The client wanted a box that would open, play a sound and give the guests a bottle of wine for their efforts in playing. The tokens would be unlocked and given to guests for solving various puzzle, and once they had 5, they would search for this box, slip their tokens in, and get loaded up on wine for the night.

As you can see, this is totally under-engineered! I’ve got five 3D printed token holders with micro-switches which then power an arduino nano from a rechargeable lithium cell. The arduino immediately powers the servo and opens the lath, then listens for an input from the magnetic switch to trigger the lights and audio once the lid is opened.

A little 3D printed micro-switch token slot mechanism.

A little bend on the micro-switch lever and we are good to go, the micro-switch also provides enough tension on the tokens to stop them popping out when the lid is opened.

I used the metal hinges to transfer power from the lid to the LED lighting strip inside the box, this saved having an ugly and exposed wire.

I knocked the box up out of some pine that I dressed down on the thicknesser and ripped up on the table saw. The slots in the lid were cut out oldschool with a coping saw, because that’s just how I roll.

I 3D printed a little latch mechanism that allows the locking bar to slide over under spring tension and lock.

You can see how the latch works, it’s a 3D printed bar that swings when pulled by the servo, and always has spring tension gently pushing it closed to allow it to slide over the tapered locking latch on the box. The magnetic switch, relay for the lighting strip, MP3 module, servo, battery, and speaker are all snugly mounted under the cover panel.

I made up a nice little 3D printed jig for drilling the speaker holes, and made an access hole for the micro USB charging socket. The LED strip with its hidden wires camouflages in there nicely after a coat of stain. The tokens are just discs of 6mm plywood cut using a hole saw in a guide without the center drill. A bit of hay in the bottom to cushion the bottle adds to the charm.