Flash output control

[Jake]

I have a couple of questions.

1) Using the TTL quench signals, will this allow control of flash
output down to 1/3 stop increments, even for flashes whose manual
control is only in full stops?

2) Will this also allow flash output below the range of manual
control? (For instance, down to 1/128 power?)

I suspect the answer to both is "yes".

[Konstantin]

First is yes, second is probably yes. At very low power settings
chances are you won't be getting consistent results.

[Mathe]

1) yes, no problem. If you have the right timings it's even possible
to make 1/4 stop steps or smaller.

2) yes, 1/128 or 1/256 is not a problem once you have the correct
timings. Even at those small power values the timings vs power are
consistent. But to get the power settings correct you need a stable
and correct clock. That's for one the reason I've chosen to use a
crystal oscillator and not the internal RC oscillator from the atmega.
1/64 and 1/128 is only a 18 us (micro second) difference on the
SB-800.

I'm currently making timing tables for SB22/25/26/28/800 including 1/2
stop increaments all down to 1/128 for all flashes.

Marc

[tim10243]

hi,
I got an idea but not a clou how to realize it:
i would like to have three or four turnable buttons at the transmitter
spot for the manual power adjustment of three or four receiver spots.
why do i want these buttons? i think its more practical to make a test
shot, take a look at the cameradisplay and make a quick adjustment via
turnable buttons instead going with a joystick into a menue.
i would like to know if this is possible? how much work would it be to
change the existing circuit and software? would someone here help me
to do it - to be honest i should ask: would someone here do this for
me?
tim

[Mathe]

Tim,
I think this should be technically possible. You could use
potentiometers for the dials and connect each of them to an ADC input.
But then you'd still need the display and nav joystick to connect a
channel to a receiver by radio.
And all this would require a large amount of software alterations
which is not my cup of tea.
Also take notice that the housing would become bigger with the pots.
My aim is to have a small as possible package on top of my camera.
I know that dials will make change settings a bit faster but in
practice making changes in the menu is also easy and fast.

best regards,
Marc

> > > I suspect the answer to both is "yes".- Tekst uit oorspronkelijk bericht niet weergeven -
>
> - Tekst uit oorspronkelijk bericht weergeven -

[Konstantin]

They don't have to be potentiometers. IMO, encoder wheels would be
better. Or even one encoder wheel.

[Till Seyfarth]

Originally my thoughts went in the same direction (encoder wheels). I'd recommend counting available input pins on the mC as a starting point. Let's say you wanted to encode 8 different values (null, full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64). Encoded that would result in 3 input pins per channel (2^3 = 8; note that realizing half stops would cost twice that). Times the number of channels, let's assume 3: results in 9 digital inputs occupied.

 

Ok, I'll do the pin counting...

 

C0-C5: buttons (=6)

D0, D1: optocouplers

D2, D3: ext. interrupts

D4: free (=1)

D5: LED

D6, D7, B0: display (=3)

B1: free (=1)

B2: slave select RFM12

B3-B5: shared SPI (display, rfm12, isp)

 

So it seems that there are 6+1+3+1 = 11 available pins. Works for 3 channels, doesn't for 4.

 

Software: You'd need to wait for state-changes of the encoder wheels in the main loop instead of waiting for button presses (simple change) and transmit the new power setting on detection (no change here). I'm unsure about the radio protocol though: In case the transmission goes bad (which is detected in the current design) I don't see how this could be visualized to the user. And it should be, because the tranmitter wheel could be in the 1/8 position although the last confirmed power change was 1/4. I can imagine LED blinking patterns encoding success or failure of transmissions... but well. It's not perfect.

 

I like the idea of a simpler SPOT. The display is giving me headaches (mechanically - it's a pain to connect). Perhaps the encoder-wheel solution can work - I just don't see how exactly. I'll help on software side if that's needed.

 

Cheers

Till

[Konstantin]

I was thinking along the lines of a free-spinning wheel. AFAIK two
pins are required to catch forward/reverse movement of the wheel. But
anyway, mechanics is the biggest problem in almost any device, as is
the box :)

[Till Seyfarth]

Ah, ok. That's better, pin-count wise. You'd need 8 pins for 4 channels. That would leave 3 pins which could be used as status info per wheel (we've got one LED already). Blinking for change, on for ok, off for not ok or null power...  alternatively the 3 pins could be connected to a 7-segment display or a row of 8 LEDs and visualize the most recently updated power setting.

 

 I like the idea! So who builds it? I don't know these free-spinning encoders yet, I'll have a look around.

[Stephen Eaton]

What about something along the lines of this nav switch http://www.sparkfun.com/commerce/product_info.php?products_id=8184

 

up/down and push to select.  The push to select could be used set current flash power then select next flash for output power setting. 

 

This way it will not limit you to fixed amout of strobes  i.e. 4 encoder wheels will limit you to 4 strobes. 

 

only down side I can think of is it may become a bit of a pain if you continually need to re-configure power outputs so you need to toggle through list of strobes.

 

Stephen....

 

 

 

---

From: spot-dev...@googlegroups.com [mailto:spot-dev...@googlegroups.com] On Behalf Of Till Seyfarth
Sent: Monday, 10 August 2009 7:28 PM
To: spot-dev...@googlegroups.com
Subject: Re: Flash output control

__________ Information from ESET Smart Security, version of virus signature database 4321 (20090810) __________

The message was checked by ESET Smart Security.

http://www.eset.com

__________ Information from ESET Smart Security, version of virus signature database 4321 (20090810) __________

The message was checked by ESET Smart Security.

http://www.eset.com

[Till_Hamburg]

I've uploaded a preliminary case design ("Case_without_LCD.JPG")

1 Tx/Rx mode switch
4 wheels: power selection in Tx mode, channel selection / manual power
input in Rx mode
8-LED indicator bar for display of power of last changed channel in Tx
mode or display of selected channel in Tx mode

This simplies building the SPOT significantly.

Who's in?


On 10 Aug., 14:19, "Stephen Eaton" <madeino...@gmail.com> wrote:
> What about something along the lines of this nav switchhttp://www.sparkfun.com/commerce/product_info.php?products_id=8184

>
> up/down and push to select.  The push to select could be used set current
> flash power then select next flash for output power setting.  
>
> This way it will not limit you to fixed amout of strobes  i.e. 4 encoder
> wheels will limit you to 4 strobes.
>
> only down side I can think of is it may become a bit of a pain if you
> continually need to re-configure power outputs so you need to toggle through
> list of strobes.
>
> Stephen....
>
>   _____  
>

> From: spot-dev...@googlegroups.com
> [mailto:spot-dev...@googlegroups.com] On Behalf Of Till Seyfarth
> Sent: Monday, 10 August 2009 7:28 PM
> To: spot-dev...@googlegroups.com
> Subject: Re: Flash output control
>
> Ah, ok. That's better, pin-count wise. You'd need 8 pins for 4 channels.
> That would leave 3 pins which could be used as status info per wheel (we've
> got one LED already). Blinking for change, on for ok, off for not ok or null
> power...  alternatively the 3 pins could be connected to a 7-segment display
> or a row of 8 LEDs and visualize the most recently updated power setting.
>
>  I like the idea! So who builds it? I don't know these free-spinning
> encoders yet, I'll have a look around.
>

> On Mon, Aug 10, 2009 at 1:15 PM, Konstantin <beowulfena...@gmail.com> wrote:
>
> I was thinking along the lines of a free-spinning wheel. AFAIK two
> pins are required to catch forward/reverse movement of the wheel. But
> anyway, mechanics is the biggest problem in almost any device, as is
> the box :)
>

> On Mon, Aug 10, 2009 at 2:11 PM, Till Seyfarth<tillseyfa...@gmail.com>

> > On Mon, Aug 10, 2009 at 12:24 PM, Konstantin <beowulfena...@gmail.com>

> > wrote:
>
> >> They don't have to be potentiometers. IMO, encoder wheels would be
> >> better. Or even one encoder wheel.
>

> >> On Mon, Aug 10, 2009 at 12:36 PM, Mathe<i...@vaenw.nl> wrote:
>
> >> > Tim,
> >> > I think this should be technically possible. You could use
> >> > potentiometers for the dials and connect each of them to an ADC input.
> >> > But then you'd still need the display and nav joystick to connect a
> >> > channel to a receiver by radio.
> >> > And all this would require a large amount of software alterations
> >> > which is not my cup of tea.
> >> > Also take notice that the housing would become bigger with the pots.
> >> > My aim is to have a small as possible package on top of my camera.
> >> > I know that dials will make change settings a bit faster but in
> >> > practice making changes in the menu is also easy and fast.
>
> __________ Information from ESET Smart Security, version of virus signature
> database 4321 (20090810) __________
>
> The message was checked by ESET Smart Security.
>

> http://www.eset.com- Zitierten Text ausblenden -
>
> - Zitierten Text anzeigen -

[Jake]

I like this idea a lot. Simpler is better, as far as I am concerned.

Plus, I like the idea of an indicator that can be seen from at least a
few feet away showing the current channel when in Rx mode.

[Jake]

One other thought. This could be further simplified with only one
encoder wheel to change power and a switch (or second encoder wheel)
to change channels. This would make it easy to cycle through the
channels and see the current power level of each. Might also need
some more LEDs (or some other method) to display the current channel.

[Till Seyfarth]

Jake, good idea! Two wheels, one "endless" for power-change (for both Tx and Rx) and one for channel selection A, B, C, D - same for Tx and Rx! The mode-switch could have three positions: Off - Tx - Rx.