Smart Fish Feeder (ESP32 + MQTT)

An automated aquarium feeder system based on the ESP32. It dispenses food via a motor pulse triggered by Home Assistant and continuously monitors tank temperature.

⚡ Features

• Remote Feeding: Trigger a measured feed pulse via MQTT (tank/feed).
• Temperature Monitoring: Reports water temp every 10 seconds via MQTT (tank/temperature).
• Home Assistant Integration: Fully compatible with HA Dashboards and Automation.
• Safe Power Design: Optically isolated power rails (ESP32 vs Motor) to prevent brownouts.

🛠 Hardware List

• Microcontroller: ESP32-D0WD-V3 (DevKitC)
• Actuator: DC Motor (3V-6V) with auger/screw mechanism
• Switching: N-Channel MOSFET (IRFZ44N)
• Sensor: DS18B20 Waterproof Temperature Sensor
• Protection:
  • 1N5822 Schottky Diode (Flyback protection)
  • 10kΩ Pull-down Resistor (Gate to GND)
• Power:
  • USB-C (5V) for ESP32
  • External 5V/12V DC Adapter for Motor

🔌 Wiring & Pinout

⚠️ CRITICAL: The ESP32 and Motor Power Supply must share a Common Ground, but 5V lines should remain separate to prevent noise/brownouts.

GPIO Config

Component	Pin	ESP32 GPIO	Notes
MOSFET Gate	Left Leg	GPIO 27	Use 10kΩ Pull-down to GND
Temp Data	Yellow Wire	GPIO 14	Requires 4.7kΩ Pull-up (if not on module)

Circuit Diagram (MOSFET)

• Gate (Left): -> GPIO 27
• Drain (Middle): -> Motor Negative (-)
• Source (Right): -> Common GND
• Motor (+): -> External Power 5V
• Diode: Across Motor Terminals (Silver stripe to +5V)

💻 Firmware Configuration

Dependencies (Arduino IDE):

• PubSubClient (Nick O'Leary)
• OneWire
• DallasTemperature

Setup:

1. Update ssid, pass, and mqtt_server in fish_feeder.ino.
2. Set MOTOR_PIN (Default: 27) and TEMP_PIN (Default: 14).
3. Upload.

🏠 Home Assistant Integration

1. Manual Configuration (YAML)

Add to configuration.yaml to create entities:

mqtt:
  sensor:
    - name: "Fish Tank Temperature"
      state_topic: "tank/temperature"
      unit_of_measurement: "°C"
      device_class: temperature
      unique_id: "fishtank_temp_01"

  button:
    - name: "Feed Fish"
      command_topic: "tank/feed"
      payload_press: "pulse"
      icon: mdi:fish
      unique_id: "fishtank_feed_btn"

2. Dashboard (Lovelace)

• Temperature: Use a Gauge card linked to sensor.fish_tank_temperature.
• Feeder: