A motorized pet food dispenser that mounts onto an off-the-shelf clip-lock plastic container
(~1.7 L / 60.5 oz, the kind sold at Dollarcity). A motor drives a worm screw, which turns a
crown wheel at a reduced speed and a right angle — that crown wheel is keyed to a feed screw
(auger) that pushes kibble out through the front outlet. The worm/crown mesh also keeps the
auger from free-spinning when the motor is off, so food doesn't dribble out on its own.

Features

• Mounts onto a standard ~1.7 L (60.5 oz) clip-lock container — no custom container needed
• Worm-gear driven auger: consistent portions, self-locking when idle (no gravity feed/spill)
• Compact footprint: base is ~102 x 102 x 57 mm
• Fully printable mechanism — only the motor and a few electronic parts are bought
• Raspberry Pi Pico W controlled, so dispensing can be scheduled or triggered remotely
• Editable STEP file included so you can adapt it to your own container or motor

What You Need

The container

• 1x clear clip-lock plastic food container, ~1.7 L / 60.5 oz (bought at Dollarcity)

Electronics

• 1x Raspberry Pi Pico W development board
• 1x TIP31 NPN transistor (switches the motor from the Pico W's GPIO signal)
• 1x small DC gear motor, mounted to drive the worm screw
• 1x 12V power adapter (powers the motor circuit)

Printed Parts

Electronics Overview

The Raspberry Pi Pico W drives the TIP31's base (through a current-limiting resistor) to switch
the motor on and off. The motor and TIP31's collector run off the 12V supply; the Pico W itself
can be powered from its own USB/5V input, separate from the 12V motor line.

Note: a flyback diode across the motor terminals is recommended to protect the TIP31 from
voltage spikes when the motor switches off.

The electronics are open — build your own version however fits your setup. If you'd like the
schematic or exact wiring, leave me a comment or send a DM and I'll share it.

Assembly

1. Print all seven parts.
2. Mount the worm screw on the motor shaft.
3. Install the crown wheel and feed screw assembly into the base, meshed with the worm screw.
4. Fit the guide and washer on the drive shaft.
5. Attach the hopper on top of the base.
6. Secure the housing onto the container's clip-lock lid.
7. Wire the motor through the TIP31, controlled by the Pico W, powered from the 12V adapter.
8. Fill the container and test the dispensing flow.

Notes

• The worm/crown reduction is what keeps the auger from free-spinning under the weight of the
  food — no separate anti-backdrive mechanism needed.
• The container is generic and easy to replace — just reuse a cheap clip-lock storage container.
• Electronics are open-ended — adapt the control circuit to whatever parts you have on hand.
  Need the schematic or wiring details? Comment or DM me.