[Noisebridge-discuss] Electronics Question

Phil Spitler phil at bonfirelabs.com
Tue Sep 24 19:32:00 UTC 2013

I never tried the 33ohm, currently the resistor value is 220ohm and it does seems to be triggering the switch it's just that the switch isn't trigger the flash unit.

I am building an Arduino controlled external flash unit for shooting high speed photos.

I tried swapping the outputs but still nothing.

It's driving me nuts and I'm out of things to try (other than ordering a different opto-relay)

Any other ideas? Tips, Suggestions or advice?

I am happy to swing by Noisebridge if somebody with more knowledge than me is interested in taking a look.



Phil Spitler  |  Creative Technologist   |  Bonfire Labs  |  t : 415.394.8200  m : 415.571.3139

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On Sep 24, 2013, at 12:43 AM, Jake wrote:

> phil,
> did you try swapping the "output" pins of the optocoupler?  It is a photodiode in there (not a relay) so it does care about polarity i think.
> it seems like you are being properly methodical, keep it up and you will succeed.
> Your calculation of 33 ohms for the LED side of the optoisolator is probably fine, although 100 ohms would probably work just as well.  You are supplying 5V from the arduino, to an LED (maybe infrared in there) which takes maybe 1.8 volts, at 0.020 amp.  so 5v - 1.8v = 3.2v, and a resistor making 0.020 amps at 3.2v is 3.2 / 0.020 = 160 ohms.  Just my guess without looking at the datasheep.
> what are you trying to make?
> -jake

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