> Also, LEDs can also act as light sensors. Food for thought. As an undergrad, I had to write a 'chat-program' where two LEDs on Arduinos were used for communi

> Also, LEDs can also act as light sensors. Food for thought. As an undergrad, I had to write a 'chat-program' where two LEDs on Arduinos were used for communication; essentially blinking at each other, acting both as sender and receiver. Fun times!