How to Build a DIY Smart Pet Feeder with Arduino

Introduction

A smart pet feeder can be a great way to automate feeding your pet while you are away. With a DIY Arduino-powered pet feeder, you can build your own customizable feeding system at a fraction of the cost of commercial products.

In this article, I will walk through the full process of designing and constructing a DIY smart pet feeder using an Arduino microcontroller. I'll cover:

Choosing the hardware components - the Arduino board, servo motor, sensors, and other parts you'll need.
Design considerations - capacity, power, WiFi connectivity, scheduling features, and more.
Assembling the circuit - connecting all the components to the Arduino.
Programming the Arduino - writing code to control the servo, sensors, and feeds.
Constructing the feeder - 3D printing or building the outer container.
Testing and troubleshooting - making sure your pet feeder works properly.

Follow along below and I'll show you step-by-step how to build your own smart pet feeder that automatically feeds your pet!

Hardware Components

The first step is to gather the electronic components you'll need. Here are the core parts I used for my Arduino pet feeder:

Arduino Uno - The brain of the operation. This microcontroller board will run the code and control the feeder.
Servo motor - To actuate the food dispensing mechanism. A standard hobby servo works great.
HC-SR04 Ultrasonic sensor - Detects when your pet is near the feeder using ultrasonic waves.
DFRobot Gravity IO Expansion Shield - Allows easy connections between the Arduino and components.
5V and 9V power supplies - For powering the Arduino and servo separately.
Wires - For connecting the components together.
RTC module - Real-time clock to keep track of feed times.
Container - To hold the food. A plastic storage container works well.

For optional features like WiFi and remote access, you may also need:

ESP8266 module - For WiFi connectivity and over-the-air (OTA) programming.
IR sensor - To detect when your pet approaches the feeder.
Buttons and LCD - For user input and status display.

Most of these components are available from online retailers like Adafruit, SparkFun, Amazon, or your local electronics shop.

Design Considerations

Before starting the build, think through a few design factors:

Capacity - How much food do you need to hold? Choose a container size accordingly.
Power - The Arduino and servo will need separate power sources - consider battery backup.
Dispensing mechanism - A servo-operated trapdoor is a common approach.
WiFi? - This allows remote access and control via an app. But also adds complexity.
Scheduling - Use the RTC to feed at specific times, like a normal pet feeder.
Sensors - IR proximity or ultrasonic to detect pet and only dispense food when present.
Microcontroller - Arduino Uno is easy to use but any Arduino or similar board will work.
Expandability - Consider a modular design for easy future upgrades.

Start simple, get the basics working, then add more advanced features as you go.

Assembling the Circuit

With the components ready, it's time to assemble the circuit on a breadboard:

Step 1 - Connect the Arduino

Plug the Arduino into the breadboard. Link 5V and GND power rails to the Arduino's 5V and ground pins.

Step 2 - Connect the Servo

Connect the servo's three wires to the Arduino:

Red wire to 5V
Brown wire to GND
Orange (signal) wire to pin 9

Step 3 - Connect the Ultrasonic Sensor

Connect the HC-SR04 sensor:

VCC to 5V
GND to Ground
Trig to pin 12
Echo to pin 13

Step 4 - Connect Other Components

Similarly connect the RTC module, buttons, IR sensor, LCD, and any other components you're using.

Use the IO shield to simplify connecting multiple components. Refer to each part's documentation for specifics on how to wire them.

Double check all connections before powering everything on!

Programming the Arduino

Now for the code to make it work. The Arduino programming happens in two parts:

1. Load Necessary Libraries

At the top of your sketch, load libraries for the RTC, servo, LCD, WiFi module, etc. This makes it easy to control those components.

2. Write Custom Functions

In the main Arduino sketch, write functions to handle different feeder behaviors:

```cpp
// Dispense food
void dispenseFood() {

// Servo code to actuate trapdoor

delay(1000); // Pause to dispense

}

// Check current time
bool isFeedTime() {

// Compare RTC time to feeding schedule

return true or false;

}

// Other functions for proximity sensing, WiFi, LCD, etc.
```

Upload the sketch to the Arduino and it will start running your pet feeder logic!

Constructing the Feeder

Now that the electronics work, you need to build out the physical feeder container and mechanisms:

Step 1 - 3D Print a Container

Design a custom enclosure in CAD, with cutouts for the components. 3D print using ABS or PETG filament.

Or repurpose a plastic storage container, cutting holes with a rotary tool.

Step 2 - Mount Components

Attach the Arduino, servo, and sensors using screws, adhesive, or rubber bands.

Position the ultrasonic sensor to point where your pet will be.

Step 3 - Add Servo-Operated Trapdoor

Cut an opening for the food. Mount the servo with a swinging arm to push open a trapdoor.

Use cardboard, plastic, or metal for the swinging door. Attach to the servo horn.

Step 4 - Final Assembly

Do any last wiring, cable routing, and component mounting. Snap or screw on the lid.

Add a power switch if desired. The feeder hardware is complete!

Testing and Troubleshooting

Before letting your pet use the automated feeder, test it thoroughly:

Make sure the servo smoothly and reliably actuates to release food.
Confirm the sensors are detecting your pet's presence and triggering the feed cycle.
Verify the timing and schedules are working right by watching a few dispense cycles.
Have backup batteries in case of power failure.
Look for loose wires or faulty connections causing erratic behavior.
Check for potential food or water damage to electronics.
Monitor closely at first while your pet gets used to the feeder.

With testing and tweaking, you'll end up with a fully functional Arduino smart pet feeder customized to your needs!

Summary

Building your own DIY pet feeder using an Arduino offers lots of advantages over commercial solutions. With custom programming and construction, you can add features like proximity sensing, remote access, and flexible schedules.

The process involves: choosing components like a servo and ultrasonic sensor, assembling the circuit, writing Arduino code for the feeding logic, constructing the physical container, and testing the full system. With some effort, you can have a smart automated feeder to conveniently care for your pet!