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Topic: Arduino based Stereo Canon DSLR Interval Trigger (Read 3606 times) previous topic - next topic

NNC1

I am trying to build a 2 camera Canon DSLR Trigger that will trigger both cameras instantaneously at a regular interval. I don't know which cameras will be used as this point but since they all follow the same sync the conductor standard, it really doesn't matter for now.
I have adapted the schematic from: http://www.paulodowd.com/2013/02/arduino-remote-trigger-for-dslr-stop.html
I plan to use a Adruino Uno Rev3 unless there is a better choice.

However, I unfortunately know almost nothing about circuit design and choosing parts. (Hopefully I can learn something from this project  :))

I have uploaded the schematic I made here:
https://www.circuitlab.com/circuit/9s9x8k/unnamed-circuit/
https://www.circuitlab.com/circuit/9s9x8k/screenshot/1024x768/


I have several questions:

  • Should I change something in the schematic?

  • What parts should I use for relays, optoisolators, etc. ?

  • Can someone help me find these parts on mouser or somewhere?

  • There are 9v power sources in the original schematic. I plan to use a 9v power supply for the arduino. Where do I connect for 9v?



I spent quite some time looking for parts on Mouser only to determine I have no idea what I am looking for.
Your help would be greatly appreciated.

jabbado

#1
Feb 14, 2013, 11:00 pm Last Edit: Feb 14, 2013, 11:02 pm by jabbado Reason: 1
Firstly the diodes D1-D4 are unnecessary. They may even cause problems due to the voltage drop across them. However you should put flyback diodes across the relay coils as explained in the article.

I just checked my 60D and the current that flows through the focus and shutter circuits seems to be less than 100uA. So even some small reed relays will do the job.

Optoisolators aren't really needed here since the relays are isolating your circuitry from the camera.

NNC1


Firstly the diodes D1-D4 are unnecessary. They may even cause problems due to the voltage drop across them. However you should put flyback diodes across the relay coils as explained in the article.

I just checked my 60D and the current that flows through the focus and shutter circuits seems to be less than 100uA. So even some small reed relays will do the job.

Optoisolators aren't really needed here since the relays are isolating your circuitry from the camera.


Thanks for the advice.

Schematic Updated.

Shpaget

Just a practical advice. I would not let the camera focus for each shot because one lens may hunt for focus longer than the other and you most likely won't get simultaneous shots.
Set the focus to manual and you need to trigger only the shutter.

I'm also not too sure about connecting the shutter pins together. I'd avoid it, if for no other reason, than just to keep my mind at ease.
An optocoupler such as 4n35 is sufficient replacement for your relays. My guess is they are cheaper and less bulky, not to mention silent. They can also be driven by the Arduino board so you don't need 9V (battery ground should be connected to Arduino ground).

Veco

#4
Feb 15, 2013, 12:21 pm Last Edit: Feb 15, 2013, 12:24 pm by Veco Reason: 1
I agree relays seem a bit heavy duty for this application. I should think that a simple opto-isolator would be fine for switching. When you get the cameras, i'd imagine they have some current limiting already built in, but give it a quick measure like jabbado did and see if you need a resister in series. That way you can get rid of the 9v supply.
Everything else seems fine.

I'd defiantly go for a solid state solution, any bounce on mechanical components like a relay could make your camera do strange things.

jabbado

I'd defiantly go for a solid state solution, any bounce on mechanical components like a relay could make your camera do strange things.


We're talking about Canon cameras here. All fine. Sure I'd use a solid-state solution. But there's nothing wrong with what the OP is doing. It's simple and effective.

sbright33

I have hooked the T2i shutter directly to an Arduino pin thru a 1k resistor.
If you fall... I'll be there for you!
-Floor

Skype Brighteyes3333
(262) 696-9619

NNC1

I have implemented your suggestions and here is Version 2:
https://www.circuitlab.com/circuit/tgqxnr/unnamed-circuit-v2/
https://www.circuitlab.com/circuit/tgqxnr/screenshot/1024x768/



An optocoupler such as 4n35 is sufficient replacement for your relays. My guess is they are cheaper and less bulky, not to mention silent. They can also be driven by the Arduino board so you don't need 9V (battery ground should be connected to Arduino ground).


I switched out the relays with a quad optoisolator (CNY74-4H) instead of the 4n35. Would this work?
Data Sheet http://www.mouser.com/ds/2/427/83526-97631.pdf


Just a practical advice. I would not let the camera focus for each shot because one lens may hunt for focus longer than the other and you most likely won't get simultaneous shots.
Set the focus to manual and you need to trigger only the shutter.


I already planned on using manual focus. The original schematic has an option to disable it. I plan to modify the code to use the button to focus the cameras at once before shooting and not in connection with the shutter.


I'm also not too sure about connecting the shutter pins together. I'd avoid it, if for no other reason, than just to keep my mind at ease.


I changed the schematic so the shutters & focuses are coupled after the optoisolator.
Did you have some other solution in mind?

Thank you for all the help.

Side note: My understanding is a optoisolator is basically the interaction between a LED & a photoresister. Something similar to a LA-2A Compressor?

Shpaget

I am not familiar with LA-2A Compressor, but an optocoupler is basically a (photo)transistor that (in this case) acts as a switch depending on the state of the LED on the other side. The important part is that the two sides are galvanically isolated from each other meaning the current from one side can not enter the other side (as long as you keep within specs) effectively separating your circuit into two.

My Canon DSLR will also focus if shutter pin is grounded (regardless of focus pin) if the lens is in AF, so you might want to put it in MF after all.

NNC1


I am not familiar with LA-2A Compressor, but an optocoupler is basically a (photo)transistor that (in this case) acts as a switch depending on the state of the LED on the other side. The important part is that the two sides are galvanically isolated from each other meaning the current from one side can not enter the other side (as long as you keep within specs) effectively separating your circuit into two.

My Canon DSLR will also focus if shutter pin is grounded (regardless of focus pin) if the lens is in AF, so you might want to put it in MF after all.


Thanks for the explanation.

My understanding is that when in MF, grounding the focus pin will still focus right?
My idea was set camera to MF, set up the scene, trigger focus simultaneously, and then trigger shutter releases simultaneously at regular intervals.

Shpaget

No. In MF autofocus is completely disabled. You would need to either focus manually or use AF then turn it off.
Manual focus  is not so bad, though. Use LiveView if you have it. Set digital zoom to 10x and you can get the focus more precisely than with AF.

jabbado


No. In MF autofocus is completely disabled.


Correct. It's as if the remote pins are connected to the shutter button. Since if you move AF to a back button, grounding the remote AF wire won't focus either.

NNC1

I guess the focus button will only be used for single triggers and not with the interval. Using MF is not a real big deal.


Can anyone look at the schematic and tell me if this looks good?

sbright33

Why not connect D2 thru a resistor to the camera shutter input?
If you fall... I'll be there for you!
-Floor

Skype Brighteyes3333
(262) 696-9619

NNC1


Why not connect D2 thru a resistor to the camera shutter input?


I wanted to use a relay or optoisolator to isolate my cameras from the rest of the circuit.

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