Toy Converted Into an Enigma Machine
An anonymous reader writes "Enigma machines (the machine Germans used to encrypt messages during World War II) are cool, both from the perspective of the technology behind them and the effort that went into cracking them. This project shows how to convert a toy from a second-hand store into an Enigma machine."
if the hack didn't involve sticking an arduino in it. When you add that part, it's not really a hack anymore, it's just a replacement cover for new internals.
Which is the mechanical aspect. Doing it all in software just doesn't count.