Smart Irrigation System

An automated plant watering system with remote control via a mobile app.

Hardware

Components

• ESP32 microcontroller - WiFi-enabled board for wireless communication
• DC water pump - Controlled via GPIO pin 23
• 3x DC solenoid valves - Water distribution to individual plants (GPIO 19, 21, 22)
• 3x capacitive soil moisture sensors - Analog readings on GPIO 15, 5, 18
• 3x IRLZ44N MOSFETs - Low-side switching for pump and valves
• 2x 9V batteries - Power supply (connected in series for 18V or parallel for extended runtime)
• LEDs - Visual indicators

Circuit Design

• MOSFETs drive the pump and valves, with ESP32 GPIO pins controlling the gates
• Soil moisture sensors use analog-to-digital conversion (ADC) to measure soil conductivity
• Sensors are calibrated with airValue = 3500 (dry) and waterValue = 1500 (wet), mapped to 0-100% moisture scale

Software

ESP32 Firmware (Mobile_Irigation_No1.ino)

Written in C++ using the Arduino framework.

Key Features:

• WiFi connectivity - Creates or connects to a network using credentials defined in code
• HTTP web server - Listens on port 80 for control commands
• Moisture monitoring - Polls sensors every 20 seconds, converts raw ADC values to percentage
• Valve control logic - Activates specific valves and automatically manages pump state
• RESTful API endpoints:
  • /status - Returns JSON with current moisture levels and valve/pump states
  • /valve1on, /valve1off - Control valve 1 (and similarly for valves 2 and 3)

Operation:

• Pump runs only when at least one valve is open
• When all valves close, the pump automatically shuts off
• Serial output at 115200 baud displays IP address and diagnostic information

Mobile App

Built with .NET MAUI (cross-platform framework) in C#.

Functionality:

• Connects to the ESP32 via HTTP using the IP address displayed in serial monitor
• Displays real-time soil moisture percentages for each plant
• Provides buttons to manually trigger watering for individual plants
• Polls /status endpoint periodically to update UI

Setup

1. Flash the firmware: Upload Mobile_Irigation_No1.ino to the ESP32 using Arduino IDE
2. Note the IP address: Open Serial Monitor (115200 baud) to see the ESP32's IP
3. Configure the app: Update the IP address in the C# code (MAUI app) to match
4. Build and deploy: Compile the MAUI app and install on Android/iOS/Windows
5. Calibrate sensors: Adjust airValue and waterValue in the .ino file based on your sensors' readings in dry soil and water

Notes

• Sensor readings are raw ADC values (0-4095 on ESP32) mapped to percentage
• WiFi reconnection logic attempts to restore connectivity if the connection drops
• The system supports up to 3 plants but can be expanded by adding more pins and endpoints