hi there!
i'm trying to control (fire) a flash light circuit from a disposable camera. the flash is going to be fired quite often (as quickly as charge times allow).
problem is that the fire-button connections run up to 160v when charged. i tried a tip120 in combination with a opamp 4n35 but no luck. what would be the best route to go? a relay? if so what ratings should i look out for?
thanks!
F
A relay would be one option make sure the contacts can handle the voltage, the coil would need to be 5V and you would need a transistor to switch it from the arduino.
Alternatively an opto isolator (with a sutiable high voltage ouput) would be a better option.
this guy interfaced a SCR (silicon controlled rectifier) to trigger a camera flash with sound. look at the second part of the schematic, where the opto-isolator is to get ideas.
i dont have much experience with scr's so i cant help much, but perhaps someone else here can get an idea from it.
okay, i'll give the thyristor (scr) a try, although relai might have added a nice sound to the machine. i'll report back with results.
thanks!
F
A relay should work OK, but they tend to be big and rather power hungry compared to semiconductor switches. I want to see sometime whether a typical triac-optocoupler will pass enough current to trigger the strobe without an actual triac as well. It should be a pretty close call, and would be nice and convenient.
relay works perfectly. i now use three 6V (which switches at 5V as well), 16A relays. one drawback is though that it needs some time to actually switch which ist due to the little electromagnet inside. but since this is less than the time when i need to trigger the next flash it works for me.