Hardware hacking

http://dangerousprototypes.com/category/maker-faire/

http://dangerousprototypes.com/category/infrared/

http://forums.parallax.com/showthread.php/146879-One-sensor-to-discriminate-Walsh-modulated-IREDs?p=1171544&viewfull=1#post1171544  Uses TSL262R-LF IR to voltage converter.