Project · Prop build

Proton Pack

A full-size Ghostbusters Proton Pack I’m building from scratch. It’s modeled in CAD (Onshape), 3D printed on a Bambu Lab A2L, and will run on ESP32s for lights and sound. It’s based on Stefan Otto’s prop plans.

In development Updated Oct 13, 2026 Onshape 3D printing Bambu Lab A2L ESP32 Prop

The 3D-printed proton pack so far, flat on a wooden table: the upper modules, the frame and the cyclotron housing ring, all in dark gray — Where it stands: the printed modules, frame and cyclotron housing ring, test-fit together.

The design (CAD)

The whole pack, modeled in Onshape.

CAD render of the full proton pack at an angle, mostly blue, with the power cell and the cyclotron ring in orange and the front crossbar in tan — Angle Shot: the full pack modeled in CAD. The colors don’t mean anything; the orange cyclotron ring is left over from when it was one large part, before I split it.

CAD render of the proton pack seen straight from the front — Front Shot.

CAD render of the back of the proton pack with the motherboard plate hidden, showing the frame and module layout behind it — Rear Shot Without Motherboard: the motherboard plate is hidden to show the layout behind it.

Build progress

Assembly 1: the first printed pieces of the pack test-fit together on a table — Assembly 1: first pieces test-fit together.

Assembly 2: the pack from above with more modules added, including the long tube and the side box — Assembly 2: more modules added.

Assembly 3: the pack at an angle with the right-side modules attached — Assembly 3: right-side modules join.

Assembly 4: the pack from above with the lower frame section added below the modules — Assembly 4: the backplate section takes shape.

Assembly 5: the pack from above with the large ring for the cyclotron housing fitted at the bottom — Assembly 5: the ring for the cyclotron housing fits in.

Assembly 6: the pack from above with the Clippard valve added to the plate, next to the cyclotron ring — Assembly 6: the Clippard valve added.

Done

Cyclotron Spacer
Cyclotron & N-Filter
Power Cell-Injectors
Booster & EDA Box
Ion Arm
Gearbox
HGA
Cosmetic Plating
Gun Mount
Bumper
Booster Frame
PPD & Clippard
Corner Plate & Shockmount
The assembly plan (partly)
Motherboard (aluminum backplate): mostly done

Remaining

Finishing the motherboard
Genuine parts to buy
All electronics

The motherboard

Electronics plan

Not built yet. This is the plan; none of the electronics exist so far.

An ESP32 “brain” in the Ion Arm.
A DFPlayer and SD card in the gearbox for audio.
A second ESP32 in the Neutrona Wand for the wand logic.
A 4-wire link between the pack and the wand: 2 for power, 2 for serial.
A rotary-encoder crank knob that scales the audio with how fast it’s turned.

How the pieces will connect.

Decisions

ESP32 instead of a Raspberry Pi: it’s cheaper and simpler, and the build doesn’t need that much compute.
A serial link between the pack and the wand: it needs only two data wires, so the whole hose stays at four wires, and the wand runs its own ESP32 and just sends events instead of needing a wire for every light and button.

What’s gone wrong

Minor print problems with supports and overhangs while I dialed in a new printer I bought just for this project.

Finish the aluminum motherboard, buy the genuine parts, and build and test the electronics. The Neutrona Wand will get its own page later.

Credits

Based on Stefan Otto’s Prop Plans. The plan files aren’t shared here; get them from the source.

This is an unofficial fan project. Ghostbusters is a trademark of its owners, and this build isn’t affiliated with them.