[Cyborg] 200 laser diodes

Christoph Maier cm.hardware.software.elsewhere at gmail.com
Thu Jun 3 06:44:03 UTC 2010

On Wed, 2010-06-02 at 23:06 -0700, Eric Boyd wrote:
> Indeed!  My plan is to basically hack a North Paw board into doing the 
> work, but according to my calculations you should just be able to use an 
> Arduino.  50mW laser diodes.  If we assume they have a 3V drop (the page 
> says "battery: 3-5V"), that means 16.7mA each, which you can drive with 
> an arduino pin.  Anyone know the total power an Arduino can drive/sink? 
>   I'm just wondering how many of the pins you could have going at once...
> Eric

According to 
chapter 22, Absolute Maximum Ratings, 
you can draw up to 200 mA through the power pins 
and 40 mA through any one I/O pin, 
meaning that without a driver, you shouldn't try to drive more than 10
laser diodes directly. 
(Note that an earlier version of the data sheet quoted 300 mA absolute
maximum rating; this means that you can probably get away with driving
more current for a prototype, but NOT repeat NOT for stuff you want to
sell commercially.)


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