LED’s Are My Friend
October 14th, 2005
Multi-Touch Sensing through LED Matrix Displays
Two scalable techniques for enabling ordinary LED matrices to simultaneously act as multi-touch input devices. In 1977, Forrest M. Mims reminds us in one of his “Engineer’s Notebooks” that LEDs can also be used as photodiodes…
http://mrl.nyu.edu/~jhan/ledtouch/
Thanks to Newstoday