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FabAcademy Documentation: Mint Growing System with Arduino

Introduction

This project aims to create an automated system to grow mint using an Arduino board. The system monitors soil moisture levels and automatically waters the plant when necessary. This allows for efficient and effortless cultivation, ideal for urban gardening enthusiasts or indoor spaces.

Materials Required

Electronics

  • Arduino Uno (or any compatible board)
  • Soil moisture sensor
  • Relay module (to control the pump)
  • Submersible water pump
  • Power supply for the pump
  • Resistors and connection wires
  • Breadboard (prototyping board) or custom PCB

Construction Materials

  • Container for the plant
  • Water reservoir
  • Plastic tubing (for irrigation)
  • Support structure (optional, e.g., made of wood or 3D-printed)

Electrical Diagram

  1. Connect the soil moisture sensor to the analog pins of the Arduino (A0 for data reading, GND and VCC).
  2. Connect the water pump to the relay module, then connect the relay to a digital pin of the Arduino (e.g., D8).
  3. Ensure the pump’s power supply is securely connected via the relay.
  4. Add resistors if necessary to protect the components.

Arduino Code

const int soilSensorPin = A0;
const int relayPin = 8;
const int moistureThreshold = 500; // Adjust according to soil type

void setup() {
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, HIGH); // Turn off the pump at startup
  Serial.begin(9600);
}

void loop() {
  int soilMoisture = analogRead(soilSensorPin);
  Serial.println(soilMoisture);

  if (soilMoisture < moistureThreshold) {
    digitalWrite(relayPin, LOW); // Activate the pump
    delay(5000); // Watering duration (5 seconds)
    digitalWrite(relayPin, HIGH); // Deactivate the pump
  }

  delay(10000); // Wait before the next reading
}

Assembly

System Setup

  • Install the soil moisture sensor in the mint pot.
  • Place the pump in the water reservoir and connect the tubing to the pump outlet.
  • Position the other end of the tubing in the plant pot.
  • Secure all components on a support structure for stability.

Electronics Assembly

  • Follow the electrical diagram to connect the components on a breadboard or solder them onto a custom PCB.

Calibration

  • Test the soil moisture sensor to determine the threshold value to use in the code (e.g., when the soil is dry or moist).
  • Adjust the watering duration based on the plant’s needs.

Testing and Optimization

  1. Test the Sensor: Verify that the values read by the sensor correspond to actual soil moisture levels.
  2. Check the Pump: Ensure it operates correctly and waters evenly.
  3. Optimize the Code: Adjust delays and thresholds to minimize water usage.

Potential Improvements

  • Add a Wi-Fi module (ESP8266) to monitor data remotely.
  • Integrate a light sensor to optimize plant growth.
  • Create a user interface via a mobile app or an LCD screen.
  • Make the system energy-autonomous using solar panels.

Conclusion

This project combines electronics and programming to create a practical and sustainable mint-growing system. Ideal for makers, it provides a foundation for exploring other automated gardening projects.

Simplified system diagram

Happy gardening and happy FabAcademy exploration!