This is a simple method for controlling a camera flash using an Arduino. The nice thing about this method is that it uses an optoisolator to separate the Arduino from potentially high voltage spikes produced by the flash. I choose to use and optoisolator instead of a relay because the response time is much quicker, which is important when dealing with split second camera timing. Being able to control a camera flash in this manner is not only useful for Photography, but can come in handy for making a haunted house display (and miscellaneous hijinks).

Step 1: Go get stuff

You will need:

- Arduino
- Camera Flash (with input jack)
- Breadboard
- MOC3021 optocoupler (Triac)
- 220 ohm to 1K resistor
- 3/32" mono plug
- Solid core wire
I am trying to build this but would like to order the parts through a particular website, will any optocoupler work? or can i use a transistor maybe? THANKS!!
I know this one works. It may not work with other types. You can perhaps test and see. Not all optocouplers have the same switching mechanism inside.
Ok i am reading everything i can find on optocouplers and continue to be baffled, the ratings on the couplers seems to be about 1.25v yet the arduino will output a HIGH of 5v, so how is your system not failing? Not criticizing your design just trying to understand and obviously something is not clicking for me, thank you!
You are basically powering an LED. You will need to add a resistor in series with the photodiode in the optocoupler.
Maybe this is a stupid question.. but what does the 'to 1K' part of the resistor measurement mean?
1,000 ohms
oh. So it can be any value between these?
You are basically just adding a safe level of resistance before an LED
The trigger port baffles me, I have not seen one on any flash! Would it be possible to create an alternative, for example, with an off-camera shoe mount or some such?
You can buy hot shoe to PC flash sync cable adapter mounts.
Pretty neat! The search for unintended use for a flashlight starts here...

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Bio: My name is Randy and I run the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
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