The Digital Spray Can was an idea that I had back in 2011, and was used publicly at the reopening of the Wagga Art Gallery in August. Since the cans have gone through several changes to improve their functionality.
The Digital Spray Can uses the controller from a Nintendo Wii and adapted Digital Whiteboard software. The current cans are the 4th iteration and are robust enough to handle whatever the public can throw at them.
The Digital Graffiti Wall in action in my kitchen, I using the gear I had on hand. In reality, I could have probably done with more space and a brighter projector. Works best at about double that size.