Cant trigger Fuji disposable flash

Hi there

Firstly I am a complete noob when it comes to electronics, yet I am currently a Com Sci student(1st Year). I am currently building this project with the arduino; But because I came from a rural area and only going back to university in a few weeks I've substituted the optoisolator with a transistor. The circuit works with an LED in place of a flash, however when trying to trigger the flash nothing happens, I am not sure if I can narrow this down to A) Not enough power to the flash. B) Connected the wires at the wrong points (IE, the two points that touch to trigger the flash, however these points are not soldered). Any advice would be appreciated.


What is the voltage across the flash trigger terminals? Did you check polarity before connecting the transistor?

I've tried the the + and - wires on each, I have no way to check them properly. I have Tried firing them from just 'Pin 4' as originally suggested, as an after thought tried adding 5V after the transistor and before in series with the right pin of the transistor.


Thought I didn't have the GND in the right place, continued to try different solutions but it's still not firing. I can fire the flash manually, so there is defiantly nothing wrong with the flash itself. Still isn't working though. It's fired at a few strange intervals but not where it should.

I've tried the the + and - wires on each, I have no way to check them properly

Until you do have a means of checking them, can I suggest you suspend your experiments?

I've done just that, I ordered some tools which will hopefully be here by the end of next week so I won't be kicking around in the dark for long. Thanks for trying to help though.

I usually use MOC3020 opto-triacs to trigger flashguns. Being a triac, the output is not concerned about polarity.

Thanks, I'll try get my hands on one when I'm back at university. The only reason I was trying the transistor is because I literally only have one transistor and a few resistors. I've started another project until I have the right equipment for this one, I have to say though the Arduino has to be most additive thing I have ever come across! I'm loosing sleep at the moment haha

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