Leds find immense (untapped!) application in serial data communication. LedComm aims at applications such as short range communication between mobile phones and smart conference tags. These applications require slower bit rates and extremely short range communication, i.e. a low-cost solution for communication over “The Last Centimeter”. 

In our project, we communicate between two ATMega8 boards. A switch pressed on one board is detected on the other board and the pertinent information displayed. The state of two switches being transmitted is analogous to transmitting 0 and 1 or a MARK and SPACE. Switch 1 pressed can be interpreted as a MARK or 1 and switch 2 being pressed can be interpreted as a SPACE or 0.

The transmitter led, blinks at a certain frequency for the first switch and another frequency for the second switch. The receiver detects this frequency and thereby determines which switch is pressed.

The ATMega8 boards, on which our LEDcomm experiments were conducted, are designed by Asst. Prof. Gadre for the "Hello! World of Microcontrollers" workshop, that he conducts annually.