Interactive LED Display

 Not directly related to robots but thought this is really cool.

 An interactive full-color LED display made by nahitafu. LEDs are normally used to emit light but they can also become photo sensors because a weak electric current flows when they detect light. So he was able to control the colors of the LEDs depending on how much light they get. According to nahitafu, it's not difficult to do that with one LED, but it's not easy to make it work this nicely in arrays. Look at how it glows when he moves his fingers.

 

 His dream is to make large wall displays with this.