Not sure why he would go this route.
>
>I'm not.
>
>> Conventional dimmers do much better than that -- eg DMX512 nominally has
>> 255 intensity values, some
>
>Think of it as me building a DMX512 or X10 dimmer. How does it actually
>create the varying intensities? By turning on and off the light many
>times per second. That's what I'm doing.
No. DMX512 does not "turn[] on and off the light off many times per second".
DMX512 can set a new, 0-255 dimmer level up to 44 times a second, but it is
the dimmer that turns the conduction of a TRIAC or back-to-back SCR ON
depending on the phase at each half cycle. A TRIAC cannot be "turned off"
during 0< a < 180 and 180 < a <360 degrees. It turns _itself_ OFF at 0 and
270 degrees whether we like it or not.
If you are turning ON the light many times per second, how do you synchronize
with line frequency? If you don't, what happens if you turn on the light when
it happens to be at 0 or 180 degrees compared to when it happens to be at 90
or 270 degrees?
... Marc
Marc_F_Hult
www.ECONtrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejqm7f.a3i.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 11:25:18 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> Or are you talking about lamps or LED's operated on DC?
>> Is so, there are DMX512->PWM and 0-10vdc analog-> PWM converters that
>> modulate DC.
>
>I'm modulating D.C.,
So you first rectify the AC ?
>or rather, creating modulated D.C.
>The technique
>of modulating the D.C. is PWM. That D.C. is then used to switch a
>triac to control A.C. loads.
OK. But what you end up with is a poorly-timed control signal for the TRIAC
gate. What's the point? You end up with more noise and less resolution (of
different dim levels) than if you were synchronized. I guess I answered my
own question: you don't have to synchronize with the zero crossing ;-)
>Phase syncronization is mainly needed to
>control R.F. and sometimes to control switching transients. With fairly
>low power loads (typically under 200 watts) R.F. is minimal and
>controllable in other ways. Switching transients aren't significant
>with primarily resistive or incandescent loads.
See my other comments.
>
>> There are of course many DMX512--> AC dimmer and 0-10vdc --> AC dimmers
>
>You seem to be confusing how the dimmer is controlled (with DMX or
>0-10vdc or...) with how the dimmer controls the A.C. I'm doing the
>latter. Not real interested in the former at the present time.
No I am not ;-) What you describe is a very low-resolution way ( max 8 dim
levels at 1000 hz) to dim AC power using TRIACS or back-to-back SCRs.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnejqmkj.a3i.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 09:01:36 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> DMX512 (aka DMX-512, DMX512a) can read and(or) write one byte values to
each
>> of 512 addresses ~44 times per second. This is faster than the human
flicker
>
>If DMX could issue 44 commands per second per address, it could turn a
>light on and then off only 22 times per second. Is that what you meant?
No it is not. I mean what I wrote. It can change the steady-state 0-255 dim
level 44 times per second. The dimmer does the dimming.
>
>> fusion frequency under most circumstances (Q: Do incandescent lights
>>flicker when run on 50 hz power?)
>
>A: No, because incandescent lights are very, very slow.
But they are what you are controlling, no?
>
>Q: Do fast acting lights (LEDs, fast phospher in fluorescent tubes,
>CRTs, LEDs, etc) flicker when run on 50hz power?
They do not turn on-off faster than the human flicker fusion frequency which
is what I wrote. And you can't change the 60 hz frequency of the light
intensity modulation by turning the TRIAC gate control signal ON-OFF at
1000hz or one gigahertz or any other frequency for reasons I have posted
tediously already ;-)
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote in message
<m82rj2966h57g91kt...@4ax.com>:
To expand and clarify: In order to provide the gate control signal for a
TRIAC/ Back-to-Back SCR dimmer with the 256 dim levels achieved by DMX512,
your fixed-frequency scheme needs to operate at a frequency of 120*256 =
30720 hz.
So your 1000hz target, which you suggest/imply is itself extravagant, is a
factor of 30 slower than what is needed to accomplish what off-the-shelf,
(relatively ;-)inexpensive, globally accepted, ANSI-standard,
http://www.usitt.org/standards/DMX512_FAQ.html DMX-512 lighting can do.
You can change the arithmetic co9mpletely by timing the gate control voltage
with the AC line zero crossing, but if you do that with a PC, all you've
really done is create the world's largest (? I dunno ;-) dimmer controller at
a substantial cost in time expended, size, power consumption, complexity, and
difficulty of repair and maintenance by others.
'Course I do things related to HA just as time-consuming and idiosyncratic,
so no criticism is implied ;-)
... Marc
Marc_F_Hult
www.ECOntrol.org
John Haskey
sylvan butler <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote:
>
>MIDI is inherently slow.
>
>MIDI runs at several bytes per second. Each command is a few dozen
>bytes. Do the math. It's slow.
>
The discussion has moved on but these statements need to be corrected.
With MIDI, a command to 'turn something on' with up to 128 'intensities'
is 3 bytes worst case and 2 bytes best case. No where near the 'few
dozen bytes' stated by the previous poster.
MIDI runs at 31.25Khz. A byte can be sent in 320 microseconds. That's
about 3 bytes per millisecond or 3000 bytes per second. That's a few
more than the previous poster's 'several bytes per second' I think.
Robert L Bass
Most use triacs.
> I'm looking at the problem from the bottom -- how to build a dimmer.
Not any more. You explained that already and I understand you. I'm fairly certain Marc does, too. His point is that your design
criteria may not yield what you want.
FWIW, Marc has built a DMX-512 compatible lighting controller for home use. I had references to his work on my FAQ... until
hurricane Charley came along. Oh, well.
I'm quite interested in your design. I hope you can make it work to your satisfaction. These kinds of projects tend to inspire
people to produce commercially viable products and that is good not only for the DIY folks here but also for retailers like me who
cater to them. :^)
Whatever protocol you choose one you're at that point, I hope you'll share about it here as the job progresses.
sylvan butler
>> And the DMX dimmers actually control the light how?
>
> Most use triacs.
Yup. And the triac is controlled by a microprocessor switching the gate
current on and off at least 120 times per second.
Of course, you (Robert) are responding to a message intended for
Marc. :)
> I understand you. I'm fairly certain Marc does, too.
I am confident he does not.
> FWIW, Marc has built a DMX-512 compatible lighting controller for home use.
I wonder if he created the software that actually runs in the
microcontrollers inside each dimmer / load controller...
sylvan butler
><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
><slrnejqljo.a3i.Z...@sdba64.internal>:
> Then please do post how you chose 1000 hz.
With 1000hz I can smoothly synthesize any waveform from D.C. up to 500hz
and of course squarewave up to 1000hz. Then the interface electronics
will allow me to use D.C. lights (with a class-D amplifier) or A.C.
lights (with a triac or SSR).
>>Think of it as me building a DMX512 or X10 dimmer. How does it actually
>>create the varying intensities? By turning on and off the light many
>>times per second. That's what I'm doing.
> No. DMX512 does not "turn[] on and off the light off many times per second".
DMX doesn't, but the DMX dimmer does. That is EXACTLY how EVERY SOLID
STATE DIMMER works. Even a DMX dimmer and same with an X10 dimmer.
Read http://home.howstuffworks.com/dimmer-switch2.htm if you don't want
to believe me. (microprocessor controlled dimmers simply replace the
analog R.C. timing circuit with a digital output pin)
> If you are turning ON the light many times per second, how do you synchronize
> with line frequency?
I don't.
> If you don't, what happens if you turn on the light when
> it happens to be at 0 or 180 degrees compared to when it happens to be at 90
> or 270 degrees?
When gate (trigger) current is available for the triac, it will conduct
the A.C. waveform. When gate current is not available, it will not
conduct beyond the zero crossing. Basic electronics.
sylvan butler
> A TRIAC dimming household 60 hz AC can be switched on *exactly* twice every
> 1/60th of a second: once during 0-180 degrees and once during 180-360
> degrees. And a TRIAC can _never_ be 'switched off'. So what you say you are
The microprocessor will switch on and off the gate current. The triac
will cease conducting within 1/120 of a second (at 60hz). That's rather
faster than your hand can interrupt the A.C. using a mechanical switch.
It is also reasonable compared to typical mechanical power relays. If
you don't want to call that "switched off" that is your prerogative nit.
> doing (as I understand it) simply won't work.
But I can see it does.
> OFF). This can be done (eg) with a comparator that compares the voltage of a
> simple (eg) 0-10 volt ramp (sawtooth signal) that begins at the zero crossing
> and a 0-10vdc DC control signal. When the ramp reaches the value of the
> control signal, the comparator goes high and causes the TRIAC to go into
> conduction. This is repeated 120 times a second.
Yup. Now how would your DMX dimmer generate the 0-10vdc control signal
for the comparator? Nyquist might help you understand how, and also
how/why I can simplify the whole mess with a bit of software and make a
generic controller, just as long as I keep my switching frequency many
times faster than line frequency. (And 1khz just so happens to be a
typical lower bound in many PWM designs.)
G. Morgan
<rober...@comcast.net> wrote:
>I had references to his work on my FAQ... until
>hurricane Charley came along. Oh, well.
I was wondering why you took down your famed "FAQ". I have a copy of
it sucked with Teleport Pro in HTML and the .zip file in RoboHelp
format taken from your /images directory you left unprotected.
No, you can't have it.
--
-Graham
(remove the double e's to email)
sylvan butler
> No I am not ;-) What you describe is a very low-resolution way ( max 8 dim
> levels at 1000 hz) to dim AC power using TRIACS or back-to-back SCRs.
Your prediction of 8 dim levels is without basis or merit.
Assuming 60hz. Typical phase control the triac must be triggered 120
times per second at a TBD offset after the zero crossing. If the triac
is instead triggered exactly twice as often, it will function exactly
the same -- the output A.C. waveform will be identical. Same if the
triac is triggered exactly 4x as often. Or 8x as often. 8x is 960/sec.
If I instead trigger at 1000/sec, that is a max of 4% error when it
happens at random instead of synchronized to zero crossings. This error
has imperceptible effect (to my eye when using incandescent lighting).
sylvan butler
> No it is not. I mean what I wrote. It can change the steady-state 0-255 dim
> level 44 times per second. The dimmer does the dimming.
And I am building dimmers, thus I need to turn the light on and off many
times per second and DMX is irrelevent (unless you can offer DMX dimmers
in the $5 to $10 per channel range when buying 4 channel blocks).
>>A: No, because incandescent lights are very, very slow.
>
> But they are what you are controlling, no?
For the most part. And their slow speed is why a 60hz A.C. dimmer
works. But just because the output cannot reproduce the frequency, that
is no reason not to have the frequency. E.g. CD audio was (and remains)
a useless waste a fidelity for most purchasers of CD content.
sylvan butler
><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
><slrnejqmkj.a3i.Z...@sdba64.internal>:
>>> (Q: Do incandescent lights flicker when run on 50 hz power?)
>A: No, because incandescent lights are very, very slow.
>>Q: Do fast acting lights (LEDs, fast phospher in fluorescent tubes,
>>CRTs, LEDs, etc) flicker when run on 50hz power?
> They do not turn on-off faster than the human flicker fusion frequency which
> is what I wrote.
But they do. I and many others see the flicker from LEDs run on
unfiltered 60hz A.C. simply by turning ones head causing eyes to sweep
past the LEDs. Many people complain of this with LED christmas lights
and night lights.
Fluorescent lighting phosphers are a bit slower, and the 120/sec
flashing is much faster, but they also produce easily discernable
flicker that bothers many people and is proven to exhaust eyes even for
those people who are not consciously aware of flicker.
Robert L Bass
>>> How does it actually create the varying intensities?
>>> By turning on and off the light many times per
>>> second. That's what I'm doing.
>>
>> No. DMX512 does not "turn[] on and off the light off many times per second".
>
> DMX doesn't, but the DMX dimmer does. That is EXACTLY how EVERY SOLID
> STATE DIMMER works. Even a DMX dimmer and same with an X10 dimmer.
The DMX dimmer switches the current on 120 x per second. The only thing that changes is how long it waits after zero crossing to
switch it on. It can't switch the current off again in mid-phase. It can't turn the load on and off more times because it has to
wait for zero crossover for the current to turn off.
--
Regards,
Robert L Bass
=============================>
Bass Home Electronics
941-866-1100
Robert L Bass
>>
>> Most use triacs.
>
> Yup. And the triac is controlled by a microprocessor
> switching the gate current on and off at least 120 times
> per second.
>
> Of course, you (Robert) are responding to a message intended for
> Marc. :)
It's a forum. :^)
>> I understand you. I'm fairly certain Marc does, too.
>
> I am confident he does not.
Perhaps not but he and I both know how triac dimmers work and I know you can't switch them on and off more than 120 x per second.
>> FWIW, Marc has built a DMX-512 compatible
>> lighting controller for home use.
>
> I wonder if he created the software that actually runs in the
> microcontrollers inside each dimmer / load controller...
It's not about the software. There are limitations of the hardware itself. If you want to use a triac you're not going to switch
it on/off more than 120 times a second, regardless what software you use.
--
Regards,
Robert L Bass
=============================>
Bass Home Electronics
941-866-1100
Si Ballenger
<alar...@geemail.com> wrote:
>On Wed, 25 Oct 2006 02:37:15 -0400, "Robert L Bass"
><rober...@comcast.net> wrote:
>
>>I had references to his work on my FAQ... until
>>hurricane Charley came along. Oh, well.
>
>
>I was wondering why you took down your famed "FAQ". I have a copy of
>it sucked with Teleport Pro in HTML and the .zip file in RoboHelp
>format taken from your /images directory you left unprotected.
>
>No, you can't have it.
Reveiling your secret stash? ;)
Frank Olson
He reads it every few months or so. It's a great "how-not-to" resource.
Dan Lanciani
| On Mon, 23 Oct 2006 23:42:22 -0400, Marc_F_Hult <MFH...@nothydrologistnot.com> wrote:
| > No I am not ;-) What you describe is a very low-resolution way ( max 8 dim
| > levels at 1000 hz) to dim AC power using TRIACS or back-to-back SCRs.
|
| Your prediction of 8 dim levels is without basis or merit.
|
| Assuming 60hz. Typical phase control the triac must be triggered 120
| times per second at a TBD offset after the zero crossing. If the triac
| is instead triggered exactly twice as often, it will function exactly
| the same -- the output A.C. waveform will be identical. Same if the
| triac is triggered exactly 4x as often. Or 8x as often. 8x is 960/sec.
| If I instead trigger at 1000/sec, that is a max of 4% error when it
| happens at random instead of synchronized to zero crossings. This error
| has imperceptible effect (to my eye when using incandescent lighting).
What (not synchronized to the zero crossing) triac trigger waveform
will you synthesize to obtain an approximately 50% dim level?
Dan Lanciani
ddl@danlan.*com
Marc_F_Hult
<133...@news1.IPSWITCHS.CMM>:
Now ya dunnit, Dan ;-) This may be the last we hear from sylvan on the issue.
As you know, the independent variable controlling output in a TRIAC-based
dimmer is phase or time offset with respect to the zero crossing. But sylvan
does not (knowingly) synchronize the trigger with the AC waveform. So sylvan
has no adequate answer to your question.
There are at least three possible explanations for his claim that he can
control TRIAC dimming with a 1000hz signal not synchronized to the zero
crossing but none that I can divine that support the claim of actually
deterministically providing many different dim levels without flicker.
1) His actual trigger (control) signal has a significant component of 60hz AC
noise ("hum") and so is in fact inadvertently synchronized to the AC line
2) His dimmer circuit skips entire half-cycles. This would happen if his
trigger repeated at less than 120 hz. One could, for example, make an
approximately 50% dimmed by repeated cycles of a 8.2 millisecond burst of
1khz square wave followed by a low signal 8.4 millisecond in duration, thus
only triggering on (approximately) alternate 1/2 cycles. This is why I pressed
him on the flicker issue. (We have been assured that his TRIAC-based dimmer
system meets rigorous theoretical and empirical tests for flicker.)
3) The dimmer is in his head and hasn't been instantiated.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnek5vme.vse.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 23:42:22 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> No I am not ;-) What you describe is a very low-resolution way ( max 8 dim
>> levels at 1000 hz) to dim AC power using TRIACS or back-to-back SCRs.
>
>Your prediction of 8 dim levels is without basis or merit.
We disagree, and you also disagree with the physics of the matter IMO.
>Assuming 60hz. Typical phase control the triac must be triggered 120
>times per second at a TBD offset after the zero crossing.
Right. And because you are not synchronized with the power line, you are not
synchronized with the zero crossing and so the TBD (To Be Determined) offset
from the zero crossing is not known and *cannot* Be Determined. be
Whatever periodic waveform you use, the dimming value on the first cycle
depends on _when_ you start that periodic waveform, right?
And since you are not synchronized, by definition, the dimming level on the
first cycle is unknown. Right? And is unknown on the second half cycle, etc.
In other words, your 'approach' does not use the between dim level and delay
in sec, degrees or radians.
>If the triac
>is instead triggered exactly twice as often, it will function exactly
>the same -- the output A.C. waveform will be identical. Same if the
>triac is triggered exactly 4x as often. Or 8x as often. 8x is 960/sec.
Sure. As I wrote previously, what happens to the control voltage _after_ the
threshold is reached in any given half cycle has no effect on operation.
The dim level is determined completely by the "To Be Determined" offset as
you've stipulated. But your system has no way of determining the offset, so it
has no (intended ) way of dimming in a deterministic way except by skipping
entire half-cycles.
>If I instead trigger at 1000/sec, that is a max of 4% error when it
>happens at random instead of synchronized to zero crossings.
??? Where does 4% come from?
0.4% (not 4%) relates to how close 960 is to 1000 but that's not relevant to
calculation of the dimming error.
You've already agreed that dimming is determined by the offset after zero
crossing (units = seconds, radians, or degrees), so the calculation of the
dimming error by definition looks like:
Percent Error = (TO-AO)/TO *100%
where TO = Theoretical Actual Offset after zero crossing ,
in seconds, radians, or degrees
AO = Actual Offset after zero crossing, in seconds,
radians, or degrees
What values do/would you use in this calculation ?
>This error has imperceptible effect (to my eye when using incandescent
>lighting).
What does your TRIAC-based dimmer output look like on a scope?
A dimmer curve for TRIAC dimmers shows the relationship between dim level and
offset (in seconds, radians or degrees).
See my spreadsheet at
http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
Please describe the relationship you use between your 'waveform' and the
resulting _constant_ , non-flickering dim level.
... Marc
Marc_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnek608s.vse.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 23:48:07 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> On Mon, 23 Oct 2006 18:13:07 -0600, sylvan butler
>><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
>><slrnejqmkj.a3i.Z...@sdba64.internal>:
>
>>>> (Q: Do incandescent lights flicker when run on 50 hz power?)
>
>>A: No, because incandescent lights are very, very slow.
>
>>>Q: Do fast acting lights (LEDs, fast phospher in fluorescent tubes,
>>>CRTs, LEDs, etc) flicker when run on 50hz power?
>
>> They do not turn on-off faster than the human flicker fusion frequency >>
which is what I wrote.
>
>But they do. I and many others see the flicker from LEDs run on
>unfiltered 60hz A.C. simply by turning ones head causing eyes to sweep
>past the LEDs. Many people complain of this with LED christmas lights
>and night lights.
This is not how nor the conditions under which the human flicker fusion
frequency is conventionally determined. The fff not a measure of fatigue.
Please read what I wrote.
>Fluorescent lighting phosphers are a bit slower, and the 120/sec
>flashing is much faster, but they also produce easily discernable
>flicker that bothers many people and is proven to exhaust eyes even for
>those people who are not consciously aware of flicker.
But 'exhausted eyes" are not a measure of the human flicker fusion frequency.
You are confounding a formally defined measure (at least it was when I took
psychology 35 years ago) with other vision-related phenomena.
But all this is silly. The point here was to assure than if we discovered that
your dimmer kinda sorta works by skipping 1/2-cycles, you wouldn't claim that
to be acceptable performance.
... Marc
Marc_F_Hult
www.ECControl.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnek60kk.vse.Z...@sdba64.internal>:
>On Mon, 23 Oct 2006 23:48:07 -0400, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> No it is not. I mean what I wrote. It can change the steady-state 0-255 dim
>> level 44 times per second. The dimmer does the dimming.
>
>And I am building dimmers, thus I need to turn the light on and off many
>times per second and DMX is irrelevent (unless you can offer DMX dimmers
>in the $5 to $10 per channel range when buying 4 channel blocks).
>
>>>A: No, because incandescent lights are very, very slow.
>>
>> But they are what you are controlling, no?
>
>For the most part. And their slow speed is why a 60hz A.C. dimmer
>works.
No it is not. Are you claiming that motion pictures 'don't work'.
>But just because the output cannot reproduce the frequency, that
>is no reason not to have the frequency. E.g. CD audio was (and remains)
>a useless waste a fidelity for most purchasers of CD content.
ROTFL
What does "output can't reproduce the frequency" mean?
"What does it mean to "have the frequency"? Is that like grooving with it, or
having good vibes?
... Marc
Marc_F_Hult
www.EControl.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnek5spo.vse.Z...@sdba64.internal>:
>On Wed, 25 Oct 2006 02:37:15 -0400, Robert L Bass <rober...@comcast.net>
wrote:
>>> And the DMX dimmers actually control the light how?
>>
>> Most use triacs.
>
>Yup. And the triac is controlled by a microprocessor switching the gate
>current on and off at least 120 times per second.
>
>Of course, you (Robert) are responding to a message intended for
>Marc. :)
>
>> I understand you. I'm fairly certain Marc does, too.
>
>I am confident he does not.
>
>> FWIW, Marc has built a DMX-512 compatible lighting controller for home use.
>
>I wonder if he created the software that actually runs in the
>microcontrollers inside each dimmer / load controller...
>
>sdb
At first I thought sylvan might just not be explaining himself well, but it
now seems more likely that he doesn't understand the fundamentals.
For folks interested in _actually_ creating dimmers using microcontrollers or
analog techniques, I created a link to a spreadsheet on my web site that I
prepared about five years ago:
http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
This spreadsheet solves the equations that provide the numerical values to
program the delay-after-zero-crossing for a TRIAC-based dimmer either by
bit-banging with a microcontroller or other processor including a PC or with
an analog comparator.
It provides tables and graphs of:
0-10vdc control signal, Vdc
DMX512 0-255 value, also sequence number for dimmer steps in dimmer curves
Fraction of AC cycle
Phase angle, degrees
Phase angle, radians
Delay after zero-crossing, milliseconds
Output voltage, Vrms
Relative luminous intensity for a typical tungsten lamp, %
Email me if you want the .xls version (a .pdf is posted).
'Course neither the equations nor the data has much meaning for sylvan who
claims to create high-resolution, flicker-free control of TRIAC dimmers
_without_ synchronization to the powerline with a 1000hz fixed-frequency
trigger!
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
One purpose for my recent posts on this topic has simply been to provide an
antidote to the mis-information posted so that others don't waste their time.
But controlling 110/220 volt AC also needs to be done SAFELY and in compliance
with applicable building codes. Folks that might be mislead into homebrewing
sylvan's (apparently) hypothetical nonsense might also create potentially
unsafe hardware which could be disastrous -- especially with holiday lighting
which is typically installed outdoors and in a temporary fashion.
So ... *Please* be careful and know your limitations.
That said, folks that are interested in _actually_ dimming TRIACS,
back-to-back SCRs or SSRs based on them may be interested in a spreadsheet
that I created about 5 years ago.
http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
This spreadsheet solves the equations that provide the numerical values to
program the delay-after-zero-crossing for a TRIAC-based dimmer either by
bit-banging with a microcontroller or other processor including a PC or using
analog techniques.
It provides tables and graphs of:
0-10vdc control signal, Vdc
DMX512 0-255 value, also sequence number for dimmer steps in dimmer curves
Fraction of AC cycle
Phase angle, degrees
Phase angle, radians
Delay after zero-crossing, milliseconds
Output voltage, Vrms
Relative luminous intensity for a typical tungsten lamp, %
Email me if you want the .xls version (a .pdf is posted).
... Marc
Marc_F_Hult
www.ECOntrol.org
On Sat, 28 Oct 2006 00:05:44 -0600, sylvan butler
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnek5spo.vse.Z...@sdba64.internal>:
>On Wed, 25 Oct 2006 02:37:15 -0400, Robert L Bass <rober...@comcast.net>
sylvan butler
><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
><slrnek5vme.vse.Z...@sdba64.internal>:
>>If I instead trigger at 1000/sec, that is a max of 4% error when it
>>happens at random instead of synchronized to zero crossings.
>
> ??? Where does 4% come from?
(1000-960)/1000 gives 4% error in frequency. Or I thought it did...
> 0.4% (not 4%) relates to how close 960 is to 1000
It does? Hmm.
Oh, I should clarify that right now I'm not frequency limiting to 1khz.
1khz is my lower bound on the design, not to be confused with "will
operate at 1khz" and definitely not an "up to 1khz" target. The only
limits I have on output waveform right now are duty cycle of the output
and how often the processor can repeat the synth loop.
sylvan butler
Depends on dim level. For 100% bright the output voltage waveform is
essentially complete (a bit of noise near 0-crossing). For 0% bright
there is no output voltage. At 50% duty cycle the light appears
significantly dimmed and the voltage applied to the light shows
apparently random parts of the complete sine form with a rare complete
half-cycle.
> A dimmer curve for TRIAC dimmers shows the relationship between dim level and
> offset (in seconds, radians or degrees).
For typical triac dimmers the output waveform shows a relationship
between voltage (or current) and time. This does not have any linear or
easily calculable relationship to dim level.
> Please describe the relationship you use between your 'waveform' and the
> resulting _constant_ , non-flickering dim level.
I have not yet attempted any perceptual coding.
sylvan butler
I don't know up front, that is a software calibration issue related to
the lamp being controlled and visual perception.
If you meant 50% power level rather than 50% light level, then I would
synth a 50% on-time, and know that with a 4% error limit I would be
close enough. But again, that is power, not light.
sylvan butler
> There are at least three possible explanations for his claim that he can
> control TRIAC dimming with a 1000hz signal not synchronized to the zero
> crossing but none that I can divine that support the claim of actually
> deterministically providing many different dim levels without flicker.
I don't know your technical training, but evidently the breadth of that
training is sorely lacking.
> 1) His actual trigger (control) signal has a significant component of 60hz AC
> noise ("hum") and so is in fact inadvertently synchronized to the AC line
Nope. (And I cannot imagine a way that would actually ever work. ;)
> 2) His dimmer circuit skips entire half-cycles. This would happen if his
Nope.
> 3) The dimmer is in his head and hasn't been instantiated.
Nope.
Dan Lanciani
| On 28 Oct 2006 20:33:23 GMT, Dan Lanciani <ddl@danlan.*com> wrote:
| > In article <slrnek5vme.vse.Z...@sdba64.internal>, ZsdbUse1+...@Zbigfoot.Zcom.invalid (sylvan butler) writes:
| >| If I instead trigger at 1000/sec, that is a max of 4% error when it
| >| happens at random instead of synchronized to zero crossings. This error
| >| has imperceptible effect (to my eye when using incandescent lighting).
| >
| > What (not synchronized to the zero crossing) triac trigger waveform
| > will you synthesize to obtain an approximately 50% dim level?
|
| I don't know up front, that is a software calibration issue related to
| the lamp being controlled and visual perception.
|
| If you meant 50% power level rather than 50% light level,
I didn't, but indeed the 50% power level question is more appropriate
for discussion purposes as it does not require knowledge of the light
output to power mapping.
| then I would
| synth a 50% on-time, and know that with a 4% error limit I would be
| close enough. But again, that is power, not light.
Power at 50% is fine, but can you describe the actual waveform that you
would synthesize to trigger the triac?
Dan Lanciani
ddl@danlan.*com
Jon Woellhaf
> ... folks that are interested in _actually_ dimming TRIACS,
> back-to-back SCRs or SSRs based on them may be interested in a spreadsheet
> that I created about 5 years ago.
>
> http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
Thanks for posting this information. I found it very interesting.
In dimming lights in a home, theater, etc., doesn't the human's non linear
response to light intensity need to be considered?
Jon
Robert L Bass
> doesn't the human's non linear response
> to light intensity need to be considered?
If you were preprogramming the loads for power usage, yes. In real life situations the user simply dims each light to whatever
level he likes and then saves the setting as a scene.
I've worked with a number of automated lighting controllers over the years. Most allow you to preset all manner of scenes,
cross-fades, color selections, etc. Typically, the lighting designer will preset most of the scenes with specific luminaires at
approximate levels. Then the LD goes back through the scenes, fine tuning each light by eye until the scenes are as desired. It's
simpler for a home theater because there are less lamps and less variables but the process is similar.
--
Regards,
Robert L Bass
=============================>
Bass Home Electronics
941-866-1100
Marc_F_Hult
wrote in message <GPOdnU8CbooHV9XY...@comcast.com>:
I presume that you are asking about the part of the spreadsheet that predicts
the Percent Luminous Intensity of dimmed compared to undimmed. Note that the
units are in are percent (%). So what this predicts (eg) is that the luminous
intensity of two lamps dimmed to 50% (accomplished by turning the TRIAC and
lamp on at 76 degrees = 3.5 milliseconds after zero crossing) would be equal
to the luminous intensity of one lamp that is undimmed.
Human sensitivity doesn't enter to the calculation. Luminous intensity has
units of candela (previously candles) and is 1/683 watt/steradian for one
particular, specified monochromatic light. One can convert to lights of
different wavelengths using the CIE photometric curve.
Note too that the equations, graphs and table don't predict/calculate the
reduction in color temperature with reduced rms voltage. That's yet another
phenomena requiring a different equation (approximation).
Human sensitivity _would_ be a useful thing to account for depending on the
application. As a practical matter, that's what one accounts for manually 'by
eye'. One purpose of the dimmer curves is to create a response such that the
adjustment range of a slider (on a pro lighting console) or a knob (on a
wall-mounted household dimmer) is not too cramped in some places and too
insensitive in others.
With computer control, they can be used to create look-up tables to relate all
manner of things one to another empirically (by previous direct measurement).
So for example, one could create a look-up table that would make each, say,
1/8 turn seem 'twice as bright' as before (whatever 'twice' might mean to
you.. .)
... Marc
Marc_F_Hult
www.ECOntrol.org
sylvan butler
> In dimming lights in a home, theater, etc., doesn't the human's non linear
> response to light intensity need to be considered?
As Robert posted, the "practical" way is to just set the light level you
prefer. It doesn't really matter if the dimmer is passing 80% or 20%,
just so long as you can set it to get what you want.
Mathmatically, it is even more complicated than just human
non-linearities. Incandescent lamps are also non-linear, and a
mathmatically correct 50% reduction in power will reduce light far more
than 50% in every case I know of.
The whole idea of trying to relate calculated values thru a transducer
to human perception is covered by "perceptual coding." It is especially
critical in the fields of audio, photo and video digitization and
compression. No reason to digitize outside the perceivable range, and
when doing lossy compression, to save space you might as well throw away
everything inside that range that doesn't cause a perceptible
difference.
Of course, work in this area was done long before life-like digital
media was even a remote possiblity. NTSC (and PAL and SECAM) color
television all relied on humans being less sensitive to color than black
and white, so color images needed only to add a little bit of data
compared to B&W. But even before that, with color photography
perceptual differences simplified the task of reproducing color images.
And so on.
sylvan butler
For triac control I've been playing with small tables (a dozen or so
entries) which I output to the port sequentially, repeating from the
beginning every time the end is reached. If alternating 1's and 0's in
equal numbers, then it results in a fairly good square wave to the triac
(a scope makes it pretty easy to see when task switches take away
control when running under linux, or an interrupt (eg keyboard) under
DOS). Repeating a few 0's or a few 1's in unequal amounts just extends
the off time or on time, respectively, destroying the symmetry of the
square wave.
When I connect that to a "zero switching" solid-state relay, the light
has very few dim levels before it is visibly flickering.
When I use a "random switching" SSR, the behavior of the light is fine.
And of course, as expected, it works better to switch 1/0's more
frequently (faster bits per second output) rather than less frequently,
but more frequent switching does demand more CPU attention.
I've haven't tried any complex waveforms other than when experimenting
with single-bit audio output or LEDs (no triac involved). Square waves
are a natural. :) With a small bit of capacitance and a resistor
(IIRC, I was using 0.1uf and 1k), I've also been able to synth OK
looking sine, saw and triangle waves. Some of those required a lot more
than a dozen entries in the table, but could probably be optimized a
considerable amount. Then for audio, I modified a version of the linux
pc speaker driver from ancient days. It is able to reproduce
intelligible speech quality but that's where I left it.
Jon Woellhaf
considered when dimming lights and Robert, Mark, and Sylvan wrote
informative replies. Thanks to all of you.
Jon.
Dan Lanciani
| On 31 Oct 2006 23:14:34 GMT, Dan Lanciani <ddl@danlan.*com> wrote:
| > In article <slrnekfbic.bco.Z...@sdba64.internal>, ZsdbUse1+...@Zbigfoot.Zcom.invalid (sylvan butler) writes:
| >| synth a 50% on-time, and know that with a 4% error limit I would be
| >| close enough. But again, that is power, not light.
| >
| > Power at 50% is fine, but can you describe the actual waveform that you
| > would synthesize to trigger the triac?
|
| For triac control I've been playing with small tables (a dozen or so
| entries) which I output to the port sequentially, repeating from the
| beginning every time the end is reached. If alternating 1's and 0's in
| equal numbers, then it results in a fairly good square wave to the triac
| (a scope makes it pretty easy to see when task switches take away
| control when running under linux, or an interrupt (eg keyboard) under
| DOS). Repeating a few 0's or a few 1's in unequal amounts just extends
| the off time or on time, respectively, destroying the symmetry of the
| square wave.
I understand how you synthesize the waveworm but I'm still not clear on
the specific triac trigger waveform you use for 50% power. Could you
describe it in terms of frequency and duty cycle or such?
Dan Lanciani
ddl@danlan.*com
sylvan butler
> the specific triac trigger waveform you use for 50% power. Could you
> describe it in terms of frequency and duty cycle or such?
It isn't a simple wave. :)
I have not measured or attempted to calculate 50% power out of the
triac. I don't have the scope out right now, so I just played a bit
with software...
Full speed alternating on/off (a 1:1 duty cycle, which produces a fairly
nice square wave on the gate) has no obvious effect on intensity. A
full speed 1:4 (on:off) duty cycle noticably dims the light, maybe a 10%
power reduction. At full speed with a simple wave (e.g. all on then all
off for regular periods) I cannot get down to a 50% power output without
flicker -- the off times are too long.
(This system was a C633 the last time I had the scope on the output, and
at that time full speed 1:1 produced a square wave of about 150khz,
IIRC. Now it is PIII 750, but I expect that bus waits will keep the
output about the same since a k6-2/400 was also about the same.)
Crude rate limiting to approximately two samples per tick (reprogrammed
the timer to 1000 ticks per second) I can get lower power but I start
getting flicker somewhere around the 1:4 on:off ratio. I expect
interrupt overhead is becoming significant and my delay loop between my
two samples per tick is very crude.
So now I go to a sample table where I can generate more complex waves...
Full speed using a 200 sample table I get an estimated 50% power (light
very orange, but still bright enough to fill the globe) when I do a
pattern with a duty cycle of about 1:2 (on:off) somewhat randomly
distributed within the table (it was actually 64 on, 136 off). Using
the same table at 2 samples per tick (default frequency 18.x/sec)
results in very dim light, sometimes a bit of flicker.
Using a PIC it might be easier to sync with the zero-crossing and get
some determinism. I've googled a bit, and syncing a PIC seems pretty
simple. But I don't want to input that back to my PC parallel port.
Plus the real-time 120x/second is a bother. I maybe should have saved
that data table... :( Just keyed it all in directly to memory with
debug.)
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnekkfah.8g4.Z...@sdba64.internal>:
sylvan,
Thank you for taking the time to work through this on the bench. Usenet
participants and other readers will be well served by your recognition that
synchronization to the AC waveform is needed to usefully dim TRIACs.
You really shouldn't have more of a problem safely bringing the zero crossing
to the PC through a printer port input than safely controlling the TRIACS
through an output. You can use a low-voltage ( eg 120VAC:6VAC) transformer for
isolation and one of the many schematics available on the web to get a snappy
TTL signal. The isolation transformer would make the zero crossing signal even
safer than the outputs to the TRIACS especially if you aren't already using
(you should ;-) opto-isolators on the printer port outputs. As you know, the
printer port has inputs as well as outputs, so adding zero-crossing would be
very little work.
You can then use the table at
http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf to calculate the
needed deterministic delays. You may find that it helps to avoid/eliminate
disable disk accesses. With DOS systems this is simple enough to do by booting
from a floppy and making sure the transient part of the OS stays in memory so
that disk reads are not needed. Use RAM-disk for large tables/data if needed.
I've lost track of what tricks are now available to get hardware interrupts
from today's equivalents of the PC/AT's 8259 and 8254 but note that the 18.2
msec Timer interrupt ain't good enough ;-)
There are a variety of links to microcontroller-based dimmers on my web site.
Also, I have a couple of Artistic License AL4016 IC's (8051-based, not PIC,
DMX dimmers) that each dim 16 TRIACs that I'd give you for a quarter on the
dollar or so. See for complete info.
http://www.artisticlicence.com/cat11_1.htm . USB->DMX converters can be had
for $25 or so on eBay. The TRIACs and or SSRs you already have should work
fine. Email me offline if that is of interest.
HTH ... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrneki6eg.a7n.Z...@sdba64.internal>:
>On Wed, 1 Nov 2006 09:24:03 -0700, Jon Woellhaf <jonwo...@comcast.net>
wrote:
>> In dimming lights in a home, theater, etc., doesn't the human's non linear
>> response to light intensity need to be considered?
>
>As Robert posted, the "practical" way is to just set the light level you
>prefer. It doesn't really matter if the dimmer is passing 80% or 20%,
>just so long as you can set it to get what you want.
This certainly applies to the end user. But folks that actually design dimmers
might initially choose a mathematical representation of the known physics for
design purposes. (I got the equations shown on my spread sheet from Chris
Pflieger, a design engineer at www.Touchplate.com about 5 years ago.)
>Mathmatically, it is even more complicated than just human
>non-linearities. Incandescent lamps are also non-linear, and a
>mathmatically correct 50% reduction in power will reduce light far more
>than 50% in every case I know of.
From my at http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
50% dimming with respect to luminous intensity is achieved at ~76 degrees =
3.53 milliseconds delay.
50% dimming with respect to RMS voltage at ~114 degree = 5.26 milliseconds.
>The whole idea of trying to relate calculated values thru a transducer
>to human perception is covered by "perceptual coding." It is especially
>critical in the fields of audio, photo and video digitization and
>compression. No reason to digitize outside the perceivable range, and
>when doing lossy compression, to save space you might as well throw away
>everything inside that range that doesn't cause a perceptible
>difference.
But in the case of TRIAC dimmer control (see thread subject) a single byte
holds all the information needed to produce 2^8 = 256 levels *IF* one also
knows when the zero crossing occurs as is conventional. sylvan doesn't know
the z-crossing and so futilely tries/d to overcome that lack of critical data
by creating complex waveforms with large data requirements that by his
admission challenges the timely computing power of a PC.
So in sylvan's case, he has created the need for a much larger amount of
information, that indeed does need to be reduced.
But the single byte in the conventional approach is all the information that
needs to be transmitted to the dimmer, or held in a register of a
microcontroller or the latched input of a digital-to-analog (DA) converter.
Applying 'perceptual coding" to that single 8-bit byte, we could usefully
'compress' it to a 4-bit nibble to produce 16 levels if that is all that is
needed.
So, for example the table at:
http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
can be used to select values for a new, equal intensity, 16-step dimmer curve
with Full ON, Full OFF and 14 intermediate steps each causing about 6%
reduction in light intensity. This would be 'perceptually' plenty good enough
in nearly all practical home automation scenarios.
... Marc
Marc_F_Hult
www.EControl.org
Max
the intensity of a light very very slowly, without seeing any noticeable
step
in brightness (especially noticeable at the lower brightnesses) you need
each
change in time to be around 10us or so. This means for the criteria
mentioned,
you would need many hundreds of steps, likely about 500 or so. I would
consider a 100 step dimmer marginal and a 256 step minimum. But that is
just my preference :-)
Max
have two possible concerns, 1) What kind of noise would be
generated by switching that fast and 2) what kind of heat would
be generated by having your control device switching on and off
that much?
"sylvan butler" <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
news:slrnekkfah.8g4.Z...@sdba64.internal...
Robert L Bass
> Applying 'perceptual coding" to that single
> So, for example the table at:
> http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
>
> can be used to select values for a new, equal
Dave Houston
>I have done some playing around with this and found that in order to change
>the intensity of a light very very slowly, without seeing any noticeable
>step
>in brightness (especially noticeable at the lower brightnesses) you need
>each
>change in time to be around 10us or so. This means for the criteria
>mentioned,
>you would need many hundreds of steps, likely about 500 or so. I would
>consider a 100 step dimmer marginal and a 256 step minimum. But that is
>just my preference :-)
>
Sending a single DIM or BRIGHT code to an X-10 LM465 lamp module results in
an average change of about 0.662% as measured with a Kill-A-Watt (a 100W
bulb makes things simple) and with a true RMS voltmeter. 146 steps will take
the lamp from one extreme to the other. (It varies a bit with other models
of lamp modules.)
http://davehouston.net/micro-dim.htm
Using a 25W R14 lamp in a spotlight type holder, it is easy to discern
individual steps on the low end either by looking at the light projected
onto a surface or, at the very lowest levels, looking at the filament
itself.
With a 100W bulb in a standard table lamp, individual 0.662% steps result in
larger increments in light level that, again, can be discerned by looking at
the light hitting the ceiling or looking directly at the filament at very
low levels.
I think that most people would not find the changes annoying - they are not
readily perceived unless you are watching for them and, even then, only if
the steps are fairly close in time. But, it will depend on the eye of the
beholder.
http://davehouston.net
http://tech.groups.yahoo.com/group/roZetta/
roZetta-...@yahoogroups.com
Marc_F_Hult
A TRIAC controlling 60hz AC can only be switched on (it turns _itself_ off) at
a maximum rate of 120 hz no matter what the input. So regardless of the
frequency of the input, and regardless of the waveform, there will be a
maximum number of 120 transitions per second. (IOW, what sylvan is trying to
do does not actually work.)
The maximum output slew rate (and potential noise) occurs when the AC waveform
is at 90 and 270 degrees (= peak voltage of 170 volts, rms output voltage for
the entire half cycle = 85Vrms, and ~33% output for typical tungsten lamp
compared to full output). These calculations assume 120VAC and neglect the
band-gap and IR drop (loss owing to resistance) of about 1-1/2 volts.
See http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
... Marc
Marc_F_Hult
www.EControl.org
On Thu, 02 Nov 2006 23:30:07 GMT, "Max" <nos...@hotmail.com> wrote in message
<3cv2h.78624$E67.37158@clgrps13>:
Marc_F_Hult
What I meant would have been clearer had I written "scene" instead of
"scenario" ;-) Oh Strunk and White -- where art you? )
In terms or *static* _scenes_ (WatchingTV, GoodNight, Entertainment, AllON,
AllOFF) 16 different levels seem plenty. I know I could get by jist fine with
4 or 5 intermediate levels.
But as Robert wrote earlier in the thread, and you point out here, dynamic
(changing) scenes such as those used in theatre and concerts need more levels.
(Note though, that 256 levels are that all the great majority of professional
theatres and other entertainment venues have, so if 256 is not enough, the
majority of performances world wide are unsatisfactory ;-)
I realize now that fade rate may be something that is of interest to others in
HA, and for that purpose, 16 levels may indeed be inadequate depending on
one's preferences.
... Marc
Marc_F_Hult
www.ECOntrol.org
On Thu, 02 Nov 2006 23:25:30 GMT, "Max" <nos...@hotmail.com> wrote in
message <K7v2h.78621$E67.6635@clgrps13>:
Robert L Bass
> you point out here, dynamic (changing) scenes
> such as those used in theatre and concerts
True, but since many HA applications also encompass HT design, it's pertinent to the discussion.
> (Note though, that 256 levels are that all the
> great majority of professional theatres and
> other entertainment venues have, so if 256
> is not enough, the majority of performances
> world wide are unsatisfactory ;-)
>
> I realize now that fade rate may be something
> that is of interest to others in HA, and for that
> purpose, 16 levels may indeed be inadequate
> depending on one's preferences.
Completely agree, Marc. I should also point out for the sake of others that fade rate is independent of the number of available
dimming steps between ON and OFF. I recall a *scene* we set up during a Christmas play one year. The scene called for a single
fixture projecting through a star shaped gobo to create the image of a brilliant star slowly appearing in the "sky". A Source IV
lamp was programmed to fade from OFF to full on over the course of several minutes. During the first minute or so it looked like
all the other stars in the background. As the actors moved about the stage and the scene progressed, the "Christmas Star" slowly
became the most brilliant light in the scene. It was interesting listening to the ooohs and aaahs as different people noticed what
was happening.
The system stepped the dimmer through 255 levels. During programming I usually "wrote" the scenes using 5% increments (100% on, 55%
ON, etc.). Once the scenes for a given performance were blocked in I would go through the script, adjusting each fixture with a
wheel -- paying no attention at all to the actual output levels -- until I got the visual effects I wanted. Later, after the
scenery and backdrops were done, I'd redo almost every scene -- again using the wheel and paying no attention to levels.
The above is pretty much how all small-scale (and many large scale) lighting designs are done. I realize that this is borderline
OT, but thought it might be interesting to a few folks anyway.
Max
switched
at a much higher frequency on and off during any point in the ctcle. I
imagine this
would work to give you some lesser power out. All you would be doing is
chopping
the AC into really small chunks and they would average over the entire
wave(s).
I think the problem would be noise and heat.
"Marc_F_Hult" <MFH...@nothydrologistnot.com> wrote in message
news:kurmk2dodtre59igl...@4ax.com...
sylvan butler
> Sending a single DIM or BRIGHT code to an X-10 LM465 lamp module results in
When you say "single DIM or BRIGHT" are you referring to a micro-dim (as
sendable by the CM11) or a single press of the button on a mini- or
maxi-controller (which is the normal X10 standard of a command and a
repeat as seen on the power line)?
> an average change of about 0.662% as measured with a Kill-A-Watt (a 100W
> bulb makes things simple) and with a true RMS voltmeter. 146 steps will take
That sounds like a micro-dim...
sylvan butler
> I assumed he was talking about some device other than a triac that
> could be switched at a much higher frequency on and off during any
> point in the ctcle. I
That gets a bit ugly (and more expensive) if you intend to control
120vac. (Of course, one could rectify the 120vac to create ca. 170vdc
and use MOSFETs...)
> imagine this would work to give you some lesser power out. All you
Yup.
> would be doing is chopping the AC into really small chunks and they
> would average over the entire wave(s).
that's pretty much how it would work. But it is a lot easier with D.C.
You would have to be really motivated to do it with A.C.
> I think the problem would be noise and heat.
Heat is not much of a problem compared to older dimmer technologies.
Switching on/off means the switch is either conducting (very low volt
drop hence power loss) or not conducting (essentially no leakage
current, thus no power loss). I do have some 40amp SSRs that require a
pretty substantial heat sink for full power. But you figure even a
small voltage drop at 40amps means a lot of waste power. Running 20amps
and mounted to a metal box they don't get noticably warm.
noise, OTOH... Electrical noise can be a problem if switching large
loads, inductive or capacitive loads, or attempting to pass fast pulses
thru long wires. As marc pointed out, with triac switching 60hz A.C.,
it just isn't that fast. However, if switching large loads you prefer
to not "dim" them, and to avoid electrical noise (and sometimes even
bigger problems) you usually sychronize the turn on and turn off at the
zerocrossing. But even a typical home-use dimmer for a few hundred
watts will generate electrical noise. The standard practice is to put
in a small choke (inductor) to quiet it down.
Of course, if you meant accoustic noise, well, mechanical relays don't
switch that fast either. :) More seriously, sometimes you can find a
resonant frequency of the filaments in the lights and hear a pretty good
hum. In practice it doesn't happen very seriously, very often.
sylvan butler
> On Wed, 1 Nov 2006 15:04:00 -0700, sylvan butler
><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
><slrneki6eg.a7n.Z...@sdba64.internal>:
>
>>On Wed, 1 Nov 2006 09:24:03 -0700, Jon Woellhaf <jonwo...@comcast.net>
> wrote:
>>> In dimming lights in a home, theater, etc., doesn't the human's non linear
>>> response to light intensity need to be considered?
>>
>>As Robert posted, the "practical" way is to just set the light level you
>>prefer. It doesn't really matter if the dimmer is passing 80% or 20%,
>>just so long as you can set it to get what you want.
>
> This certainly applies to the end user. But folks that actually design dimmers
> might initially choose a mathematical representation of the known physics for
> design purposes. (I got the equations shown on my spread sheet from Chris
yeah, back in the days when the dim level was controlled by a variable
resistor (even when controlling a triac) it was handy to know the value
of that resistor and the floor and ceiling values of the total
resistance.
> From my at http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf
>
> 50% dimming with respect to luminous intensity is achieved at ~76 degrees =
> 3.53 milliseconds delay.
And that will vary somewhat depending on differences in the actual
incandescent light (hardware).
> But in the case of TRIAC dimmer control (see thread subject) a single byte
> holds all the information needed to produce 2^8 = 256 levels
An 8-bit byte always does.
> by creating complex waveforms with large data requirements that by his
> admission challenges the timely computing power of a PC.
Marc, I neither said nor alluded to any such thing, and I thank you
kindly to not put words into my mouth.
> Applying 'perceptual coding" to that single 8-bit byte, we could usefully
> 'compress' it to a 4-bit nibble to produce 16 levels if that is all that is
> needed.
That is not perceptual coding and is not in any way related to it.
> can be used to select values for a new, equal intensity, 16-step dimmer curve
> with Full ON, Full OFF and 14 intermediate steps each causing about 6%
> reduction in light intensity.
You certainly do not want "equal intensity" and equal "6% reduction in
light intensity" in your steps. If you actually implemented a dimmer
that way, the bottom steps (starting from dark) would appear
significantly bigger jumps than the top steps (approaching full-bright).
THAT is human perception.
Perceptual coding takes place at a lower level in the design, realizing
that human vision can detect a very small change from dark (no lumens)
to some light (lumens), but cannot detect an equal change in lumens from
bright to brighter. Thus perceptual coding is used so that whether your
dimmer has 16 steps or 256 steps or 65536 steps, the perception of
brightness is uniform at each step even though the increase in light
intensity between each step grows MUCH larger as the light gets
brighter.
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrneknip8.p3a.Z...@sdba64.internal>:
>On Fri, 03 Nov 2006 21:44:31 GMT, Max <nos...@hotmail.com> wrote:
>> I assumed he was talking about some device other than a triac that
>> could be switched at a much higher frequency on and off during any
>> point in the ctcle. I
>
>That gets a bit ugly (and more expensive) if you intend to control
>120vac. (Of course, one could rectify the 120vac to create ca. 170vdc
>and use MOSFETs...)
>
>> imagine this would work to give you some lesser power out. All you
>
>Yup.
>
>> would be doing is chopping the AC into really small chunks and they
>> would average over the entire wave(s).
>
>that's pretty much how it would work. But it is a lot easier with D.C.
>You would have to be really motivated to do it with A.C.
There you go again ;-)
Powering lamps designed for 120VAC with rectified 170 VDC (= 170 VRMS) as you
suggest is problematic because if the circuit were to ever stop chopping, the
lamp would burn out right quick.
So when MOSFETs are used as the dimming control elements for lamps with an AC
power source, the lamps are powered by AC, *not* DC. (and the circuit is
elegant, not "ugly", in my personal opinion).
It isn't any harder to do it right; it requires the essentially the same
components as what you suggest and so is not intrinsically "more expensive" as
you claim.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrneknjm2.p3a.Z...@sdba64.internal>:
>On Thu, 02 Nov 2006 15:38:23 -0500, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>>This certainly applies to the end user. But folks that actually design
>>dimmers might initially choose a mathematical representation of the known
>>physics for design purposes. (I got the equations shown on my spread sheet
>>from Chris
>
>yeah, back in the days when the dim level was controlled by a variable
>resistor (even when controlling a triac) it was handy to know the value
>of that resistor and the floor and ceiling values of the total
>resistance.
And in the case of TRIAC based dimmers, it would be handy for you to see the
underlying equations so that you would know that what you claimed in this
newsgroup in umpteen posts simply does not work and that despite your claim to
the contrary, there is in fact an "easily calculable relationship to dim
level". See my the equations in the url in the line below.
>>n
>> 50% dimming with respect to luminous intensity is achieved at ~76 degrees =
>> 3.53 milliseconds delay.
>
>And that will vary somewhat depending on differences in the actual
>incandescent light (hardware).
>
>> But in the case of TRIAC dimmer control (see thread subject) a single byte
>> holds all the information needed to produce 2^8 = 256 levels
>
>An 8-bit byte always does.
Here sylvan snips out the part of my sentence above that makes his quip above
so silly and relates to the critical importance of timing, namely:
*IF* one also knows when the zero crossing occurs as is conventional.
sylvan doesn't know the z-crossing and so futilely tries/d to
overcome that lack of critical data .."
He fantasized that with complex waveforms and (newsgroup post by newsgroup)
increasing frequencies and complexity, he could make a TRIAC dim evenly
without skipping half-cycles and without a timing reference to the
zero-crossing. But he couldn't despite the fact that he claimed that he had.
>> by creating complex waveforms with large data requirements that by his
>> admission challenges the timely computing power of a PC.
>
>Marc, I neither said nor alluded to any such thing, and I thank you
>kindly to not put words into my mouth.
I don't. You gave up using the 18.2 timer. Then you gave up trying to time
using progressively higher and higher frequencies. Then you finally broke down
and kinda hint that you would have to time it with reference to the
zero-crossing because no matter how what kilo/mega/gigahertz frequency you
tried, it didn't work. "Timely". Read what I wrote because it is at the core
of why what you have written flat out does not work. I thank you kindly for
getting that part right finally and ending your obfuscation. When you finally
stop dodging and misquoting, it will be easier to know what you actually mean
to say.
>> Applying 'perceptual coding" to that single 8-bit byte, we could usefully
>> 'compress' it to a 4-bit nibble to produce 16 levels if that is all that is
>> needed.
>That is not perceptual coding and is not in any way related to it.
Of course it is. When one compresses an 8-bit linear curve to a 4-bit
square-law curve, one uses fewer bits and incorporates the non-linear way in
which humans perceive light. This is an excellent example of perceptual coding
(square-law curves) that has been around for decades.
>> can be used to select values for a new, equal intensity, 16-step dimmer
>> curve with Full ON, Full OFF and 14 intermediate steps each causing about
>> 6% reduction in light intensity.
>
>You certainly do not want "equal intensity" and equal "6% reduction in
>light intensity" in your steps. If you actually implemented a dimmer
>that way, the bottom steps (starting from dark) would appear
>significantly bigger jumps than the top steps (approaching full-bright).
Why don't I ? Do you think that log is intrinsically better than linear? For
what purpose? A linear curve is in fact one of the conventional choices in
quantitatively calibrated commercial dimmers. See the AL4016 dimmer chip at
http://www.artisticlicence.com/cat11_1.htm that I cited previously.
>THAT is human perception.
Huh? WHAT is "human perception"? Having spent many years with densitometers
and calibrated light meters, and different films and developers and toners and
papers, I can assert unequivocally that a strict log curve is *not* what is
always aesthetically pleasing or convincing or realistic or desired in part
because of the time-dependence of the logarithmic human perception of light.
Perhaps if you were more knowledgeable, you would write that a different,
equally valid, also quantitative, also commercially available curve, that
incorporates a different approximation to the way humans perceive light, is
one that obeys a square-law, such as the AL4017 chip -- also available from
http://www.artisticlicence.com/cat11_1.htm
>Perceptual coding takes place at a lower level in the design,
Lower than what? Lower than the basic physics of electron flow that you got
flat out wrong?
If you know the physics, and can write and use the equations, the "perceptual
coding" could in fact be done at the last moment, on the fly, by choosing a
different equation or coefficient immediately before sending the ON
instruction to the TRIAC.
I can transform the curves shown in my spreadsheet into most any curve that is
wanted: log, square-law, linear, s-shaped, and any combination of them. I can
do this despite the fact that you have asserted that there is no ready
mathematical relationship, because you are also wrong when you assert that.
And practical dimmer curves often follow more than one 'law' for practical
reasons. One common need is for a preheat-level that can be incorporated into
the curve. In my case, I want a flat part at the top of the voltage curve to
close the contact of a mechanical relay in order to effectively switch the
TRIAC out of circuit at 100% on and I want that to be an un-missable target
when physically rotating a knob or moving a slider.
Similarly with the bottom of the curve. I do *not^ want a barely visible low
level (i.e, the logarithmic curve you insist I should want) in a real light
source in a real room because with incandescent lights, that is inordinately
wasteful of electricity.
So I do *not* want a log curve at low levels as you insist I should. It is
much more efficient to switch to a lower wattage lamp for low levels and it is
an outright requirement if one wants anything resembling 'white" (not orange)
light using incandescent lamps.
> realizing
I realize, you realize, he, she, or it (Already!) realizes.
>that human vision can detect a very small change from dark (no lumens)
>to some light (lumens), but cannot detect an equal change in lumens from
>bright to brighter. Thus perceptual coding is used so that whether your
>dimmer has 16 steps or 256 steps or 65536 steps, the perception of
>brightness is uniform at each step even though the increase in light
>intensity between each step grows MUCH larger as the light gets
>brighter
Duh ... That's what effectively part of what a square-law dimmer curve
addresses. So what you are saying is that you would prefer a AL4017 over a
AL4016.
You pontificate in a way that makes it appear that you don't realize that
folks accomplished and have made commercially available long ago what you are
still grappling with in theoretical terms while using smoke and mirrors to
avoid the reality that your dimmer design flat out doesn't work because you
are ignorant of the basic physics.
Seems to me that you have interesting ideas that are usefully discussed in
this newsgroup. Thank you for that.
But do try to learn something in the process and do help us fix mistakes or
misstatements rather than trying to cover them up.
Take care ... Marc
Marc_F_Hult
www.ECOntrol.org
sylvan butler
> On Fri, 3 Nov 2006 16:05:12 -0700, sylvan butler
><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
><slrneknip8.p3a.Z...@sdba64.internal>:
>>> would average over the entire wave(s).
>>
>>that's pretty much how it would work. But it is a lot easier with D.C.
>>You would have to be really motivated to do it with A.C.
>
> There you go again ;-)
>
> Powering lamps designed for 120VAC with rectified 170 VDC (= 170 VRMS) as you
> suggest is problematic because if the circuit were to ever stop chopping, the
> lamp would burn out right quick.
You misunderstand.
120vac sine wave == about +/-170v peak. I was not suggesting creating a
filtered 170vdc supply, just rectifying the 120vac sine wave.
You won't need a chopper, because it isn't pure D.C. steady at 170v, it
is just the lower (negative going) half of the wave flopped into the
gaps on the top. Still goes up to 170v and down to 0v, 120 times per
second, it just no longer alternates, hence it is D.C. (pulsating).
> So when MOSFETs are used as the dimming control elements for lamps with an AC
> power source, the lamps are powered by AC, *not* DC. (and the circuit is
So my Athlon 64 is powered by A.C. because I plug it into an A.C. power
source? Sure, in some sense, but not practically correct. Put a scope
on the power leads, the Athlon is definiteliy powered by D.C. and if you
rectify the incoming A.C., you no longer have A.C.
It is only A.C. if it alternates polarity. That is what Alternating
Current means.
sylvan butler
[a bunch of innuendo and lies wrapped around a strawman that I
supposedly said I wanted log curve after Marc supposedly did not say he
wanted equal intensity steps]
This is truly hopeless. It is also rather funny that you bring a
densitometer and film and toners and papers into this thread after I
just spent a week with Dr Hunt (no, I'm not on a first-name basis with
him, maybe you are). It is not even funny how much I got from a
lunchtime 5 minute conversation with him re. light and color
reproduction, vs how much time I've spent repeating myself for you.
But hey, you did a lot better at this than would I at hydrology!
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnektarg.fbp.Z...@sdba64.internal>:
>On Sat, 04 Nov 2006 10:43:14 -0500, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>
>[a bunch of innuendo and lies wrapped around a strawman that I
>supposedly said I wanted log curve after Marc supposedly did not say he
>wanted equal intensity steps]
hmmm ... We don't understand each other, do we?
Here's one conventional way organizing what we have been discussing:
1) Real World System, represented by --->
2) Conceptual Model of real world (typically a simplification) --->
3) Simulation Model --->
3a) Mathematical Model(exact or approximate) typically as equations
AND(OR)
3b) Physical Model
4) Solutions
4a) Math: Numerical results (often themselves approximations)
AND(OR)
4b) Physical: Observed results
5) Applications,typically choosing from a range of legitimate solutions
(4a,4b) which are typically approximations of the Real World (1)
The solutions (4a) and(or) (4b) can be compared to the Real World (1) to
assess how close they are to reality. How close is "close enough" depends on
the objective (purpose), is often subjective, and is assessed in
Applications(step 5).
We are in agreement through step (1) ( I think ;-)
My Conceptual Model (2) of the physics of how TRIACS work was/is correct --
albeit simplified because, eg, it neglects band-gap losses.
The equations (3a) I use/d are also approximations, although the solutions
to the equations are themselves exact within rounding error. (For complex
systems, the solutions to the equations are often themselves approximation.)
These equations can be used to create a suite of solutions (linear,
square-law, log dimmer curves etc). Depending on the purpose, each may or
may not be "close enough".
((There are no straw men here. These are each -- including linear equal-step
-- legitimate solutions depending on the purpose. Sylvan wrote: "Marc
supposedly did not say he wanted equal intensity step" ;-) You also wrote: I
[sylvan] supposedly said I wanted log curve" -- which was the approximation
closest to you stated qualitative description of human perception of
light.))
But sylvan's/your Conceptual Model (2) of how TRIACS work was flat-out
wrong.
And you were unable to provide mathematical descriptions as either waveforms
or equations (3a & 4a See your non-responsive answers to Dan's simple
questions.
And because your conceptual model (2) of how TRIACS work was incorrect,
--> your Physical Model (3b) was _also_ incorrect (unsynchronized control
of a TRIAC gate)
--> your Physical Solution (4b) was _also_ incorrect (you could never
create a non-flickering 50% of power, voltage, light output or
anything else).
Although your 'Solutions' (4b) didn't actually didn't work, you had in mind
what you wanted the results to look like and apparently believed that
'perceptual coding' in (3) was somehow going to fix the problem with you. It
didn't, couldn't, and never can (except by chance) because the physics in
the conceptual model are more fundamental than the conceptual model (See my
previous comments to this effect.)
>This is truly hopeless. It is also rather funny that you bring a
>densitometer and film and toners and papers into this thread after I
>just spent a week with Dr Hunt (no, I'm not on a first-name basis with
>him, maybe you are). It is not even funny how much I got from a
>lunchtime 5 minute conversation with him re. light and color
>reproduction, vs how much time I've spent repeating myself for you.
Actually, we've accomplished the main objective quite completely.
I have been persistent in countering your unproven claims that you can make
a TRIAC dim evenly without synchronizing to the zero-crossing. That is now
clear, with or without your cooperation, and hopefully others will not waste
_their_ time attempting your futile approach. IOW, this is not about sylvan.
It's about helping others.
Although you too presumably benefited: you could spend the rest of your life
putzing with perceptual coding and *never* get the TRIACS to work with your
approach. You did larn that, right? ;-)
That we might also benefit more from this overall discussion is part of the
reason I spent time explaining my approach to things in the paragraphs
above.
>But hey, you did a lot better at this than would I at hydrology!
What I outlined above is one scientific approach, not a geologic, or
hydrologic one. Physical modeling (your apparent approach under this
organizational scheme) is neither more or less valid than mathematical
modeling. Both needed to be checked (calibrated, validated, refined, choose
your action/verb) with the Real World (1).
What is your field ( 'area of expertise', 'core competency') ?
I _do_ hope this helps ... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
<ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
<slrnekt5ln.fbp.Z...@sdba64.internal>:
>On Fri, 03 Nov 2006 23:27:48 -0500, Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote:
>> On Fri, 3 Nov 2006 16:05:12 -0700, sylvan butler
>><ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
>><slrneknip8.p3a.Z...@sdba64.internal>:
>>>> would be doing is chopping the AC into really small chunks and they
>>>> would average over the entire wave(s).
>>>
>>>that's pretty much how it would work. But it is a lot easier with D.C.
>>>You would have to be really motivated to do it with A.C.
>>
>> There you go again ;-)
>>
>> Powering lamps designed for 120VAC with rectified 170 VDC (= 170 VRMS) as
>> you suggest is problematic because if the circuit were to ever stop
>> chopping, the lamp would burn out right quick.
>
>You misunderstand.
>
>120vac sine wave == about +/-170v peak. I was not suggesting creating a
>filtered 170vdc supply, just rectifying the 120vac sine wave.
Of course you did. sylvan wrote:
"That gets a bit ugly (and more expensive) if you intend to
control 120vac. (Of course, one could rectify the 120vac to
create ca. 170vdc and use MOSFETs...)
So you did in fact clearly and unambiguously "suggest[] creating a
filtered 170vdc supply". It was this statement that I responded to. The
record is crystal clear.
Can you peddle forwards as well as backwards?
... Marc
Marc_F_hult
www.ECOntrol.org
Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote in message
<rcpuk2lj8ill51hg0...@4ax.com>:
>didn't, couldn't, and never can (except by chance) because the physics in
>the conceptual model are more fundamental than the conceptual model (See m
^^^^^^^^^^^^^^^
Should say: "because the physics in the Conceptual Model (2) are more
fundamental to success than the particular Simulation Model (3) chosen"
...Marc
Marc_F_Hult
www.ECOntrol.org
Robert L Bass
"Marc_F_Hult" <MFH...@nothydrologistnot.com> wrote in message news:ulquk2d4riar7qn3p...@4ax.com...
Hmm... "Fundamentalist science!" Now there's a concept you won't hear very often. :^)
Marc_F_Hult
<MFH...@nothydrologistnot.com> wrote in message
<nkquk25nuvphhnqm9...@4ax.com>:
In forty years of designing electronic circuits, I've never seen the
shorthand "ca." to mean "rectified but not filtered". But I suppose that is
what you did mean. (I misunderstood you and yes, I can back peddle too ...
;-)
If one "[rectif[ies] the 120VAC to create ca. 170vdc and use MOSFETS", and
don't also "filter" (add capacitance), you get 120Vrms which has a peak
voltage of 170v with 100% ripple. And depending on how this is coupled and
grounded (or not) it is either DC or AC. In this case, with respect to earth
ground, it is DC sensu stricto (your point).
In the typical 120VAC circuit using MOSFETs for control of AC lamps, the
lamps do see ~120VAC-(2 x 0.65)VAC -- not DC which is what I understood you
to imply.
... Marc
Marc_F_Hult
www.ECOntrol.org
Marc_F_Hult
wrote in message <9MCdncz9H4Ak8dLY...@comcast.com>:
>
>"Marc_F_Hult" <MFH...@nothydrologistnot.com> wrote in message
news:ulquk2d4riar7qn3p...@4ax.com...
>> On Mon, 06 Nov 2006 11:53:29 -0500, Marc_F_Hult
>> <MFH...@nothydrologistnot.com> wrote in message
>> <rcpuk2lj8ill51hg0...@4ax.com>:
>>
>>
>>>didn't, couldn't, and never can (except by chance) because the physics in
>>>the conceptual model are more fundamental than the conceptual model (See
>> ^^^^^^^^^^^^^^^
>> Should say: "because the physics in the Conceptual Model (2) are more
>> fundamental to success than the particular Simulation Model (3) chosen"
>
>Hmm... "Fundamentalist science!" Now there's a concept you won't hear very
often. :^)
Ouch! ;-)
You trying to 'get me going'?
(We've been long-winded enough in these threads ...)
More seriously: Very glad to see you that you are maintaining good humor.
Get well ..Marc
Marc_F_Hult
www.EControl.org
Robert L Bass
>> there's a concept you won't hear very
>> often. :^)
>
> Ouch! ;-)
>
> You trying to 'get me going'?
> (We've been long-winded enough
> in these threads ...)
>
> More seriously: Very glad to see
> you that you are maintaining good
> humor.
>
> Get well ..Marc
Thanks, Marc. I've been feeling progressively
better the past few days. I even took my
sweetheart out for a ride on my bike yesterday.
We visited Venice Beach, enjoyed a meal on
the pier watching all the snow birds play with
their grand-kiddies in the sand. Life is great!
Next week I go in for my final chemo session.
Then it will be two more weeks of misery before
I'm finally done with this stuff. I'm planning a
cross-country flight in a "Tiger" three weeks
hence just to celebrate!
sylvan butler
clearly and unambiguously "suggest"?? LOL.
Did not. :)
>> It was this statement that I responded to. The
>>record is crystal clear.
Indeed it is...
> In forty years of designing electronic circuits,
Forty years... So maybe you also started with vacuum tubes? I tried to
convice the professor they were irrelevent, but he wouldn't hear it.
Still have never used that since then...
> I've never seen the
> shorthand "ca." to mean "rectified but not filtered".
"ca." means "circa" as in "approximately." As in, unless you know the
exact A.C. peak voltage, and knowing that utility A.C. delivery
tolerance is on the order of 10's of volts (RMS), and also not knowing
the current vs Vf curve on the rectifier and of course not knowing the
load, there really was no point is being any more precise than
"approximately 170vdc."
> But I suppose that is what you did mean.
Yes, we've seen how you continually suppose the worst.
> If one "[rectif[ies] the 120VAC to create ca. 170vdc and use MOSFETS", and
> don't also "filter" (add capacitance), you get 120Vrms which has a peak
> voltage of 170v with 100% ripple. And depending on how this is coupled and
> grounded (or not) it is either DC or AC. In this case, with respect to earth
> ground, it is DC sensu stricto (your point).
Thank you, in the strictest sense.
sylvan butler
> But sylvan's/your Conceptual Model (2) of how TRIACS work was flat-out
> wrong.
According to your supposition of my model...
> And you were unable to provide mathematical descriptions as either waveforms
> or equations (3a & 4a See your non-responsive answers to Dan's simple
> questions.
Simple question without a simple answer. A square wave is hard enough
to describe mathmatically, but when it has varying on and off times, the
math becomes more ugly than I care to deal with. It is easier to
describe algorithmically, which I attempted.
> didn't, couldn't, and never can (except by chance) because the physics in
Isn't it entertaining how much has been discovered "by chance" and
practiced successfully for many years before the physics were understood
and mathmatically described... Oh, wait, we are still trying to define
many natural processes as we discover the previous formula did not
describe the details visible under improved observation.
> Although you too presumably benefited: you could spend the rest of your life
> putzing with perceptual coding and *never* get the TRIACS to work with your
> approach. You did larn that, right? ;-)
As I said, it'd probably be easier with the zero-crossing sync.
> What is your field ( 'area of expertise', 'core competency') ?
Professionally I guess you'd call me a software engineer or something
like that, but that's only a few small facets.
I started playing with electricity before I could walk, computer stuff
starting in 1976, and I've been online since 1982 when a friend working
in a government lab created a gateway between his home BBS and the
internet in his lab. I started college to get the sheep skin saying I
knew electronics but found I liked the computer classes more. Now I
have degrees in computer systems and computer science. Doing grounds
maintenance and sprinkler system repair+installation plus a bit of
warehouse management paid my way thru school (until I got my first
software gig), so I graduated with good grades, a wife, no debt and
money in the bank. And sometimes I think that was rather stupid, if I'd
rented an expensive apartment and bought a new car I'd have qualified
for government handouts to pay for it all... But oh well.
Non-professionally I've been known to do auto mechanics; home-related
construction and repairs from framing on up including plumbing,
electrical and HVAC; technical theatre; alternative energy systems
(solar PV, thermal and wind); and yes, still the landscaping and a bit
of electronics. I've never met a tool I didn't like. (All of my
grandparents were college graduates, grandfathers were independent
farmers who built their own homes and took care of everything
themselves. I suppose I inherited a bit of that.)
Now I'm living on a hobby ranch with cows and chickens and four boys so I have
also mucked out a stall and changed a diaper or two before the oldest learned
how and when the misses wasn't available (she's a good one, let's me get away
with a lot). I'm also a "Tech Plus" (too lazy to take the General and Am-Extra
tests), and am NRA life (first member in my family) though I prefer GOA and
JPFO (no I'm not Jewish).
Specialization is for insects. (from R.H. in his good days) The only
problem is time to avoid it. But when I hire someone else it has always
turned out no better than acceptable and usually worse. So I usually
don't. Wondering if I should go into law or medicine next.
Still prefer to hire someone to do the butchering for me...
And all that is pretty much how I think of "me" at the moment.
Concluding thought for the day after elections:
"That government is best which governs not at all." (Henry David Thoreau)
AIMatrix
"sylvan butler" <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
I am the OP and been following this post into the ground. Why reinvent the
wheel, if not for just trying, its all been done before.
Anyway I went with Light-O-Rama. The clincher was the new support for X10
devices witch I was all ready using so I can still use them for the slow
stuff (1 min. or more) and the Light-O-Rama controllers for the fast stuff.
The prices are reasonable.
The program with coreographing for music is $100 and is well worth it. The
controllers are cheep considering. The high power 16 channel Kit is $160,
that's $10 per channel, as cheep as X10 but faster with more power. So for
$300 I am on my way to dancing lights.
The posters that have kept this thread going have wasted more than that in
there time and nothing was developed yet.
Thru out next year I will buy more kits and make more controllers until all
30,000 of my lights are on Light-O-Rama and I will not have to worry about
the zero crossing optimum frequency of a random program.
Andy
Marc_F_Hult
in message <YCt6h.7093$bj1.41@trndny05>:
>
>"sylvan butler" <ZsdbUse1+...@Zbigfoot.Zcom.invalid> wrote in message
>news:slrnel4ke1.dqe.Z...@sdba64.internal...
>I am the OP and been following this post into the ground. Why reinvent the
>wheel, if not for just trying, its all been done before.
>Anyway I went with Light-O-Rama. The clincher was the new support for X10
>devices witch I was all ready using so I can still use them for the slow
>stuff (1 min. or more) and the Light-O-Rama controllers for the fast stuff.
>The prices are reasonable.
>The program with coreographing for music is $100 and is well worth it. The
>controllers are cheep considering. The high power 16 channel Kit is $160,
>that's $10 per channel, as cheep as X10 but faster with more power. So for
>$300 I am on my way to dancing lights.
>
>The posters that have kept this thread going have wasted more than that in
>there time and nothing was developed yet.
>
>Thru out next year I will buy more kits and make more controllers until all
>30,000 of my lights are on Light-O-Rama and I will not have to worry about
>the zero crossing optimum frequency of a random program.
>
>Andy
Well said ;-)
(It should be apparent that the reason for my extending/participating in
this discussion is to alert other folks that what Sylvan has proposed for
controlling TRIACS simply will not work. Nor will his approach to using
MOSFETs which I will explain as time permits. IOW, the intention has been to
minimize the damage to the usefulness and credibility of information in
comp.home.automation caused by sylvan's proposed electrical alchemy.)
+++++++++
I see no hint at www.lightorama.com that the Light-O-Rama equipment is
UL-listed. Perhaps I just missed it, but if it isn't, it wouldn't meet local
code in many/most US jurisdictions. This may not pertain to your situation,
but it could to many folks. It would be unfortunate to have a 30,000 light
setup dimmed to dark.
... Marc
Marc_F_Hult
www.ECOntrol.org
AIMatrix
light controllers are considered "hobbyist"
like the kits I am buying.Plug them into professionally installed outlets
and you are good to go. Andy