Enclosures, paint and heat dissipation.
Roberto Waltman
A post in the TrimSlice forum [a] regarding the operating temperature
of the device mentions that the "really nice nickel plated case" has
an emissivity of about .03, while black epoxy paint has an emissivity
of 0.89 with the expected benefits on cooling. [b]
Is there a paint specifically designed to improve heat dissipation
that is available in small quantities to the electronics homebuilder /
hobbyist?
If so, names/brands?
Thanks,
[a] http://www.trimslice.com/forum/
[b]
http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
--
Roberto Waltman
[ Please reply to the group.
Return address is invalid ]
Tim Wescott
> A post in the TrimSlice forum [a] regarding the operating temperature of
> the device mentions that the "really nice nickel plated case" has an
> emissivity of about .03, while black epoxy paint has an emissivity of
> 0.89 with the expected benefits on cooling. [b]
>
> Is there a paint specifically designed to improve heat dissipation that
> is available in small quantities to the electronics homebuilder /
> hobbyist?
> If so, names/brands?
>
> Thanks,
>
> [a] http://www.trimslice.com/forum/
> [b]
> http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
Not that I know of. But if it looks flat black, chances are it's got
good emissivity. Or, to rephrase that: if it's got good even emissivity
in visible light, chances are it has good even emissivity across the
spectrum.
Grant Edwards
Is radiative cooling from a case even significant compared to
conducted/convenctive cooling?
Isn't a layer of epoxy paint on an aluminum case going to
significantly increase the thermal resistance?
--
Grant Edwards grant.b.edwards Yow! I like the way ONLY
at their mouths move ... They
gmail.com look like DYING OYSTERS
Roberto Waltman
>Is radiative cooling from a case even significant compared to
>conducted/convenctive cooling?
Good question, found the following:
http://www.electronics-cooling.com/2001/02/dont-underestimate-radiation-in-electronic-cooling/
www.engineering.uiowa.edu/~becker/documents.dir/JEP1991.pdf
>Isn't a layer of epoxy paint on an aluminum case going to
>significantly increase the thermal resistance?
Ditto. Increase, yes. By how much? Relevant or not?
lang...@fonz.dk
> Grant Edwards wrote:
> >Is radiative cooling from a case even significant compared to
> >conducted/convenctive cooling?
>
>
> >Isn't a layer of epoxy paint on an aluminum case going to
> >significantly increase the thermal resistance?
>
> Ditto. Increase, yes. By how much? Relevant or not?
> --
one of the first hits on google was this:
http://www.candlepowerforums.com/vb/showthread.php?143193-Flashlights-Polished-vs.-Coated
-Lasse
Roberto Waltman
>one of the first hits on google was this:
>http://www.candlepowerforums.com/vb/showthread.php?143193-Flashlights-Polished-vs.-Coated
Thanks - What search pattern did you use?
Ian Field
"Roberto Waltman" <use...@rwaltman.com> wrote in message
news:htj7575tnt4mk4to5...@4ax.com...
>
> A post in the TrimSlice forum [a] regarding the operating temperature
> of the device mentions that the "really nice nickel plated case" has
> an emissivity of about .03, while black epoxy paint has an emissivity
> of 0.89 with the expected benefits on cooling. [b]
>
> Is there a paint specifically designed to improve heat dissipation
> that is available in small quantities to the electronics homebuilder /
> hobbyist?
> If so, names/brands?
Engine black.
You can get a similar product for motorcycle exhaust header pipes, but I
think it has to be cured at high temperature to make it set properly
(blowtorch).
Ecnerwal
Roberto Waltman <use...@rwaltman.com> wrote:
> A post in the TrimSlice forum [a] regarding the operating temperature
> of the device mentions that the "really nice nickel plated case" has
> an emissivity of about .03, while black epoxy paint has an emissivity
> of 0.89 with the expected benefits on cooling. [b]
>
> Is there a paint specifically designed to improve heat dissipation
> that is available in small quantities to the electronics homebuilder /
> hobbyist?
> If so, names/brands?
Well, for aluminum, you anodize it black. Small scale kits are available
There's probably a way to get nickel to turn black (chemically.) I don't
know it off the top of my head, but ISTR "black nickel" plating, so it's
likely not too hard to find.
With steel, heat and oil will get you there (black oxide finish). Or you
can try stopping at one of the pretty colors before black.
The advantage of these treatments over paint is that they don't add an
insulating layer (paint) to the metal to change its color. Still, for
starting with a shiny mirror surface, you can easily get better results
from turning it black with paint than from leaving it be - you just
might be able to do better by turning it black without paint.
Rustoleum Barbeque Black is a classic. Flat is better than glossy, but
for some things glossy may look better and be good enough. Baking it
helps it cure better.
--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.
Grant Edwards
> Grant Edwards wrote:
>>Is radiative cooling from a case even significant compared to
>>conducted/convenctive cooling?
>
> Good question, found the following:
> http://www.electronics-cooling.com/2001/02/dont-underestimate-radiation-in-electronic-cooling/
> www.engineering.uiowa.edu/~becker/documents.dir/JEP1991.pdf
Both of these appear to address cooling of components on a circuit
board, not the cooling of the case. I wouldn't think the two cases
would be analogous. The heat transfer from compoents on a board is
typically generated in small, localized spots with pretty large
temperature differences between the heat source and environment.
Heat trasferred from a case is usually over a very large, uniform area
that's only a few degrees warmer than the environment.
>>Isn't a layer of epoxy paint on an aluminum case going to
>>significantly increase the thermal resistance?
> Ditto. Increase, yes. By how much? Relevant or not?
Good question.
--
Grant Edwards grant.b.edwards Yow! Gee, I feel kind of
at LIGHT in the head now,
gmail.com knowing I can't make my
satellite dish PAYMENTS!
John Larkin
<inv...@invalid.invalid> wrote:
>On 2011-08-23, Tim Wescott <t...@seemywebsite.com> wrote:
>> On Tue, 23 Aug 2011 12:10:38 -0400, Roberto Waltman wrote:
>>
>>> A post in the TrimSlice forum [a] regarding the operating temperature of
>>> the device mentions that the "really nice nickel plated case" has an
>>> emissivity of about .03, while black epoxy paint has an emissivity of
>>> 0.89 with the expected benefits on cooling. [b]
>>>
>>> Is there a paint specifically designed to improve heat dissipation that
>>> is available in small quantities to the electronics homebuilder /
>>> hobbyist?
>>> If so, names/brands?
>>>
>>> Thanks,
>>>
>>> [a] http://www.trimslice.com/forum/
>>> [b]
>>> http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
>>
>> Not that I know of. But if it looks flat black, chances are it's got
>> good emissivity. Or, to rephrase that: if it's got good even emissivity
>> in visible light, chances are it has good even emissivity across the
>> spectrum.
>
>Is radiative cooling from a case even significant compared to
>conducted/convenctive cooling?
Depends of the surface temperature. At moderate temps, like won't burn
your hand, radiation is a minor factor.
>
>Isn't a layer of epoxy paint on an aluminum case going to
>significantly increase the thermal resistance?
Not much. The first tenth of an inch of air on each side will have a
much higher thermal resistance than the thin layer of paint.
John
Andrew Smallshaw
>
> Is radiative cooling from a case even significant compared to
> conducted/convenctive cooling?
>
> Isn't a layer of epoxy paint on an aluminum case going to
> significantly increase the thermal resistance?
If that's a concern then for metal cases one of the commercial
blacking products is probably the way to go since the resulting
layer is only a few microns thick. I have vague memories of "Carr's
Metal Back": good model shops (particularly ones with a railway
emphasis) should have it.
--
Andrew Smallshaw
and...@sdf.lonestar.org
Martin Brown
> On 2011-08-23, Roberto Waltman<use...@rwaltman.com> wrote:
>> Grant Edwards wrote:
>>> Is radiative cooling from a case even significant compared to
>>> conducted/convenctive cooling?
>>
>> Good question, found the following:
>> http://www.electronics-cooling.com/2001/02/dont-underestimate-radiation-in-electronic-cooling/
>> www.engineering.uiowa.edu/~becker/documents.dir/JEP1991.pdf
>
> Both of these appear to address cooling of components on a circuit
> board, not the cooling of the case. I wouldn't think the two cases
> would be analogous. The heat transfer from compoents on a board is
> typically generated in small, localized spots with pretty large
> temperature differences between the heat source and environment.
>
> Heat trasferred from a case is usually over a very large, uniform area
> that's only a few degrees warmer than the environment.
My recollection is that as a rule of thumb at normal ambient
temperatures passive radiative cooling becomes important at about 50C
and above and grows as T^4. I was surprised how painting a classic old
style linear regulator PSU box (of shiny folded aluminium) dirty black
immediately resolved a thermal problem once long ago.
>
>>> Isn't a layer of epoxy paint on an aluminum case going to
>>> significantly increase the thermal resistance?
>
>> Ditto. Increase, yes. By how much? Relevant or not?
>
> Good question.
What matters is whether the paint appears "black" in the long wave
thermal infrared. It does seem a shame to spoil the nice case - does it
really run hot enough to justify molesting its appearance?
Regards,
Martin Brown
Roberto Waltman
>What matters is whether the paint appears "black" in the long wave
>thermal infrared.
While searching on this subject found a page claiming that any paint
based on organic pigments has a high emissivity ( > 0.8 ) in the
infrared, regardless of the visible color.
> It does seem a shame to spoil the nice case - does it
> really run hot enough to justify molesting its appearance?
I was asking in general - If you are referring to the TrimSlice, some
owners posts suggest it runs too hot. The manufacturer's response is
(a) it is within limits and (b) they are still working the bugs out of
the Linux power management.
And no, I would not "molest its appearance", only because it will
probably void the warranty. Now, after the it expires...
Jan Panteltje
<use...@rwaltman.com> wrote in <3mt757lophsg8b0si...@4ax.com>:
Sometimes this sort of problems can be solved by pointing a small fan on the case.
I use a small 12 V PC processor fan to cool the external heatsink of my CB transmitter.
Ian Field
"Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in message
news:SES4q.3279$GG2....@newsfe01.iad...
> On 23/08/2011 19:29, Grant Edwards wrote:
>> On 2011-08-23, Roberto Waltman<use...@rwaltman.com> wrote:
>>> Grant Edwards wrote:
>>>> Is radiative cooling from a case even significant compared to
>>>> conducted/convenctive cooling?
>>>
>>> Good question, found the following:
>>> http://www.electronics-cooling.com/2001/02/dont-underestimate-radiation-in-electronic-cooling/
>>> www.engineering.uiowa.edu/~becker/documents.dir/JEP1991.pdf
>>
>> Both of these appear to address cooling of components on a circuit
>> board, not the cooling of the case. I wouldn't think the two cases
>> would be analogous. The heat transfer from compoents on a board is
>> typically generated in small, localized spots with pretty large
>> temperature differences between the heat source and environment.
>>
>> Heat trasferred from a case is usually over a very large, uniform area
>> that's only a few degrees warmer than the environment.
>
> My recollection is that as a rule of thumb at normal ambient temperatures
> passive radiative cooling becomes important at about 50C and above and
> grows as T^4. I was surprised how painting a classic old style linear
> regulator PSU box (of shiny folded aluminium) dirty black immediately
> resolved a thermal problem once long ago.
On occasion I've had good results with thick black marker pen and it sticks
to aluminium better than most paints.
Roberto Waltman
>Well, for aluminum, you anodize it black. Small scale kits are available
Yes, but... From the materials emissivity table mentioned in the first
post, there are better options, even if not so pretty:
Aluminum Anodized 0.77 (doesn't mention color)
Black Enamel Paint 0.80
Black Epoxy Paint 0.89
Black Silicone Paint 0.93
Black Parson Optical 0.95
And from http://snap.fnal.gov/crshield/crs-mech/emissivity-eoi.html
Chemglaze Black Paint Z3O6 0.91
3M Black Velvet Paint 0.91
Martin Black Paint N-15O-1 0.94
Martin Black Velvet Paint 0.94
Glen Walpert
Probably not, especially if thin. According to an engineer at a radiator
company I called with concerns about some painted aluminum radiators,
there is no detectable increase in thermal resistance if the paint is
less than about .002 inches thick, at least in forced air flow radiators.
If you go through the calculations I think you will find that the paint
thermal resistance is small compared to the air "film resistance", the
thermal resistance of the thin layer of air which is semi-stuck to a
solid surface, not taking much part in convection flow. This should be
covered in any heat transfer book.
John Larkin
Black whiteboard pens have an emissivity close to 1. That's cool,
because you can dab a part, thermally image it, and then wipe it
clean.
The OP could paint the box black with one of those and see if the
temperature changes much, thermocouple somewhere inside maybe.
John
Roberto Waltman
>Black whiteboard pens have an emissivity close to 1. That's cool,
>because you can dab a part, thermally image it, and then wipe it
>clean.
>
>The OP could paint the box black with one of those and see if the
>temperature changes much, thermocouple somewhere inside maybe.
[ Putting on my OP hat ] I ordered a TrimSlice but have not received
it yet, so I don't know first-hand if heating is really a problem.
My question (triggered by some TrimSlice forum posts) was of a more
general nature. Wanted to know, for now and for future reference, to
which extent heating problems could be addressed using paint or
coatings. (Answer: more than what I expected.)
I was surprised to find paint/coatings for roofs, for example,
specifically mentioning heat issues, but nothing for electronic
systems.
Thanks for all the replies,
Ian Field
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
news:qm2857p760ffmlsnd...@4ax.com...
Years ago I had a contract to convert a motley assortment of VGA mono
monitors for Atari use, one particular make was especially prone to
overheating, either the line transistor, B+ rectifier or the PSU in general
would blow.
In the short term I kept things under control by blacking the heatsinks with
black marker pen - that bought me time to think of replacing the bipolar
line driver with a MOSFET.
No other modifications were needed once that fix was established.
lang...@fonz.dk
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 23 Aug 2011 20:32:10 +0100, "Ian Field"
>
>
>
>
>
>
>
>
>
>
> >"Martin Brown" <|||newspam...@nezumi.demon.co.uk> wrote in message
> >news:SES4q.3279$GG2....@newsfe01.iad...
> >> On 23/08/2011 19:29, Grant Edwards wrote:
> >>> On 2011-08-23, Roberto Waltman<use...@rwaltman.com> wrote:
> >>>> Grant Edwards wrote:
> >>>>> Is radiative cooling from a case even significant compared to
> >>>>> conducted/convenctive cooling?
>
> >>>> Good question, found the following:
> >>>>www.engineering.uiowa.edu/~becker/documents.dir/JEP1991.pdf
>
> >>> Both of these appear to address cooling of components on a circuit
> >>> board, not the cooling of the case. I wouldn't think the two cases
> >>> would be analogous. The heat transfer from compoents on a board is
> >>> typically generated in small, localized spots with pretty large
> >>> temperature differences between the heat source and environment.
>
> >>> Heat trasferred from a case is usually over a very large, uniform area
> >>> that's only a few degrees warmer than the environment.
>
> >> My recollection is that as a rule of thumb at normal ambient temperatures
> >> passive radiative cooling becomes important at about 50C and above and
> >> grows as T^4. I was surprised how painting a classic old style linear
> >> regulator PSU box (of shiny folded aluminium) dirty black immediately
> >> resolved a thermal problem once long ago.
>
> >On occasion I've had good results with thick black marker pen and it sticks
> >to aluminium better than most paints.
>
> Black whiteboard pens have an emissivity close to 1. That's cool,
> because you can dab a part, thermally image it, and then wipe it
> clean.
>
> The OP could paint the box black with one of those and see if the
> temperature changes much, thermocouple somewhere inside maybe.
>
> John
I wonder if something like clear Polyurethane would make a difference?
-Lasse
lang...@fonz.dk
> On a sunny day (Tue, 23 Aug 2011 15:02:53 -0400) it happened Roberto Waltman
>
>
>
>
>
>
>
>
>
> >Martin Brown wrote:
>
> >>What matters is whether the paint appears "black" in the long wave
> >>thermal infrared.
>
> >While searching on this subject found a page claiming that any paint
> >based on organic pigments has a high emissivity ( > 0.8 ) in the
> >infrared, regardless of the visible color.
>
> >> It does seem a shame to spoil the nice case - does it
> >> really run hot enough to justify molesting its appearance?
>
> >I was asking in general - If you are referring to the TrimSlice, some
> >owners posts suggest it runs too hot. The manufacturer's response is
> >(a) it is within limits and (b) they are still working the bugs out of
> >the Linux power management.
>
> >And no, I would not "molest its appearance", only because it will
> >probably void the warranty. Now, after the it expires...
> >--
> >Roberto Waltman
>
> Sometimes this sort of problems can be solved by pointing a small fan on the case.
> I use a small 12 V PC processor fan to cool the external heatsink of my CB transmitter.
it kinda negates the point of a sleek slim computer if you have to put
a processor fan
next to it to use it ;)
-Lasse
John Larkin
Most organics are pretty opaque (high e) at thermal wavelengths, but I
don't know about that one. Black plastic garbage bags are almost
transparent!
John
George Herold
> Martin Brown wrote:
> >What matters is whether the paint appears "black" in the long wave
> >thermal infrared.
>
> While searching on this subject found a page claiming that any paint
> based on organic pigments has a high emissivity ( > 0.8 ) in the
> infrared, regardless of the visible color.
That's interesting. I was buying 'black' cloth to block near IR light
~800nm.
Black 'plastic'* cloth was no good, where natural canvas worked
great.
George H.
*think velour or plush velvet
Jon Kirwan
<ghe...@teachspin.com> wrote:
>On Aug 23, 3:02 pm, Roberto Waltman <use...@rwaltman.com> wrote:
>> Martin Brown wrote:
>> >What matters is whether the paint appears "black" in the long wave
>> >thermal infrared.
>>
>> While searching on this subject found a page claiming that any paint
>> based on organic pigments has a high emissivity ( > 0.8 ) in the
>> infrared, regardless of the visible color.
>
>That's interesting. I was buying 'black' cloth to block near IR light
>~800nm.
>Black 'plastic'* cloth was no good, where natural canvas worked
>great.
>
>George H.
>
>*think velour or plush velvet
><snip>
Hi, George. I am looking at quickly pulling together a
papertape reader. Something that will transmit to a virtual
COM port via USB. Already have most of it done, due to a
different project I completed a month ago or more -- this
would simply be a 'front end.'
Anyway, I ordered up some standard LTR-4206 (not the E part
with the dark blocking plastic) phototransistors from jameco
because they had them 'dirt cheap' (0.75 cents each.)
(I am still going to play around with using simple LEDs as
detectors, but I didn't have any phototransistors other than
two very old ones.)
Anyway, I was curious about the paper in the paper tape. So
I looked up transmission by wavelength for paper. (If you
know of a good published paper on paper transmission and in
particular the paper used in 1970's style paper tape, by all
means tell me!!) I found that in the visible it's fairly
opaque. But in the IR transmission rises and diffusion
declines. So it gets a little more problematic for me, I
think.
High emissivity is associated with high absorption (for
obvious reasons.) Roberto's comment about finding some
comments about high emissivity in the IR for organic pigments
makes me wonder, as being as ignorant as I am right now about
these things I'd tend to think that what I found recently
about paper (which _is_ organic) flies just a little bit in
the face of having higher emissivity in the IR.
But it's probably just my ignorance and these two facts are
not in contradiction.
Anyway, I expect to find out soon. The LTR-4206's have been
shipped out this morning and I may see them this week. That
plus some testing with various LEDs as detectors in a micro
setup will tell me what I'd like to do in terms of finishing
this project. (Found a cache of old paper tapes from "back
when" and I'd like to transmit them into the computer as
archives.) Just in case you are interested, I plan to test
out this idea regarding using the LEDs as detectors:
http://www.merl.com/papers/docs/TR2003-35.pdf
Also suggests some interesting thoughts on low speed, bi
directional, lost cost (zero, essentially) transmission using
a simple LED. Looks like fun to do.
Jon
1 Lucky Texan
you need an audio file to play that goes 'ka-chunk,ka-chunk,ka-
chunk,ka-chunk,ka-chunk'
we sometimes would 'butterfly' tapes instead of rolling them. make a
figure eight between thumb and pinky - like an infinity symbol.
good times.....good times
Jon Kirwan
I had wired up my own "back in the day." I couldn't afford
anything like a punch... probably would still blanche at the
cost today. And at the time, I couldn't afford a reader,
either. So i built a hand-pulled one using 9 detectors and
an optical source and pulled the tapes through by hand. I
still plan on doing something quite similar, except now I can
use a microcontroller and some techniques that weren't
available to me, back then.
There really wasn't much sound from hand-pulling. So I can
live without the sound effects.
By the way, can still read an ASCII tape fluently by eye.
>we sometimes would 'butterfly' tapes instead of rolling them. make a
>figure eight between thumb and pinky - like an infinity symbol.
Yes, I remember. I didn't like the folded situation, though.
I used, and still have, those clear cylindrical tape
containers with the simple lids.
I think I might have a tyvek tape or two. I see that the
stuff is still available (as is paper tape) but costs 10X the
paper, about as it did back then.
>good times.....good times
Yes. Damn, if only I could have latched onto and kept an
ASR-33 or even a KSR-35, and functioning. Current loop,
4-20mA, but I can convert that easily today.
Jon
Martin Brown
> Martin Brown wrote:
>
>> What matters is whether the paint appears "black" in the long wave
>> thermal infrared.
>
> While searching on this subject found a page claiming that any paint
> based on organic pigments has a high emissivity (> 0.8 ) in the
> infrared, regardless of the visible color.
That is correct you need to know how the paint behaves for thermal IR.
Some of the better research on this in the open literature is for
observatory domes which in the old days were as white as possible to
minimise daytime heat load but now are mixed with other components.
Their problem was at night the dome surface would supercool because of
radiative losses to the sky and cold air would pour into the dome
through the slit producing local turbulence - which is always bad.
There is a lot of research for novel pigments in fire protection paints
at the moment that reflect thermal IR and slow the ignition of painted
wood (other flammable materials).
Your ideal would like the astronomers of old be a perfect white paint in
the visible and near IR that is black for thermal IR around 10um.
>
>> It does seem a shame to spoil the nice case - does it
>> really run hot enough to justify molesting its appearance?
>
> I was asking in general - If you are referring to the TrimSlice, some
> owners posts suggest it runs too hot. The manufacturer's response is
> (a) it is within limits and (b) they are still working the bugs out of
> the Linux power management.
>
> And no, I would not "molest its appearance", only because it will
> probably void the warranty. Now, after the it expires...
One thought is that you might be able to get away with something as
simple as black dry marker pen over the hotspots (assuming they are 50C
or more which is when radiative losses become really important).
Test it on some bit that won't matter first. Some anodised type finishes
can end up permanently disfigured by pens that will wipe off a
whiteboard - don't ask how I know this ;-).
Regards,
Martin Brown
Jan Panteltje
"lang...@fonz.dk" <lang...@fonz.dk> wrote in
<5ec51357-c61d-4aa4...@l7g2000vbz.googlegroups.com>:
>> Sometimes this sort of problems can be solved by pointing a small fan on =
>the case.
>> I use a small 12 V PC processor fan to cool the external heatsink of my C=
>B transmitter.
>
>it kinda negates the point of a sleek slim computer if you have to put
>a processor fan
>next to it to use it ;)
>
>-Lasse
Dunno, I have a fan on my Nvidia graphics card that adds maybe 1 cm to the height.
Just a bit of airflow along the outside of a cabinet makes ALL the difference.
And it would keep the look from the front intact.
George Herold
Hi Jon,
"But it's probably just my ignorance and these two facts are
not in contradiction."
Well we are equally ignorant then. I have no idea why black canvas
was better at blocking NIR (N=near), than manmade materials.
I guess the lesson to learn is never assume that behavior in the
visible extends to other wavelengths.
Many moons ago we used sheets of white paper as attenuators for a FIR
(F=far, lambda > 10 um) laser. Each sheet blocked something like
20-30% of the light.
(but don't quote me on that number.) So I can at least confirm the
white paper transmission at long wavelengths.
BTW 3M black electrical tape is great at blocking light out to at
least ~1 um. (A piece over a silicon photodiode blocks almost
everything.)
George H.
Ecnerwal
Jon Kirwan <jo...@infinitefactors.org> wrote:
> Yes. Damn, if only I could have latched onto and kept an
> ASR-33 or even a KSR-35, and functioning. Current loop,
> 4-20mA, but I can convert that easily today.
>
> Jon
Keep an eye on sleazebay. Not too much there at the moment but it does
tend to be the default place old junque shows up (sometimes desperately
overpriced, but you learn to let those slide, or grit your teeth and
pay, in which case it may not have been all that overpriced after
all...) I guess there is something described as a model 33 teletype
(searching on teletype rather than paper tape), but it looks like only
the middle part of what you want.
On the other had, paper tape reader units off old cnc machine tools are
more common there.
Also several standalone PTR units of various types (GE, Barudan, K&T)
Spehro Pefhany
<MyName...@ReplaceWithMyVices.Com.invalid> wrote:
>In article <cdv857t804tek68vp...@4ax.com>,
> Jon Kirwan <jo...@infinitefactors.org> wrote:
>
>> Yes. Damn, if only I could have latched onto and kept an
>> ASR-33 or even a KSR-35, and functioning. Current loop,
>> 4-20mA, but I can convert that easily today.
>>
>> Jon
>
>Keep an eye on sleazebay. Not too much there at the moment but it does
>tend to be the default place old junque shows up (sometimes desperately
>overpriced, but you learn to let those slide, or grit your teeth and
>pay, in which case it may not have been all that overpriced after
>all...) I guess there is something described as a model 33 teletype
>(searching on teletype rather than paper tape), but it looks like only
>the middle part of what you want.
>
>On the other had, paper tape reader units off old cnc machine tools are
>more common there.
>
>Also several standalone PTR units of various types (GE, Barudan, K&T)
Shipping an ASR-33 will kill you. I remember how hard it was getting
mine into the dumpster..
Michael A. Terrell
Spehro Pefhany wrote:
>
> Shipping an ASR-33 will kill you. I remember how hard it was getting
> mine into the dumpster..
It helps to unplug it, first. ;-)
--
You can't have a sense of humor, if you have no sense.
Jon Elson
>
> A post in the TrimSlice forum [a] regarding the operating temperature
> of the device mentions that the "really nice nickel plated case" has
> an emissivity of about .03, while black epoxy paint has an emissivity
> of 0.89 with the expected benefits on cooling. [b]
>
> Is there a paint specifically designed to improve heat dissipation
> that is available in small quantities to the electronics homebuilder /
> hobbyist?
> If so, names/brands?
>
Equipment that runs reasonably near room temperature exchanges nearly
all the heat by conduction/convection, not radiation. Now, if you are
talking about major heating elements, then radiation does enter the
picture. But, for electronic enclosures where you can put your hand on
the box, coatings for the most part make no difference at all. Stirring
the air inside the box so the internally-generated heat warms the entire
box's inside can be a big help.
Jon
Jon Kirwan
Yeah, but I like feeling that I grasp theory, too. When I
get information that questions my grasp, .... Anyway, no
matter what.... test, test, test.
>Many moons ago we used sheets of white paper as attenuators for a FIR
>(F=far, lambda > 10 um) laser. Each sheet blocked something like
>20-30% of the light.
>(but don't quote me on that number.) So I can at least confirm the
>white paper transmission at long wavelengths.
Yeah, I was looking at curves that went into the NIR, only.
Maybe a micron? It was mostly dealing with visible, because
that's what they were discussing for the most part. They
just happened to show a tail in the NIR. It had gone from
strong blocking in the blue to perhaps 40% transmission at 1
micron.
But paper is so different, too. Fiber thicknesses, density,
layers, and so on. I think I read it is usually at least 10
fiber layers deep. Anyway, papertape is a little different
in appearance than stock paper and may have significant
differences. I'm going to have to test at various
wavelengths.
Interesting thing is that at 0.1" between holes, I can't use
anything like the 5mm or 3mm bodies of typical LEDs and photo
transistors designed for throughhole. Unless I grind the
daylights out of them to reduce thicknesses. I'm considering
other ideas, since I also don't want cross-talk from pressing
closely a bunch of plastic bodies with ground surfaces.
Standard vectorboard with plated throughholes looks like an
option, but I'd probably need fiber optic wire of the right
diameter (haven't measured that, though I could always order
what I want, I suppose) to fit those holes. That would allow
me to basically place the detectors anywhere. (Could also
drill an aluminum block for same purpose.) I'd use a bright
source above and to mount the fibers on the LED bodies I'd
hold by hand and observe where the light targets and then
glue them down to the LED/photobjt body and hold until dry?
This optical head is not entirely going to be easy, if I
don't use SMT. The SMT path is nice. LEDs are tiny and can
actually be spaced at 0.1" even when used long-wise, let
alone along the thin width. But then I have to go get those
-- I have zero SMT LEDs in my collection. Plus make a board
with spots for nine of them.
And I still have to work out what is going to do well with
this paper, wavelength wise and detector wise. The rest is
all going to be a piece of cake.
>BTW 3M black electrical tape is great at blocking light out to at
>least ~1 um. (A piece over a silicon photodiode blocks almost
>everything.)
Hmm. I may think about that as a barrier between detectors
if I don't go the SMT route.
Jon
gregz
> On 2011-08-23, Tim Wescott <t...@seemywebsite.com> wrote:
>> On Tue, 23 Aug 2011 12:10:38 -0400, Roberto Waltman wrote:
>>
>>> A post in the TrimSlice forum [a] regarding the operating temperature of
>>> the device mentions that the "really nice nickel plated case" has an
>>> emissivity of about .03, while black epoxy paint has an emissivity of
>>> 0.89 with the expected benefits on cooling. [b]
>>>
>>> Is there a paint specifically designed to improve heat dissipation that
>>> is available in small quantities to the electronics homebuilder /
>>> hobbyist?
>>> If so, names/brands?
>>>
>>>
>>> [a] http://www.trimslice.com/forum/
>>> [b]
>>> http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
>>
>> Not that I know of. But if it looks flat black, chances are it's got
>> good emissivity. Or, to rephrase that: if it's got good even emissivity
>> in visible light, chances are it has good even emissivity across the
>> spectrum.
>
> conducted/convenctive cooling?
>
> significantly increase the thermal resistance?
I think it could improve it. Just sandblasting a shiny surface might be
better.
Greg
Ecnerwal
Jon Kirwan <jo...@infinitefactors.org> wrote:
> But paper is so different, too. Fiber thicknesses, density,
> layers, and so on. I think I read it is usually at least 10
> fiber layers deep. Anyway, papertape is a little different
> in appearance than stock paper and may have significant
> differences. I'm going to have to test at various
> wavelengths.
Well, I noticed that the description of the punches mentioned that the
tape was "oiled paper", which would affect light transmission quite a
bit. Before glass was cheap, oiled paper (among other things) was used
for windows by the less wealthy, since it transmitted more visible light
than plain paper (shedding water was likely also good...) Presumably
tape is oiled to keep the punches happy and/or cut down on dust.
1 Lucky Texan
> On Wed, 24 Aug 2011 05:47:32 -0700 (PDT), George Herold
>
>
>
>
>
>
>
>
>
If you alternated some small front-surface, 45degree mirrors, you can
double the 'pitch'/spacing required for the detectors. 2 staggered
rows if you get the idea.
Robert Wessel
It sounds like you may be rather further along on this, but if I were
tasked with reading paper tape today, particularly a one-off
application, I think my first inclination would be to use a camera of
decent resolution, and pull the tape past that at a relatively
constant rate. Add a little lighting, a contrasting background so the
camera can see the holes, and then processes the data stream out of
the video.
Actually that would be my second inclination - a friend of mine
actually has a couple of ASR-33s in his basement (and one of them was
actually hauled out and operated, four or five years ago). And I
probably have an RS-232/current loop converter somewhere in the parts
bin.
Jon Kirwan
<1luck...@gmail.com> wrote:
><snip>
>If you alternated some small front-surface, 45degree mirrors, you can
>double the 'pitch'/spacing required for the detectors. 2 staggered
>rows if you get the idea.
Yeah. I think I have an easier method, right now. I've used
a metal washer (convenient only, not because it is a washer)
that is about 2" diameter and wide. I used a piece of vector
board for my 0.1" spacings and drilled through each of 9
holes, but two rows for a total of 18 holes. I then milled
out the span between adjacent holes making 9 slots. I then
ground the sides of 9 3mm LTR-4206 phototransistors so that
they would neatly fit in. These will be glued (haven't done
that yet) into the holes and let dry. Once that is over, I
use a dremel and a grind stone to flaten the tops down to the
surface. Then I cut the metal rectangle out of the washer,
polish and nicen up the edges and mount it into a similarly
sized depression I cut into a block of hardwood. Large flat
surface, over which I mount a polished bit of clear plastic
over the area to keep the papertape near the detector tops.
Then the electronic testing begins and I figure out and test
a reasonable circuit.
And I hope I don't run into problems dicerning when a hole is
present.
Turns out a friend of mine still has his Remex reader. 120cps
full speed, but allows 'step mode.' I might adapt that one,
too, for USB. (It hooks up to a 68020 PIO chip of some kind,
right now, and was used with an Altair 8800 system and is
pretty dusty right now.)
This is kind of fun. Too bad I don't have proper tools. But
I'm getting by okay.
Jon
Jon Kirwan
I am looking around for an ASR-33. :) Tell your friend if
he's not going to make that stuff useful, to consider the
idea of parting with it so someone else can.
I don't like the camera idea... It's not necessarily a
one-off (I do have friends who are interested in the
results.) I don't want to have to use a controlled pull
rate. And I'm doing this in part as a project to teach my
son more about design and construction as well as software.
Just taking a bunch of photos that are stitched together in
some fashion and then analyzed will take more development
time, anyway. This is going very fast, already. I just
started about an hour ago dilling holes in a washer and
grinding the detectors. The read head will be complete in
less than 3 hours' time, at this rate. I already have almost
all the software done from a different project that accepts
parallel port data and strobe and sends it into the USB port
that I started and finished quite quickly, more than a month
back. With the sprocket hole being the strobe, it's almost a
dead match for this, given a little bit of signal
conditioning on the read head. And I can handle thousands of
characters per second on the other device, already -- way
more than I can ever need here. I like leveraging other work
-- it also teaches lessons.
Jon
Frnak McKenney
> On Wed, 24 Aug 2011 23:48:57 -0500, Robert Wessel
><robert...@yahoo.com> wrote:
>
>>On Wed, 24 Aug 2011 15:11:39 -0700, Jon Kirwan
>><jo...@infinitefactors.org> wrote:
>>
>>>On Wed, 24 Aug 2011 05:47:32 -0700 (PDT), George Herold
>>><ghe...@teachspin.com> wrote:
>>>
>>>>On Aug 23, 11:26 pm, Jon Kirwan <j...@infinitefactors.org> wrote:
>>>>> On Tue, 23 Aug 2011 17:43:51 -0700 (PDT), George Herold
>>>>> <gher...@teachspin.com> wrote:
>>>>> Hi, George. I am looking at quickly pulling together a
>>>>> papertape reader. Something that will transmit to a virtual
>>>>> COM port via USB. Already have most of it done, due to a
>>>>> different project I completed a month ago or more -- this
>>>>> would simply be a 'front end.'
[...]
>>>This optical head is not entirely going to be easy, if I
>>>don't use SMT. The SMT path is nice. LEDs are tiny and can
>>>actually be spaced at 0.1" even when used long-wise, let
>>>alone along the thin width. But then I have to go get those
>>>-- I have zero SMT LEDs in my collection. Plus make a board
>>>with spots for nine of them.
[...]
> ... This is going very fast, already. I just
> started about an hour ago dilling holes in a washer and
> grinding the detectors. The read head will be complete in
> less than 3 hours' time, at this rate. I already have almost
> all the software done from a different project that accepts
> parallel port data and strobe and sends it into the USB port
> that I started and finished quite quickly, more than a month
> back. With the sprocket hole being the strobe, it's almost a
> dead match for this, given a little bit of signal
> conditioning on the read head. And I can handle thousands of
> characters per second on the other device, already -- way
> more than I can ever need here. I like leveraging other work
> -- it also teaches lessons.
Jon,
I'm jumping into this conversation a bit late, and it sounds like
you already have a workable solution for Reader #1. However, if
you decide you don't want to do all that drilling and grinding and
sanding and lens-polishing for Reader #2, you might consider letting
a manufacturer do some of the grunt work for you with a device like
this one:
Linear Sensor Array : TSL1401CS-LF
<http://www.taosinc.com/productdetails.aspx?ID=2>
Overview:
The TSL1401CS-LF (lead free) linear sensor array consists of a
128x1 array of photodiodes, associated charge amplifier circuitry,
and a pixel data-hold function that provides
simultaneous-integration start and stop times for all pixels. The
pixels measure 63.5 um (H) by 55.5 um (W) with 63.5-um
center-to-center spacing and 8-um spacing between pixels.
Operation is simplified by internal control logic that requires
only a serial-input (SI) signal and a clock.
Diodes, already laid out for you "like pretty maids all in a row"
(but hopefully less contrary than the gardener <grin!>). Requires
3.3-5V and "less than 5mA".
You can get it mounted on a board with a lens from Parallax for $50:
TSL1401 Linescan Imaging Sensor Daughterboard
<http://www.parallax.com/Store/Sensors/ColorLight/tabid/175/CategoryID/50/List/0/SortField/0/Level/a/ProductID/566/Default.aspx>
And there are others out there. Scavenging one from a $5-10 thrift
store scanner is another approach, but unless what you dig out is
clearly markes and an item with an available datasheet you may be in
for a lot of work.
But don't let any of this spoil the fun you're having building
Reader #1. It's a good lesson on the difference between creating
the first, proof-of-concept prototype (I seem to build a lot of
these! <grin!>) and building a production prototype.
Hope this helps...
Frank McKenney
--
"The true rule, in determining to embrace or reject any thing, is
not whether it has any evil in it; but whether it has more of
evil than of good. There are few things wholly evil or wholly
good. Almost every thing ... is an inseparable compound of the
two; so that our best judgment of the preponderance between them
is continually demanded." -- Abraham Lincoln
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney aatt mindspring ddoott com
dca...@krl.org
> Rustoleum Barbeque Black is a classic. Flat is better than glossy, but
> for some things glossy may look better and be good enough. Baking it
> helps it cure better.
>
My understanding is that glossy is better than flat. Flat generally
being glossy with talcum powder added.
Dan
StickThatInYourPipeAndSmokeIt
Silly man. flat black paint, especially for use in hot applications,
uses CARBON.
Rich Grise
reflectance works in both directions, ergo flat is better. In my not so
humble opinion. ;-)
But if I was using the enclosure itself to dissipate heat, I'd use a
finned heatsink, black anodized.
Cheers!
Rich
josephkk
<MyName...@ReplaceWithMyVices.Com.invalid> wrote:
>In article <rqsa57d69edlduim1...@4ax.com>,
> Jon Kirwan <jo...@infinitefactors.org> wrote:
>
>> But paper is so different, too. Fiber thicknesses, density,
>> layers, and so on. I think I read it is usually at least 10
>> fiber layers deep. Anyway, papertape is a little different
>> in appearance than stock paper and may have significant
>> differences. I'm going to have to test at various
>> wavelengths.
>
>Well, I noticed that the description of the punches mentioned that the
>tape was "oiled paper", which would affect light transmission quite a
>bit. Before glass was cheap, oiled paper (among other things) was used
>for windows by the less wealthy, since it transmitted more visible light
>than plain paper (shedding water was likely also good...) Presumably
>tape is oiled to keep the punches happy and/or cut down on dust.
All valid ideas. The oiled paper for punches was about 0.01% oil for
lubrication, more than that caused problems also. Oiled paper for windows
was almost 2% oil, with much more impact on transmissivity. For comparison
check wax paper for kitchen use in the grocery store.
For even greater fun some papers had plastic layers or even metallized
plastic layers. And some tapes were flat out metallized plastic (often
mylar).
I worked with/on ASR-33 type equipment in the early 1970s.
?-)
josephkk
wrote:
>On Wed, 24 Aug 2011 21:23:33 -0700 (PDT), 1 Lucky Texan
It sure sounds like a lot of fun.
Engineering is making what you want out of what you have.
?-)
Jon Kirwan
I just spent last night reading in my first papertape in a
long time. I'd forgotten the odor/smell of oiled paper tape.
But now all the memories flooding back. Of course, also the
winding and talking while winding with someone else nearby.
Interesting thing. While I've just been going through the
shed uncovering these old items, it turns out that the paper
tapes are still just fine. But that the old EPROMs have
actually lost their memories!! I suspect these tapes, even
modestly taken care of, will outsurvive many other forms of
recording data -- including writable DVD and CDROM.
Like papyrus, almost.
Well, I need to build up a linear light system -- long
filament followed optically by a glass or plastic rod
(cylinder lens) to reimage the filament onto the detectors as
a bright line.
This is a fair bit of fun, again. Went down to the store to
buy an aluminum cooking pan and some Coleman stove pots (also
aluminum) so that I had some soft metal to save my poor bits
from destruction in making the thing. Forgotten what it was
like to build up my own computer components, with the ease of
buying things in the huge market that now exists. Back then,
it was all by hook or by crook. And here, once again, it is
also. Love it.
Jon
Jon Kirwan
I just posted a little more elsewhere on this very point,
before reading what you just wrote. I'll add some details
here.
I started out using vector board as a drill guide. It's 0.1"
spacing, nicely. I was able to make tap points that way
exactly where I wanted them and very nicely aligned without
the need fo fancy equipment. Just a cordless drill and no
fixturing. Once I had that done, making the .06x.12 slots
wasn't difficult.
By the time I'd worked this out, it was late. I went down to
the store around 10PM, which meant not going to Home Depot or
the like. I wanted a specialized bit for milling out each
slot. A large store that included groceries but also some
tools and the like had a dremel bit that was just right. But
sadly, not carbide or strong -- specified only "soft metal."
Okay. So I decided to get it anyway, give up on the piece of
steel I was planning, and ran around looking for aluminum. In
the cooking section, got a nice rectangular baking pan
(without insulation compressed inside it) made entirely from
aluminum. Also, picked up some thinner stuff found in the
Coleman camp stove cooking stuff -- 25% sale, good luck. Took
all that home, night before last, and worked.
I do need to get a linear bulb with a filament of about the
right length. Incandescent. Then add, just below it and
also horizontal, a glass or plastic/acrylic cylinder rod to
refocus the filament onto the detector array. Like a ball
lens would do for a fiber optic system and a point source
like a diode, for example, but in 'array form' which means
dragging out the ball lens into a cylinder instead. That
should make a very nice, bright line exactly where I want it.
This whole thing is a lot of fun and reminds me of when I
didn't have _any_ money (few know what I mean as very few
people I knew then were anywhere near as poor -- so I mean it
here) to speak of and had only just gotten a job at $525/mo.
Had to build up everything, if I wanted it. I would
literally scrounge dumpsters at the phone company or
elsewhere for electronic parts. I'd dismantle TVs, you name
it.
I could buy all this stuff. Or I could use my friend's Remex
and just be done with the functional parts about getting
these tapes copied into a modern computer. But it wouldn't
be nearly as much fun and I can use his unit, anyway. So
it's more about recovering some of that fun -- and learning
experience as you go -- and teaching some kids who are
watching all this, right now.
I think some of this attitude has been lost, somehow. And it
is sooooo much fun and provides awareness and self-confidence
and pride, too.
I'll probably do up a finished hardwood surface and bury the
aluminum optical head so that the aluminum detector plate is
flush with the wood. There will be a top aluminum piece
placed with a gapping of about 0.02" above the detector plate
to keep the papertape closeby while it goes through and I
will use a thin sheet of aluminum along one side to both
create that 0.02" gapping as well as an 'edge' against which
the papertape gets properly aligned (I won't have sprocket
guides to start.) Will likely add some kind of washer-based
thing on both the incoming and departing sides to keep the
paper tape pressed against that guide.
Used to be able to buy these heads, I recall (not that I
could afford them, back then.) And now you can't even buy
them. But you can make them from scraps and from kitchen
supplies!!
This is fun.
Jon
josephkk
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 23 Aug 2011 15:18:40 -0700 (PDT), "lang...@fonz.dk"
><lang...@fonz.dk> wrote:
>
>>On 23 Aug., 22:21, John Larkin
>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>> On Tue, 23 Aug 2011 20:32:10 +0100, "Ian Field"
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> <gangprobing.al...@ntlworld.com> wrote:
>>>
<snip>
>>> The OP could paint the box black with one of those and see if the
>>> temperature changes much, thermocouple somewhere inside maybe.
>>>
>>> John
>>
>>I wonder if something like clear Polyurethane would make a difference?
>>
>>-Lasse
>
>Most organics are pretty opaque (high e) at thermal wavelengths, but I
>don't know about that one. Black plastic garbage bags are almost
>transparent!
>
>John
Could you post something like your visible and IR comparison pics that you
once did for kapton film/tape?
?-)
whit3rd
> On Thu, 25 Aug 2011 20:04:33 -0700 (PDT), "dca...@krl.org"
> <dca...@krl.org> wrote:
>
> >On Aug 23, 2:20 pm, Ecnerwal
> >
> >> Rustoleum Barbeque Black is a classic.
> >My understanding is that glossy is better than flat. Flat generally
> >being glossy with talcum powder added.
> Silly man. flat black paint, especially for use in hot applications,
> uses CARBON.
Carbon black isn't chemically stable at high temperatures; the
common pigment for heat-stable black paints is Fe3O4, magnetite.
It's also common in inks (your newspaper might use carbon black
ink, but the dollar bill black ink is magnetic, and so is most
laser printer toner).
1 Lucky Texan
> On Sat, 27 Aug 2011 19:12:18 -0700, josephkk
>
>
>
>
>
>
>
>
>
> >On Thu, 25 Aug 2011 01:22:57 -0700, Jon Kirwan <j...@infinitefactors.org>
Maybe you could use a cold-cathode backlight from a laptop? Fairly
bright and already a 'line source'. Or, cut a slit in some aluminum to
make an aperture/mask to place in front of a regular incandescent
bulb. Probably still need a condenser lens as you mention. A glass
stirring rod used in chemistry might work. Or if there is a
stainedglass hobbysupply around, ask them if they also have
'lampworking' supplies or know where you could get some clear glass
rod.
StickThatInYourPipeAndSmokeIt
wrote:
But the only IR black body surface paint I know of (it is patented)
that the NIST even approved of, is the IR paint made by Mikron Instrument
Company. I do not think they make it any more, but it specifically
mentions the use of carbon as part of their selling points on the page
for the material.
We used it on the black body calibration source "ovens" we sold, and the
NIST and anybody else with any brains uses our (I worked there
once)calibration sources.
Anyway, it was specifically made to emit evenly across a wide temp and
at as close to 1.0 as it gets (or can get).
John Larkin
This is fun:
http://www.youtube.com/watch?v=6mV4ecEbV1s
One other interesting thing: water, ice, and snow are black at thermal
wavelengths, e around 0.98.
John
John Larkin
wrote:
>On Thursday, August 25, 2011 11:09:24 PM UTC-7, StickThatInYourPipeAndSmokeIt wrote:
Of course. He's AlwaysWrong.
John
Hans-Bernhard Bröker
> actually lost their memories!! I suspect these tapes, even
> modestly taken care of, will outsurvive many other forms of
> recording data -- including writable DVD and CDROM.
Well, except maybe that the amount of paper needed to hold the content
of a single DVD could be heavy enough to _crumble_ under its own weight,
if doesn't crash right through the floor before that. The paper to
store a non-negligible DVD collection might just have enough mass to
collapse itself into a black hole ;-P
It's one of those "the internet still can't beat a 747 full of DVDs on
bandwidth" kinds of argument. Yes, well-made books can outlast a lot of
higher-density archive media --- but what good does that do you with
data being produced at a higher bandwidth than the trees can be grown to
make the paper to print them on?
> Well, I need to build up a linear light system -- long
> filament followed optically by a glass or plastic rod
> (cylinder lens) to reimage the filament onto the detectors as
> a bright line.
A "point" source parallelized by a spherical lense/mirror and then
focussed onto a line by a cylinder might be a whole lot easier ...
Hans-Bernhard Bröker
> One other interesting thing: water, ice, and snow are black at thermal
> wavelengths, e around 0.98.
Indeed. In our physics lectures they used raw arc lights to project
experiments onto a wall several meters away for hundreds of students to
see nice and big, and without having to dim the normal lights.
Now unfiltered arc-light is seriously bad news if your experiment is
heat-sensitive at all --- worse even than halogen light bulbs. So
whenever that was an issue, they just parked a glass box full of water
in the light's path, and that was that taken care of.
StickThatInYourPipeAndSmokeIt
You are always a peanut gallery comment producing dweeb. You wouldn't
know either way, and in this case in particular.
Good job, however, of showing us all once again just how pathetic you
are.
Most laser printer toner is NON-magnetic. It is an electrostatic
action that gives it its mobility, not magnetism. AND it cannot be
magnetic or folks could print forged checks with it.
It is not magnetic on US currency EITHER.
There are specific mixes of black ink meant for printing a specific area
on checks that IS magnetic (a security and computer reading feature).
Most if not all others are, for that reason alone, non-magnetic.
So you and he are clueless.
My Name Is Tzu How Do You Do
<HBBr...@t-online.de> wrote:
>On 28.08.2011 07:48, Jon Kirwan wrote:
>
>> actually lost their memories!! I suspect these tapes, even
>> modestly taken care of, will outsurvive many other forms of
>> recording data -- including writable DVD and CDROM.
>
>Well, except maybe that the amount of paper needed to hold the content
>of a single DVD could be heavy enough to _crumble_ under its own weight,
That would depend on how fine the printed "data" on the "pages" would
be, and how much of the page that print covered. Probably fit it all on
less that a ream of paper, done right. Zeros and ones can simply be
"dot" or "no dot".
>if doesn't crash right through the floor before that. The paper to
>store a non-negligible DVD collection might just have enough mass to
>collapse itself into a black hole ;-P
Must have been where your massive brain went.
>It's one of those "the internet still can't beat a 747 full of DVDs on
>bandwidth" kinds of argument.
Which is stupid because the Internet DELIVERS that much data from many
to many PCs. The 747 only carries a copy of any said data, and final
delivery onto even a small number of those PCs would make for a
bottleneck that would negate the claim.
But my gateways are the fastest in the world. 10GbE fiber all over the
place. Now I understand why the monthly rates are so high. This shtuff
ain't cheap. The cables alone add up to millions of dollars. We give
tens of millions of dollars a year in business to Cisco, Juniper, and
cable companies, and contract makers.
We probably spend $30M a year on HP computers alone.
Now, those systems move a LOT of data.
> Yes, well-made books can outlast a lot of
>higher-density archive media --- but what good does that do you with
>data being produced at a higher bandwidth than the trees can be grown to
>make the paper to print them on?
I used to watch every movie made in a year. There is just no way now,
with my regular job, and everything else to do. There are just too many
movies. So we BUY the movie in archive form, IF it got good reviews and
sells well, on a DVD or other medium. To watch at our leisure. No, DVDs
are NOT "burned". Only those you make at home are.
>> Well, I need to build up a linear light system -- long
>> filament followed optically by a glass or plastic rod
>> (cylinder lens) to reimage the filament onto the detectors as
>> a bright line.
>
>A "point" source parallelized by a spherical lense/mirror and then
>focussed onto a line by a cylinder might be a whole lot easier ...
"Optical cubes" can hold a TByte, but they are far more costly to make,
and hard drives are cheap and reliable. They are going to be around for
a long time to come. Our data is safe. Sorry.
Jon Kirwan
<HBBr...@t-online.de> wrote:
>On 28.08.2011 07:48, Jon Kirwan wrote:
>
>> actually lost their memories!! I suspect these tapes, even
>> modestly taken care of, will outsurvive many other forms of
>> recording data -- including writable DVD and CDROM.
>
>Well, except maybe that the amount of paper needed to hold the content
>of a single DVD could be heavy enough to _crumble_ under its own weight,
>if doesn't crash right through the floor before that. The paper to
>store a non-negligible DVD collection might just have enough mass to
>collapse itself into a black hole ;-P
>
>It's one of those "the internet still can't beat a 747 full of DVDs on
>bandwidth" kinds of argument. Yes, well-made books can outlast a lot of
>higher-density archive media --- but what good does that do you with
>data being produced at a higher bandwidth than the trees can be grown to
>make the paper to print them on?
A point, were it that I wouldn't be selective about what I
wanted to last so long. But I could be. of course, I'm not
planning on going out and making papertape my storage of
choice. Just going out and having fun, right now.
>> Well, I need to build up a linear light system -- long
>> filament followed optically by a glass or plastic rod
>> (cylinder lens) to reimage the filament onto the detectors as
>> a bright line.
>
>A "point" source parallelized by a spherical lense/mirror and then
>focussed onto a line by a cylinder might be a whole lot easier ...
Focal distance from the rod would be half the distance that
way. But it would allow the use of an LED light source,
perhaps. I'll play with it. Thanks. But it will also work
with a cylinder (rod) alone, given a line filament (which is
not abnormal for incandescent lamps.) So I have options, I
guess.
Jon
Hans-Bernhard Bröker
> On Sun, 28 Aug 2011 19:46:33 +0200, Hans-Bernhard Bröker
> <HBBr...@t-online.de> wrote:
>> Well, except maybe that the amount of paper needed to hold the content
>> of a single DVD could be heavy enough to _crumble_ under its own weight,
> That would depend on how fine the printed "data" on the "pages" would
> be, and how much of the page that print covered.
Not as much as one might think. If the goal is data integrity and
longevity, you can't print too densely. The usual assumption used in
those typical "holds that many typed pages" is on the order of 2 KiB per
page. Go much higher than that and running ink or other processes will
destroy the data's readability over time just as easily as stray UV
light probably did with Jon's EEPROMs
> Now, those systems move a LOT of data.
Don't tell me about it. My background is high-energy physics. My
former colleagues at CERN basically get to define what "high data rate"
means. There's not many other people who will use "Exabyte" in the
plural form --- and feel no need to explain that it's not 8mm data tape
cassettes they're talking about.
My Name Is Tzu How Do You Do
<HBBr...@t-online.de> wrote:
> The usual assumption used in
>those typical "holds that many typed pages" is on the order of 2 KiB per
>page. Go much higher than that and running ink or other processes will
>destroy the data's readability over time just as easily as stray UV
>light probably did with Jon's EEPROMs
You're fucking lost.
"running ink"
You have to be trolling.
DVD = digital data
Digital data = 1s and 0s
1s and 0s can be dots and no dots.
Dots and no dots can be easily an order of magnitude more dense than
your lame description of stats meant for READABLE TEXT.
Get a clue.
John Larkin
You have this weird compulsive need to be wrong. I mean, you must have
a good magnet somewhere, and some US currency, so you could have tried
it. But you didn't.
Try it.
John
whit3rd
[about magnetite as a black pigment]
> It is not magnetic on US currency EITHER.
Nice try, but I have a magnet and a dollar bill. The
bill is attracted. I'm unwilling to try the experiment on
toner (it's messy).
The classic recipe for black ink, using oak gall, makes
a colloidal iron-based black ink. The particle size might
not be suitable for ferromagnetism, but the material
is black iron oxide (magnetite).
My Name Is Tzu How Do You Do
My birds stream OUT (and in too) over 300Gb/s across several tens of
miles bigger gaps to tens of thousands more endpoints quite remarkably,
in fact.
Your hula hoops gather ten times that amount of data fed from thousands
of transducers, and pass it into huge supercomputer data processors over
short distances hard wired before feeding that pre-compiled data into
still enormous data streams into yet more supercomputers so that you guys
can sit at wonderfully crafted graphics processing monster computer
'workstations' allowing huge numbers of scientists to visualize the
collisions, and work with the data that created the graphics renderings
so we can make a feeble description of the BIG FART that started our
little corner of the macroverse.
Good luck getting it right. It has been fun watching it all (from a
distance).
Jon Kirwan
<HBBr...@t-online.de> wrote:
>The usual assumption used in
>those typical "holds that many typed pages" is on the order of 2 KiB per
>page. Go much higher than that and running ink or other processes will
>destroy the data's readability over time just as easily as stray UV
>light probably did with Jon's EEPROMs
That's silly and unnecessary exaggeration, Hans-Bernard. Such
taken-to-extremes language only works to undermine one's
credibility than to make a non-sequitur, but true point any
better. It is better said without being careless.
I have here a Cauzin Reader that was for a short time used to
transmit data in magazines to their readers using easily
printable marks registered in mass produced publications on
cheap paper and lousy ink. 1985, or so And it provided 1k
bit per square inch. 160 square inches on both sides of a US
letterpaper would be 160k bit or 20k byte using simple
optical means. This is an order of magnitude beyond what you
are saying and even at that it probably can still improved.
Certainly, using reasonable quality paper and modern methods
of fused plastic ink even that could be improved along with
retaining millennia lifetimes.
http://en.wikipedia.org/wiki/Cauzin_Softstrip
(My unit still works just fine, by the way.)
Even an ancient papertape achieves 10 bytes per square inch.
And this is with huge holes and I can read them, if perhaps
slowly. About 1k byte for an 8.5x11 area, punching very huge
holes (which could itself be readily and greatly improved
upon where there some interest to do so.)
The ViewPlus Tiger embosser combines dot height adjustments
(it's like Braille) in 8 heights discernable as distinct by
fingers (3 bits per dot.) The dot density is 400 dot/in^2
and so may arguably deliver 1,200 bit/in^2. At that 160 sq
inch size, that's 24k byte, and the reader is a human finger!
Again, an order of magnitude over you figure and from another
existing product already out there in the field.
But besides flogging a dead horse, it's also different horses
for courses. So I'm just writing this to be argumentative.
It's better not to speak in such extremes, is all. Your
non-sequitur point remains.
Jon
Jon Kirwan
><snip>
>The ViewPlus Tiger embosser combines dot height adjustments
>(it's like Braille) in 8 heights discernable as distinct by
>fingers (3 bits per dot.) The dot density is 400 dot/in^2
>and so may arguably deliver 1,200 bit/in^2. At that 160 sq
>inch size, that's 24k byte, and the reader is a human finger!
>Again, an order of magnitude over you figure and from another
>existing product already out there in the field.
><snip>
It would however be 80 sq inch per page, given this is
Braille form. So perhaps 12k byte per page. Points remain.
Jon
George Herold
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Sun, 28 Aug 2011 00:36:12 -0700, josephkk
>
>
>
>
>
> <joseph_barr...@sbcglobal.net> wrote:
> >On Tue, 23 Aug 2011 15:25:19 -0700, John Larkin
>
> >>On Tue, 23 Aug 2011 15:18:40 -0700 (PDT), "langw...@fonz.dk"
> >><langw...@fonz.dk> wrote:
>
> >>>On 23 Aug., 22:21, John Larkin
> >>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> >>>> On Tue, 23 Aug 2011 20:32:10 +0100, "Ian Field"
>
> >>>> <gangprobing.al...@ntlworld.com> wrote:
>
> ><snip>
> >>>> The OP could paint the box black with one of those and see if the
> >>>> temperature changes much, thermocouple somewhere inside maybe.
>
> >>>> John
>
> >>>I wonder if something like clear Polyurethane would make a difference?
>
> >>>-Lasse
>
> >>Most organics are pretty opaque (high e) at thermal wavelengths, but I
> >>don't know about that one. Black plastic garbage bags are almost
> >>transparent!
>
> >>John
>
> >Could you post something like your visible and IR comparison pics that you
> >once did for kapton film/tape?
>
> >?-)
>
> This is fun:
>
> http://www.youtube.com/watch?v=6mV4ecEbV1s
>
> One other interesting thing: water, ice, and snow are black at thermal
> wavelengths, e around 0.98.
>
>
> - Show quoted text -
Thanks, John.
Nice video Bill.
George H.
josephkk
wrote:
That is why i recently bought a good scope when the opportunity came up.
Now i want another that is portable. I really need to get to work on my
"fancy thing" (just a hobby project really, but [to be] implemented with a
PIC). I'll post when i get it running, may be a while though.
?-))
Ecnerwal
John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
> One other interesting thing: water, ice, and snow are black at thermal
> wavelengths, e around 0.98.
>
> John
Hmm. And yet (perhaps though conversion from energy absorbed at higher
wavelengths downward) spreading ashes on snow to lower its albedo makes
a huge difference in snowmelt rate (personal observation, repeated over
40-odd years with wood ashes, mostly, and things that are not worth
shoveling, but would be nice to get the snow off of a bit ahead of the
default rate.)
--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.
John Larkin
<MyName...@ReplaceWithMyVices.Com.invalid> wrote:
>In article <luuk571rjfn2g9dqa...@4ax.com>,
> John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>> One other interesting thing: water, ice, and snow are black at thermal
>> wavelengths, e around 0.98.
>>
>> John
>
>Hmm. And yet (perhaps though conversion from energy absorbed at higher
>wavelengths downward) spreading ashes on snow to lower its albedo makes
>a huge difference in snowmelt rate (personal observation, repeated over
>40-odd years with wood ashes, mostly, and things that are not worth
>shoveling, but would be nice to get the snow off of a bit ahead of the
>default rate.)
Snow obviously reflects visible light, which is where most of the
sun's energy is, and crud will downconvert that to heat before it get
reflected.
The great majority of CO2 alarmists are determined to ignore what is
probably an equal or greater contributor to polar ice/glacier melting,
which is man-made particulates. But particulates could be controlled
without destroying civilization, so the crazies aren't as interested
in them.
My wife *enjoys* shoveling snow! Am I lucky or wot?
John