[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
http://www.atmel.com/dyn/products/product_card_v2.asp?part_id=4198
http://www.atmel.com/dyn/resources/prod_documents/doc8271.pdf
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.)
Christoph
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