[Noisebridge-discuss] Electronics Question

[macegr]

Phil,

Based on the datasheet, 4.7K is probably too high. I would go closer to 1K with that, 2K maximum. I am not sure at all how you arrived at 33 ohms, it would be a bad idea.

If you use the correct values and it still doesn't work, please consider that if you wired it wrong at any point, even for a split-second, it could have permanently damaged the part. But definitely do some testing before making that assumption.

--- Garrett

On Sep 22, 2013, at 9:22 PM, Phil Spitler <phil at bonfirelabs.com> 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
> 
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> 
> 
> 
> 
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> 
> 
> 
> 
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