If you have fish at home and want to find a way to automate feeding, this project might inspire you.

In this tutorial, the author will show how to make your own Arduino-based automated fish feeder so that the little fish won’t go hungry.

The working principle of the automated fish feeder is very simple. We connect the feeding device to the shaft of the stepper motor. When the ultrasonic sensor detects an obstacle, the stepper motor will start, and thus the feeding device will move and dispense food particles into the fish tank.

You can also modify the program to set various parameters, such as the amount of food to be dispensed, etc.

This device can be installed on almost any type of fish tank, and the size of the feeding device can also be enlarged as needed.

Having said so much, let’s start by looking at what materials are needed to make this feeder.

Materials Preparation

• Stepper Motor
• Arduino Uno/Nano
• Stepper Motor Driver
• Ultrasonic Distance Sensor
• Jumper Wires
• Glass Bottle (you can also use a fish tank)
• Cable Ties
• Small Box for Placing Glass Bottle (not needed if using fish tank)
• 3D Printer and PLA Filament
• Arduino IDE

Step 1: 3D Printing

3D print the parts used to dispense food to avoid waste due to overflow.

You can use the STL files provided below. Note that I will not use any padding or supports to print these parts. (Download pack at the end)

The color of the PLA filament can be chosen by you. In my opinion, this color looks nice. You can refer to the images from the previous step to see the printing settings I followed.

This design is made for the 28BYJ-48 stepper motor. Unless you make some modifications to the final design, it cannot be directly applied to other motors.

After printing out the parts, we can start wiring and making the hardware circuit.

Step 2: Circuit Diagram and Program

We can divide the circuit into two parts, the first part is the stepper motor, and the other part is the ultrasonic sensor.

Connect the stepper motor to the driver, and then connect the driver pins to the Arduino according to the instructions below:

• In1 to D2
• In2 to D3
• In3 to D4
• In4 to D5

+ and - pins are connected to the 5V and GND pins of the Uno board respectively.

The ultrasonic sensor has 4 pins: Vcc, Gnd, Trig, and Echo, connected as follows:

• Vcc to 3.3V, Gnd to Gnd
• Trig to D9, Echo to D10

At this point, the circuit part is complete. Now connect the Arduino to the computer via USB.

Open the IDE, use the program below, ensure you select the correct port and board type, then click the upload button. Once done, our hardware circuit part is complete, and we can proceed to the next step. (The code can also be downloaded at the end)

Step 3: Add Stepper Motor Feeder Device

This step is very simple, but also the most important step. First, apply some glue to the stepper motor, then place the 3D printed feeder base on it, press down firmly and hold for a while.

Once the glue is completely dry, we can add the top part with grooves. You may need to apply a little hot glue at the connection to ensure sufficient strength.

Here, you can install the base in the area opposite to the wiring of the stepper motor, which will help when placing the feeder into the fish tank later.

One more thing is to ensure that the gap between the base and the rotating part is very small; otherwise, it may cause food to leak out.

Step 4: Assembly

To make the feeder look more aesthetically pleasing, we use a 3D printed frame to secure the ultrasonic sensor. It is a press-fit design, and I connected it to the HC-SR04, and you can see it looks good now.

To install the stepper motor onto the fish tank, I will use cable ties. Since this fish tank is round, this method is the most suitable. If you are using a square one, I recommend using a clamp-type fixture.

Use enough cable ties to secure it and cut off the excess. For the sensor, I used hot glue to secure it.

Different materials require different fixing methods, so be flexible in choosing the most suitable method for your needs.

Step 5: How to Use

The use of this feeder is not limited to one way; since it is programmable, you can use it in many ways, but now let’s see how I use it.

I will put some rice grains in each of the grooves that need to be dispensed; you can also put fish food in. Once all the grooves are filled with food, ensure there are no obstacles in front of the ultrasonic sensor.

Connect the Arduino to the power supply, and now when you block the sensor with your hand, food will fall into the water, allowing the fish to feed!

This is all about this project; you can modify it according to your needs.