This Automated Fish Feeder Specializes in Accurately Dispensing Tiny Quantities for Little Pets
A screw conveyor allows this Arduino Nano-powered programmable fish-feeder to accurately handle even the smallest food quantities.
Pseudonymous and hard-to-pronounce maker "wjddnjsdnd" has published a guide to building an Arduino Nano-powered fish feeder designed for consistency even when delivering very small amounts of food — using a screw-conveyor system rather than the usual rotational dispenser.
"Commercial automatic fish feeders often struggle with delivering very small and consistent amounts of food — especially for tiny ornamental fish like guppies," wjddnjsdnd explains. "Many feeders rely on rotation-based dispensing mechanisms that vary depending on food size, humidity, or pellet shape. To solve this problem, I designed a micro-dosing automatic fish feeder that uses a screw conveyor mechanism to push out food with far greater consistency. This isn't a new technology, but applying a screw conveyor to a compact home aquarium feeder is something I couldn't find commercially. This design allows stable, repeatable feeding even at extremely small quantities."
The body of the feeder is built from a case of laser-cut acrylic, with 3D-printed parts including the screw conveyor itself — a corkscrew-looking device that pulls material along a tube as it rotates. At the heart of the build is an Arduino Nano microcontroller board connected to a compact 128×64 OLED display and a stepper motor and with two tactile push-button switches acting as a user interface to set the feeding interval without needing to reprogram the microcontroller.
The feeder is attached to the aquarium through a stainless-steel C-clamp, and includes a hinged lid for ease of refilling. A ingenious low-tech solution to the humidity problem — which can cause the food to swell, become sticky, and jam the feeder, not to mention grow mold that is harmful to the fish — is also included: a clothes peg attached to some string and glued to the lid, which acts as a holder for an easily-replaceable sachet of silica gel desiccant.
The full project, including 3D-print and laser-cutting files plus source code, is detailed on Instructables.