Do you ever forget to feed your fish? Are you constantly rushing out the door, leaving your fishies starving for the whole day? No need to worry anymore! In this project, I make feeding them hassle-free, and works even better with pellets.

I use a proximity sensor to rotate the food cartridges inside the feeder. In addition, a button and LED light is installed when the last rotation is made, so you can refill it with food. Once the button is pressed, the program will automatically reset and the light will turn off. This feeder easily sits above a tank with an optional fin to rest alongside the tank. This simple, durable, and customizable feeder will surely make feeding your fish a breeze, and is open to more advanced modifications to whatever you desire.

Supplies

Circuit Supplies

Arduino RP2040 Connect
180 Servo Motor with pin connector
Button
4 alligator/pin cables
Led bulb
Resistor
ADPDS9960 Proxy sensor
Stemma QT cable
3 pin/pin cables
USB-C charging/data cable
Circuit breadboard

Supplies

Fish Feeder 3D STL file
Laser Cut box 100mm x 100mm x 32mm with rectangle hole on top
Drill
4 command strips
Loctite 414 glue
Electrical tape
Scissors

Step 1: Files for Download

Here are the 3D print files and the code to run the feeder. It is written in CircuitPython, and the model is printed with a Prusa i3.

Run MuEditor and download final_project.py file. Plug in Arduino board to computer and save as code.py to the CircuitPy.
The FishFeeder file is a design built from scratch using TinkerCad.

Step 2: Circuit Assembly

Plug in the cables to the appropriate boards as described in the code file, and connect the pins to the right power and ground locations.
Run the code to see if circuit runs correctly before moving on to the physical assembly.

Step 3: Motor Assembly

To begin the assembly process, the motor blade should be glued in the center of the fan piece using the Loctite glue and reinforced with electrical tape to make sure the blade stays in place.
Next, Attach the motor the blades pointing out, and the motor perpendicular to the blade since the servo only rotates 180 degrees.
Finally, cut a piece of the command strip and remove one side to place on the top of the motor.

Step 4: Box Assembly

Laser cut the box dimensions listed in the supplies section and glue only 3 of the sides in with the cutout rectangle on top as pictured. If the base does not fit in the box, feel free to sand down the sides to allow a nice tight fit.
Attach the other side of the command strip to the top plate so the motor piece sits in the center. Drill a hole on the side to allow the wires to pass thru easily.
Glue the back/sides of the base inside the box, making sure that the motor piece sits on the bottom of the base.

Step 5: Final Assembly

Attach the remaining two command strips to the back of the breadboard. Paste the board to your desired location. I attached mine to the back of the box.
Tape down the proxy sensor, LED bulb, and button with electrical or duct tape. Ensure that all the wiring connections are taped down.
Tape any loose wires together with electrical tape to keep the organized, or hook behind breadboard to avoid dangling wires.

That's it! Now your motion activated fish feeder is ready to go. All you have to do is plug in the board using the USB-C cable to a power outlet or a rechargeable battery and feeding your fish has never been easier.