Claudio Martin wrote:
> Hi all
> Does anybody have a scheme for a cheap movement sensor? Thanks in advance.

You can modify the sensor head from an infrared motion detector
spotlight like the one sold by Wal-Mart for $9 to run on 5V and give an
active-low output.

See http://www.seattlerobotics.org/encoder/nov98/pirhack.html

-Chris

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