We spent the last two weeks building an entry for the Red Bull Challenge that we got submitted 10 minutes before the hard deadline last night. It was a race to the finish to get everything integrated, but we freakin' did it!
It's an Arduino (or in this case, 'Bullduino') controlled box of mysteries and delights with conditional logic and EL wire. Built into a mini refrigerator that was donated to the group, it uses sonar to sense anything approaching an iris at the top (which it then opens) so a pneumatic platform can raise up to receive the can. If you place an empty Red Bull can on it, it drops down into the box, the iris closes, and a barcode scanner tells the processor what the UPC is. If it's a Red Bull can, a solenoid kicks the empty into a recycling hopper and a stepper-motor loading mechanism rotates and drops a fresh cold can into its place.
The pneumatic piston smoothly lifts up through the once-again opened iris amidst a blast of freezing gasses and an ice-encrusted can is ready to be consumed.
If you place a non-Red Bull in the slot, the barcode scanner lets the processor know. Valves close and a pair of air compressors run, building up a charge, then the iris is flung open and the offending can is violently blasted out from inside the box.
It was a blast to build this over the last couple weeks and our team really came together! Great work, everyone!