Flash Trigger Box

Attached is a photo of my Flash Controller Box up and running. In the photo the mode used was “Fire All”.
Might be able to post photo later of it in use against a wall if the weather allows me (unsure if I have enough sand bags to weigh everything down for shoot). Attached is also a view (unpowered) of the top and a third showing inside the “lunchbox”

The wire in the bottom left is the camera sync lead. The four flash sync leads plug into the four “flying” leads (as can’t get these from Jaycar - had to cannibalise some sync leads to get the female ends.

It currently has four modes 1) fire all flashes at once, 2) fire one specified unit, 3) fire all sequentially with a specified delay between each, 4) fire each flash in turn, cycling through them firing one unit per camera trigger.

It consists of a Yourduino board with a freetronics terminal shield for connections and protoboard space for the analog voltage ladder for the switches (as the lcd onboard buttons were too small), A Freetronics 16x2 LCD Module and a YwRobot 5v 4-relay relay board to switch the flash sync trigger lines. along with 7 m/o push button switches and an on/off switch.
Power is via USB when programming updates and 6v battery cluster when in use.

Resized images to a more browser friendly size

Too big - can't see what it is. Resize to about 1000 wide.

Apologies - I'm used to working with larger sized images when doing my artwork in Photoshop and posting them on Deviant Art - It didn't occur to me to resize them. I have edited my post to downsize the images.

Much better.

Just been outside to do some tests. Had to try to ND filter the yellow flash as it had limited power control and was dominating.(the biggest 2 had manual power output settings such as 1/4 1/2 3/4 full power. Just used portable flash guns as I wasn’t going to lug my studio lights outside (and I didn’t have enough sandbags for all the stands and tripod).

Flashes were set up to minimise light-spill to minimise disturbing the neighbors, hence I couldn’t use the back yard as the adjoining unit has a toddler and didn’t want to risk disturbing them with flashes of light. (called being considerate)
I firstly set to cyclic mode so I could see each unit was firing seperatly, All-fire mode for a shot and discovered yellow was overpowering. I then used solo mode on flash 4 while I tried to reduce it’s output and finally sequential to capture the attached shot.

This was a 5 second long exposure at F3.5. Flash Box Mode was sequential with 1 second delay between units.
I wanted to grab a friend of mine and head over to a park about 20min walk away but he was busy, so had to use a stone wall out on the street outside our house. If I had used the park, I could have set a longer exposure with a between unit delay of 2 seconds and had him walk across in front of the camera which would have him register 4 times with each time being a different color.

Very cool idea. Also I'm feeling a little better seeing that others also raid Coles for project boxes now :)

Was there a reason you chose relays rather than something solid state, like MOSFETs (say) on the triggers?


Hi, The relays gave me physical isolation between the low voltage area of the Arduino and the potentially high voltages of the flash trigger signals.

In a flash gun (or speedlight) a voltage is sent down a wire to the camera. In the camera is a switch system, when the shutter fully opens, that switch closes, thus enabling that voltage to return to the flash gun. When the flash gun recieves that voltage (the signal goes high) the flash fires. In older Flash guns this trigger voltage can be up to a 1000 volts (but only a very ting amperage). Thus most of the ones I have lying around can't be used directly on my dslr's. Thats why I have a WEIN safe shoe on my camera which protects the camera from these high voltages (it also gives me a sync lead socket on my camera)..