Very Low-Cost Sensing and Communication Using Bidirectional LEDs

Uses PICs.
Cute

http://www.beatbutchermpc.com/wp-content/uploads/leds%20as%20photo%20sensor=
s.pdf

MITSUBISHI ELECTRIC RESEARCH LABORATORIES
http://www.merl.com
Very Low-Cost Sensing and Communication Using Bidirectional LEDs
Paul Dietz, William Yerazunis, Darren Leigh
TR2003-35 July 2003
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.