Mimic RC — A Chest That Guards Your Candy!

A toothy maw, huge eyes, and an enormous red tongue that swings out in an arc. The candy in this chest has its own guardian — with quite a personality!

This project combines 3D printing with RC modelling. The operator controls the lid and tongue using an RC transmitter, deciding when the chest “wakes up”. The design can also be expanded with automatic controls, allowing the chest to react on its own and operate autonomously. Reach inside to grab some candy — and the guardian might just show you its character while you do.

A few simple mechanisms bring the whole performance to life:

• Moving lid, lifted by two micro servos. Their servo horns support the lid from underneath, while gravity closes it. The lid can also be opened freely by hand to refill the candy.

• Cartoon tongue that swings out in an arc, driven by a single servo with a horizontal axis of rotation.

• Two eye options: a ready-made animated eye module or printed eyeballs with vertical monster pupils. Choose whichever version suits the parts you have available.

• Teeth around both halves of the chest, mounted on frames that are glued into place. A gap at the front of the lower frame provides clearance for the tongue.

• Wood-grain texture and separate studded fittings, which can be printed in a different colour and glued into the matching recesses.

The printed eyes consist of a hollow hemispherical eyeball and a separate press-fit pupil. The eyeballs are glued into place from inside the lid, using the same Ø32 mm openings provided for the displays. A rear flange sets the mounting depth. The complete chest requires two eyeballs and two pupils. These parts are printed separately, so you can make white eyes and black pupils without an MMU or any filament changes during printing.

I wanted the model to be convenient to build and modify later. That is why the servo mounts are separate parts glued inside the chest. They can be replaced or adapted to suit your servos without reprinting the body.

The receiver and battery fit beside one of the side walls, beneath a removable cover held in place with hook-and-loop tape. A separate U-shaped divider separates the tongue’s operating area from the candy compartment. A cutout in its side provides clearance for the servo.

The body and lid are printed separately. Both are sized to fit the Prusa MK4S build plate. Separate fittings, tooth frames, tongue, and other components let you choose your own colour scheme.

To bring the model to life, you will need:

• an RC transmitter and receiver that allow independent control of the lid and tongue, or a local controller;

• three micro servos: two for the lid and one for the tongue;

• a suitable power supply and wiring;

• screws for the hinges and servo mounts, glue, double-sided tape, and hook-and-loop tape.

The animated eye version also requires a ready-made display module. In the printed eye version, the eyeballs and pupils are fixed in place.

The tongue servo mount is designed for a TowerPro 9 g micro servo. If you use different servos, check their dimensions and adapt the mounts as needed.

The project includes assembly drawings, an exploded view, a parts list, and details of the tongue mechanism and hinges. A separate sheet shows how to install the printed eyes, including a cross-section through the lid, the flange used for gluing the eyeball into place, and the press-fit pupil.

The chest was created for Halloween, but it can just as easily guard treasures during an RPG session, join an adventure game, or simply sit on a shelf and eye everyone at home with suspicion.

If you build your own Mimic, share some photos of your print. I would love to see the colours and personality you give the next candy guardian! 👀