This is a puzzle that I quite enjoyed coming up with, it has a nice old world feel to it. It’s simply a channel behind a dart board, with a magnetic plunger that releases a key when the magnetised medal is placed on it.

The channel and plunger are 3D printed, there is a magnet inside of the tapered plunger which travels inside of the outside sleeve.

The plunger sleeve protrudes out into the bulls eye cavity in the dart board and is covered in red felt so that it looks just like a real dart board.

When you place the war medal, which has a magnet glued to the back onto the bulls eye, the plunger retracts, and the key drops out.