Student Eiji Hayashi has created a very simple, yet unique form of electronic game based around an Arduino-compatible board. The display is generated using an 8 x 8 LED matrix display – nothing unusual there. However the LEDs also act as the input device by a method which is generally unknown until now. What we do know is when a current is applied to an LED – it lights up. However Eiji demonstrates that when a bright light is applied to an LED, such as that from a laser pointer – the LED generates a small current. This can then be measured using analogue inputs of the Arduino board, therefore giving us a form of input.
By rapidly switching the Arduino pins that are connected to the matrix between input and output types, the LEDs can then operate as a display and also a form of input at a rate which appears to be almost simultaneous. Taking advantage of this, Eiji has created a simple game where you use a laser pointer on the LED matrix to ‘shoot’ pixel aliens, and other controls. Watch the following video for his demonstration:
Using this method is very simple, and the size of any possible matrix is only limited by the number of analogue inputs on your microcontroller. For example – you can have an 8×8 matrix with an Arduino Mini or Nano board – or using an Arduino Mega you could have a larger 16×16 matrix. So get yourself a laser pointer, then for all the details including schematic and Arduino sketches head over to Eiji’s website here. http://www.cs.cmu.edu/~ehayashi/projects/lasercommand/