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IoT Cat Feeder – Building a New "Heart

After a lot of tinkering, wiring, and debugging, I’m now working on creating a **new heart for my automatic cat feeder**. The goal of this build is to replace the old electronics with a more powerful and flexible system based on the **Arduino Uno R4 WiFi** — while also adding a **NEMA stepper motor** for reliable food dispensing and an **HX711 load-cell amplifier** for precise portion control.

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🐾 IoT Cat Feeder – Building a New "Heart"

After a lot of tinkering, wiring, and debugging, I’m now working on creating a new heart for my automatic cat feeder.
The goal of this build is to replace the old electronics with a more powerful and flexible system based on the Arduino Uno R4 WiFi — while also adding a NEMA stepper motor for reliable food dispensing and an HX711 load-cell amplifier for precise portion control.

🔩 Components Used

  • 1× Arduino Uno R4 WiFi – the main controller handling all logic and connectivity
  • 1× NEMA Stepper Motor – drives the feeding mechanism with precision
  • 1× DRV8825 Stepper Motor Driver – provides power and step control to the motor
  • 1× HX711 Load-Cell Amplifier – reads the weight of dispensed food for accurate portions
  • 1× Load Cell – sensor that measures the actual weight of food dispensed
  • 1× Breadboard + Power Supply – for prototyping connections
  • 1× WiFi Dashboard (via Arduino R4) – remote monitoring and manual feeding trigger

🧠 How It Works

  1. The Arduino Uno R4 WiFi acts as the “brain” of the feeder.
  2. Feeding is triggered on schedule or via the web dashboard.
  3. The Arduino sends step commands to the DRV8825 driver, which powers the NEMA stepper motor.
  4. The motor rotates the feeding screw/wheel, dispensing kibble.
  5. The HX711 amplifier + load cell measure how much food was dispensed and report the exact weight back to the Arduino.

This ensures every meal is consistent, precise, and trackable.

📐 Circuit Design

1. PCB / Schematic Diagram

PCB Diagram

The schematic shows how the system is wired:

  • Arduino UNO R4 WiFi provides control logic and WiFi connection.
  • DRV8825 driver connects between the Arduino and NEMA motor.
  • HX711 amplifier interfaces with the load cell and sends calibrated weight readings to the Arduino.
  • Power supply ensures stable current for both logic and motor.

2. Wiring / Breadboard Diagram

  • The Arduino R4 connects to the DRV8825 with step, direction, and enable pins.
  • The DRV8825 outputs motor current to the NEMA motor.
  • The HX711 connects to the load cell and transmits precise food weight back to the Arduino.
  • A separate DC power source ensures the motor runs reliably without overloading the Arduino.

💻 Web Interface

The Arduino R4 WiFi enables a lightweight web interface:

  • Trigger feeding remotely
  • Monitor meal weight in real-time
  • Adjust motor steps per portion
  • Log feeding history

✅ Conclusion

With the Arduino Uno R4 WiFi, DRV8825, NEMA stepper motor, and HX711 load-cell amplifier, the cat feeder now has a brand new “heart”.
It dispenses food with accuracy, monitors meal weight, and can be fully controlled over WiFi.

This upgrade makes the feeder more reliable, precise, and connected — ensuring my cat never misses a properly measured meal. 🐱⚙️