[Noisebridge-discuss] Electronics Question

Phil Spitler phil at bonfirelabs.com
Mon Sep 23 05:17:13 UTC 2013


I had a 220ohm laying around and still no dice. Hopefully I'll have time to drop by CHM tomorrow to see if somebody there can help me figure it out.

If my opto isolator is fried, does anybody know if there are any in the Noisebridge components selection?

Cheers.

Phil

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

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On Sep 22, 2013, at 9:46 PM, Davidfine wrote:

> With an opto isolator you're really just powering a small LED inside the packaging. Something between 1k and 150 ohm will probably not burn it out too quickly - use the highest resistance that triggers it solidly. And try it without the arduino first (but with a resistor).
> --D
> 
> On 9/22/13 9:22 PM, Phil Spitler wrote:
>> 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
>> 
>> Website | Facebook | LinkedIn
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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