Most of my projects start with a simple question: can this be done with parts I already have on my desk? This one began the same way — a handful of wooden picks, a spare N20 motor, a small Li-ion battery pack, and a weekend of CAD tinkering.

What came out of it is a compact, fully 3D-printed pick-throwing device that loads, cocks, and fires with the press of a button. No springs from a clothespin. No rubber bands stretched to their limit. Just a clean rack-and-gear mechanism driven by a tiny DC motor.

Why I Built This

I've seen plenty of toothpick and matchstick launchers online. Most rely on spring tension from a modified clothespin — clever, but inconsistent. The release force varies depending on how far you pull the pin back, and the whole thing feels fragile after a few dozen shots.

I wanted something more deliberate. A device where every shot feels the same, where the motor does the heavy lifting, and where the 3D-printed frame holds everything together without wobbling apart on the third use.

Wooden picks turned out to be the perfect ammunition. They're light, cheap, uniform in size, and satisfying to watch fly across a room.

How It Works

The core idea is straightforward: an N20 gear motor spins a pinion gear that drives a rack linearly. The rack pushes a mouser (the sliding pusher arm) forward, launching the wooden pick out of the barrel.

1. Power on — the battery supplies current to the N20 motor through a simple on/off switch.
2. Motor spins — the gear on the motor shaft engages the rack teeth.
3. Rack slides forward — this pushes the mouser, which strikes the pick seated in the barrel channel.
4. Pick launches — the pick exits through the head/nozzle at the front of the body.

When you release the switch, the motor reverses direction (or you manually reset the rack, depending on your wiring) and the mechanism returns to the loaded position, ready for the next pick. The whole cycle takes about a second.

3D Printed Parts Breakdown

Every structural component is 3D printed. I designed the parts in CAD and iterated through several versions before landing on the files I'm sharing below.

Print Settings I Used

• Material: PLA
• Layer height: 0.2 mm
• Infill: 50-70% for body and head; 60% for gear, rack, and mouser
• Supports: No
• Total print time: ~3–4 hours for the full set

Electronics — What You Need

No Arduino, no MOSFET, no PWM — just direct drive. The N20 draws well under 500 mA at load, so a single 18650 cell handles dozens of shots before needing a recharge.

Assembly Guide

1. Print all six parts — dry-fit the gear onto your N20 motor shaft before gluing.
2. Mount the motor — press the N20 into the fixation bracket and secure inside the body.
3. Install gear and rack — spin the motor by hand; the rack should travel smoothly.
4. Attach the mouser — connect it to the front end of the rack and cycle once by hand.
5. Fit the head — load a wooden pick into the barrel channel.
6. Wire and test — point at a safe target and press the switch.

Download Free STL Files

All six parts are available for free — latest revision (July 2026) with improved tolerances on body, head, and mouser.

⬇ Download All STL Files (ZIP)

What I'd Improve Next

• Auto-return circuit — limit switch so the rack resets automatically
• Magazine feed — gravity-fed hopper for rapid fire
• Speed control — potentiometer for adjustable launch force
• Enclosure redesign — battery hidden inside the body

There's something deeply satisfying about designing a mechanism in CAD, printing it overnight, and having it actually work the next morning. Six printed parts. One small motor. A battery. And a bag of wooden picks that cost less than a cup of coffee.