Marriage proposal using custom reverse geocache box
The unit, which is made out of a wine box, is unlocked by three servos that actuate rods to release a trio of clasps. His not-yet-fiancé had to first input the correct sequence on a keypad, then turn potentiometers to the right position, and finally traipse to the accurate location—sensed via GPS—for it to open up.
As the project’s I/O requirements went beyond a single Uno, Robertson linked a pair together using the I2C protocol, allowing the master to read GPS coordinates and control a small LCD screen, while the second Arduino takes care of user input and servo actuation.
The result was a “yes” to the proposal, and while we can’t guarantee the same outcome if you build one yourself, more info on the contraption is available here. Congrats, Josh!