I used an arduino to develop the spray can, before making a custom board with an AVR 168. Then I used the arduino board for the receiver, making use of the serial->USB connection.
- The spray can has an infra red LED that shines through the projector screen and is seen by the wiimote's camera.
- The wiimote sends the X and Y co-ordinates of the can to the computer via a bluetooth radio link.
- The computer is running a simple painting program that uses a projector to "paint" the lines as you draw with the can. It also takes care of mapping the wiimote camera to the screen using a 4 point calibration system.
- The spray can also detect its distance from the screen and the nozzle pressure: the further you are away the bigger the dot drawn, the harder you press the nozzle, the more opaque the paint dot becomes.