Detect camera shoot with flash hotshoe

Hello All,

For a photo booth project I have, I would like to allow to see when the camera is shooting.

In fact, I just want to create a fake flash with some led strips. I say fake because the main light is always ON.

My problem is to detect the shooting moment on the flash hotshoe.

I did a wiring that was functional on my Canon 5d2 but is not working on my 50d. I used a digital input with a drop down resistor. Then I connect 5v to one wire of the hotshoe and the input on the other wire.

Do you have some experience with that kind of detection? I’m wondering if it could just be my drop down resistor that don’t have the correct value.

To avoid to much try and errors, I would prefer to profit of your experience to do that :slight_smile:

Thank you very much

It could be the polarity. A pull up resistor would produce a positive sync voltage which would be more common. If you have a pull down resistor, you have a negative sync voltage.

Or you could use a real flash and just set it to manual at 1/128 power. Much easier and a more convincing fake.