[Noisebridge-discuss] Electronics Question

[Phil Spitler]

Hey list people, I have an electronics question that I wonder if somebody could help me with.


Basically I'm trying to build a high speed photography rig based on this.

http://mattrichardson.com/blog/arduino-flash-trigger-parts-list/

I have fallen at the first hurdle which is to get the opto-issolator to work.

I have a feeling it is due to the value of the resistor I'm using on the input.

I have followed his instructions but it seems like the resistor value of  4.7k might be too high.

I found the data sheet for the opto-issolator here http://pewa.panasonic.com/assets/pcsd/catalog/aqw-dip-2-form-a-catalog.pdf 

And more info here. http://www.digchip.com/datasheets/parts/datasheet/724/AQW280EH.php

I used an online resistor calculator  http://led.linear1.org/1led.wiz and put in the numbers that I found in the data sheet (I think) and it gave me a resistor value of 33 ohms.

When I use the 4.7k resistor the opto-isolator doesn't do anything when the arduino pin goes high but I don;t want to use a much lower value in case I fuck the chip.

Any ideas?

Cheers.

Phil

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

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