Automatic Feeder optimized for grain

DIY Automatic Rodent Feeder

An automatic feeder designed to dispense grain, seeds, and pellet-style food for small rodents.

While I designed this to specifically fit my need I thought you might get some value from this model. It reliably keeps our six mice well-fed!

Bill of Materials (BOM)

Item	Details / Specifications
DC Gear Motor	5V Micro metal gear motor. I used this one. But I bought it ages ago.
Motor Driver / Controller	Any method to drive/time a 5V DC motor (e.g., ESP32, Arduino, timer relay, or smart plug)
Bottle	~60 mm body diameter with a 40 mm cap
Bearing	683ZZ or similar: 8 mm OD × 3 mm ID (Optional: the model can be modified to run without it)
Fasteners	• Assorted M3 screws • M3 heat-set threaded inserts • 2× M3 set screws (grub screws)

Assembly Steps

1. Prepare the Hopper: Cut a hole through the center of the bottle cap to allow food to flow into the housing.

2. Install Threaded Inserts: Heat-set the M3 threaded inserts into the designated body mounting points.

3. Mount the Motor & Auger:

   • Insert an M3 heat-set insert into the shaft coupling of the auger.

   • Key the motor shaft into the auger and secure it with an M3 set screw (Note: You may need to lightly drill/clean out the shaft hole for a smooth fit).

4. Front Auger Securing: Insert the second M3 heat-set insert and set screw into the front end of the auger.

5. Install Bearing & End Cap: Press-fit the 8 mm bearing into the end cap, slide the auger assembly into the main housing, and fasten the end cap.

6. Attach Bottle: Thread or press the modified bottle assembly into the feed inlet.

Tip for Custom Bottles: If your bottle has different dimensions, you can easily adapt the model in your slicer using standard cylinder boolean cuts/joins or simply edit the raw CAD file.

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To fill the bottle