http://www.plazaearth.com/usr/gasperi/lego.htm
http://www.plazaearth.com/usr/gasperi/mux.htm
http://www.plazaearth.com/usr/gasperi/gpa.htm
http://www.inchlab.com/gp2d02_interface.htm  Andreas PETER
http://www.acroname.com/robotics/parts/R48-IR12.html
http://www.infineon.com/cmc_upload/0/000/008/496/sfh484_5.pdf