🌱 Arduino Automatic Watering System for 100 Plants

📦 What This Is

This is a low-cost, scalable automatic watering system using Arduino, designed to control up to 100 plants using a relay-based zone system. Great for gardens, greenhouses, or indoor farms.

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🧰 Components Needed (for ~100 plants)

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🧠 System Overview

You divide your 100 plants into zones (e.g., 5 zones of 20 plants). Each zone is watered by a pump/valve, controlled by a relay. You can:

• Water on a timer

• Water manually

• Water is automatically supplied via moisture sensors

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⚡ Wiring Summary

• Each relay connects to one pump or valve

• Relays are triggered via Arduino’s digital pins

• Use external power for motors (not from Arduino)

• Add diodes across the motors to prevent voltage spikes

• (Optional) Connect moisture sensors to analog pins

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💻 Arduino Code (Timer-Based Example)

const int relayPins[] = {2, 3, 4, 5};  // Up to 4 zones
const int numZones = sizeof(relayPins) / sizeof(relayPins[0]);
const unsigned long wateringDuration = 10000; // 10 sec per zone
const unsigned long intervalBetweenZones = 5000;

void setup() {
  for (int i = 0; i < numZones; i++) {
    pinMode(relayPins[i], OUTPUT);
    digitalWrite(relayPins[i], HIGH); // Relay OFF (active LOW)
  }
}

void loop() {
  for (int i = 0; i < numZones; i++) {
    digitalWrite(relayPins[i], LOW); // Turn ON
    delay(wateringDuration);
    digitalWrite(relayPins[i], HIGH); // Turn OFF
    delay(intervalBetweenZones);
  }
}

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🌧 Optional: Moisture Sensor Automation

Use analog sensors like this:

int moisturePin = A0;  // Sensor analog pin
int relayPin = 2;      // Single zone example

void loop() {
  int moisture = analogRead(moisturePin);
  if (moisture < 500) {
    digitalWrite(relayPin, LOW); // Turn on pump
    delay(5000);
    digitalWrite(relayPin, HIGH);
  }
  delay(10000); // Check every 10s
}

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🧱 Tips for Scaling to 100 Plants

• Group plants based on similar water needs

• Use wider tubing splitters (e.g., 1-to-10)

• Secure tubing so nozzles stay aimed at roots

• Add flow restrictors if some plants get too much

• Upgrade to ESP32 or Raspberry Pi for app/Wi-Fi control

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🧰 Optional Upgrades

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🔌 Safety Tips

• Never power pumps directly from Arduino

• Test the relay logic with the LED before the motors

• Use common ground if using external power

• Secure electronics in waterproof housing

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✅ Final Thoughts

• Easy to build, low maintenance

• Expandable to any number of zones

• You can 3D print pump holders or sensor mounts

• Ideal for school projects, farms, and smart gardens

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🧾 Credits

Created by: Nuwan & (ChatGPT AI)
Year: 2025
You are free to use, remix, and share with credit. 🌿