Smart Farming IoT System

A comprehensive IoT-based smart farming system featuring ESP32 microcontrollers, environmental monitoring sensors, automated irrigation control, and real-time web dashboard. The system uses MQTT communication via HiveMQ Cloud for real-time data exchange and remote control capabilities.

🏗️ System Architecture

ESP32 (Publisher) → HiveMQ Cloud → Backend (Subscriber) → Supabase PostgreSQL
                ↘               ↗
Frontend (Publisher) → Relay Commands → ESP32 (Subscriber)

Core Components

1. ESP32 IoT Device - Environmental monitoring and actuator control
2. HiveMQ Cloud - MQTT broker for real-time communication
3. Backend API - Data processing and MQTT subscription (Deployed on Northflank)
4. Frontend Dashboard - Real-time monitoring and control interface
5. Supabase PostgreSQL - Database for sensor data and logs

📱 Technology Stack

IoT Device (ESP32)

• Platform: PlatformIO with Arduino Framework
• Microcontroller: ESP32 DevKit v1
• Connectivity: SIM7670C 4G LTE Module
• Protocols: MQTT
• Libraries: PubSubClient, DHT sensor, OneWire, U8g2

Backend API

• Runtime: Node.js with TypeScript
• Framework: Hono
• Database: Supabase PostgreSQL with Prisma ORM
• MQTT Client: Custom implementation for HiveMQ Cloud
• Deployment: Northflank for the MQTT service and Vercel (Serverless) for the REST API
• Authentication: API key-based security

Frontend Dashboard

• Framework: Next.js 14 with App Router
• Language: TypeScript
• Styling: Tailwind CSS with shadcn/ui components
• State Management: TanStack Query (React Query)
• Charts: Recharts for data visualization
• MQTT: Web-based MQTT client for real-time relay control
• Deployment: Vercel

Database & Communication

• Database: Supabase PostgreSQL
• MQTT Broker: HiveMQ Cloud
• ORM: Prisma with TypeScript
• Real-time: MQTT for bidirectional communication

Hardware Components

Main Controller

• ESP32 DevKit: Main microcontroller with WiFi capability
• SIM7670C GSM Module: 4G LTE cellular connectivity for remote monitoring

Sensors

• DHT22/DHT11: Temperature and humidity sensor
• Capacitive Soil Moisture Sensor v1.2: Analog soil moisture detection with corrosion resistance
• Rain Detector: Weather monitoring with digital output
• DS18B20 Soil Temperature Probe: Waterproof soil temperature sensor
• Water Level Sensor: monitoring to prevent dry running

Actuators & Output

• 5V Relay Module: Water pump control switching
• Water Pump: 12V submersible or surface pump
• SSD1306 OLED Display: 128x64 I2C display for essential system status

Communication & Power

• Power Supply Module: Voltage regulation and distribution via breadboard connection
• Breadboard: Prototype connections and signal distribution

Pin Configuration

Component	ESP32 Pin	Connection Type
DHT22 Sensor	GPIO16	Digital
Soil Moisture	GPIO35	Analog
Rain Detector	GPIO18	Digital
Relay Control	GPIO17	Digital Output
Water Pump 12V	Relay	Switched Load
OLED SDA	GPIO21	I2C
OLED SCL	GPIO22	I2C
Soil Temperature (DS18B20)	GPIO23	OneWire
SIM7670C GSM RX	GPIO25	UART
SIM7670C GSM TX	GPIO26	UART
Water Level	GPIO34	Analog
Power Supply Module	Breadboard	VCC/GND Distribution

Wiring Diagram

Complete schematic showing ESP32 connections to sensors (DHT22, soil moisture, rain detector, soil temperature probe), actuators (relay-controlled water pump), display (OLED), SIM7670C GSM module, and power distribution system.

System Features

Environmental Monitoring

• Real-time temperature and humidity measurement
• Soil moisture level tracking with capacitive sensor
• Weather monitoring with rain detection
• Soil temperature profiling with waterproof probe
• Water reservoir level monitoring

Automated Control

• Smart irrigation based on soil moisture thresholds
• Temperature-compensated watering schedules
• Rain detection with automatic irrigation override
• Pump dry-run protection with water level sensing
• Manual override capabilities via web interface

Data & Connectivity

• Local OLED display for essential system status
• 4G LTE communication via SIM7670C for remote installations
• MQTT real-time communication with HiveMQ Cloud
• Cloud database integration with Supabase PostgreSQL
• RESTful API for third-party integrations

User Interface

• Modern responsive web dashboard built with Next.js
• Real-time data visualization with Recharts
• Historical data analysis and trends
• Remote pump control via MQTT commands
• Mobile-friendly interface design
• System alerts and notifications

🔌 MQTT Communication Details

ESP32 Device Communication

// MQTT Topics Used by ESP32
#define SENSOR_TOPIC "sf/esp32-01/sensor"      // Publishes sensor data
#define RELAY_TOPIC "sf/esp32-01/relay"        // Publishes relay status
#define COMMAND_TOPIC "sf/devices/relay/command" // Subscribes to commands
#define STATUS_TOPIC "sf/esp32-01/status"      // Publishes device status

Sensor Data Payload (ESP32 → Backend)

{
  "device_id": "esp32-01",
  "timestamp": "2024-01-15T10:30:00Z",
  "soil_moisture": 65.2,
  "soil_temperature": 22.5,
  "air_temperature": 28.3,
  "humidity": 70.1,
  "rain_detected": false,
  "water_level": 85.0
}

Relay Command Payload (Frontend → ESP32)

{
  "device_id": "esp32-01",
  "command": "toggle_relay",
  "relay_id": 1,
  "state": "on",
  "duration": 300,
  "timestamp": "2024-01-15T10:30:00Z"
}

API Endpoints

Backend REST API

General Endpoints

• GET /api/health - API health check with database connection status
• GET /api/db-test - Database connection test
• GET /api/info - API information and endpoint documentation

Sensor Data Endpoints

• POST /api/sensor-data - Create new sensor data entry
• GET /api/sensor-data - Retrieve sensor data with pagination
• GET /api/sensor-data/latest - Get latest sensor readings
• GET /api/sensor-data/stats - Get sensor data statistics
• GET /api/sensor-data/health - Sensor data service health check
• GET /api/sensor-data/:id - Get specific sensor data by ID
• DELETE /api/sensor-data/cleanup - Cleanup old sensor data records

Relay Log Endpoints

• POST /api/relay-log - Create new relay log entry
• GET /api/relay-log - Retrieve relay logs with pagination
• GET /api/relay-log/latest - Get latest relay log entry
• GET /api/relay-log/status - Get current relay status
• GET /api/relay-log/stats - Get relay operation statistics
• GET /api/relay-log/duration - Get relay operation duration metrics
• GET /api/relay-log/health - Relay log service health check
• POST /api/relay-log/state-change - Log relay state change event
• GET /api/relay-log/:id - Get specific relay log by ID
• DELETE /api/relay-log/cleanup - Cleanup old relay log records

MQTT Endpoints

• GET /api/mqtt/health - MQTT connection status and health
• POST /api/mqtt/publish - Publish message to specific MQTT topic

Real-time Features

• MQTT subscription for live sensor data updates
• WebSocket-like real-time dashboard updates
• Push notifications for critical alerts
• Live relay control with immediate feedback

Project Structure

smart-farming-iot/
├── README.md
├── assets/
│   └── Wiring_ESP32.png
├── iot-backend/           # Node.js Backend API
│   ├── src/
│   │   ├── controllers/   # API route handlers
│   │   ├── services/      # Business logic & MQTT
│   │   ├── repositories/  # Database operations
│   │   ├── routes/        # Express routes
│   │   └── schemas/       # Validation schemas
│   ├── prisma/           # Database schema & migrations
│   └── package.json
├── iot-dashboard/        # Next.js Frontend
│   ├── src/
│   │   ├── app/          # App router pages
│   │   ├── components/   # React components
│   │   ├── hooks/        # Custom React hooks
│   │   └── lib/          # Utilities & API client
│   └── package.json
└── iot-devices/          # ESP32 PlatformIO Project
    ├── src/              # Main application code
    ├── include/          # Header files
    ├── lib/              # Custom libraries
    └── platformio.ini    # Platform configuration

Power Requirements

• ESP32: 3.3V (via onboard regulator from 5V)
• Sensors: 3.3V-5V depending on module
• Relay: 5V control, switched load up to 250V/10A
• Water Pump: 12V DC (via relay switching)
• OLED Display: 3.3V I2C
• SIM7670C GSM: 3.3V-4.2V via power supply module
• Power Supply Module: Breadboard-mounted voltage regulation

Getting Started

ESP32 Setup

# Install PlatformIO
pip install platformio

# Navigate to device folder
cd iot-devices

# Upload to ESP32
pio run --target upload

Backend Setup

cd iot-backend
npm install
npm run dev

Frontend Setup

cd iot-dashboard
npm install
npm run dev

Environment Configuration

Backend Environment Variables (.env)

The backend requires several environment variables for database connection, MQTT configuration, and other settings:

# Supabase Database Configuration
# Connect to Supabase via connection pooling
DATABASE_URL="postgresql://[username]:[password]@[host]:[port]/[database]?pgbouncer=true"
# Direct connection to the database. Used for migrations
DIRECT_URL="postgresql://[username]:[password]@[host]:[port]/[database]"

# MQTT Configuration
MQTT_PORT=8883
MQTT_PROTOCOL="mqtts"
MQTT_HOST="[your-hivemq-cloud-instance].s1.eu.hivemq.cloud"
MQTT_USERNAME="[your-mqtt-username]"
MQTT_PASSWORD="[your-mqtt-password]"
ENABLE_MQTT=1

# MQTT topic subscriptions (comma-separated lists supported)
# Wildcards: + for single level, # for multi-level
MQTT_SENSOR_TOPICS="sf/+/sensor"
MQTT_RELAY_TOPICS="sf/+/relay"

Frontend Environment Variables (.env.local)

The frontend requires configuration for API and MQTT service endpoints:

NEXT_PUBLIC_API_BASE_URL='https://[your-backend-api-url]/api'
NEXT_PUBLIC_MQTT_SERVICE_BASE_URL='https://[your-mqtt-service-url]/api'

ESP32 Device Configuration (config.h)

Create a config.h file in the include directory with the following settings:

#ifndef CONFIG_H
#define CONFIG_H

// WiFi Configuration
#define WIFI_SSID "YourWiFiSSID"
#define WIFI_PASSWORD "YourWiFiPassword"

// MQTT Configuration
#define MQTT_SERVER "ee769d47a04a469da8fe04f0427dfd0b.s1.eu.hivemq.cloud"
#define MQTT_PORT 8883
#define MQTT_USERNAME "smart_farming_iot"
#define MQTT_PASSWORD "YourMQTTPassword"
#define CLIENT_ID "ESP32_SmartFarming_01"

// MQTT Topics
#define SENSOR_TOPIC "sf/esp32-01/sensor"
#define RELAY_TOPIC "sf/esp32-01/relay"
#define COMMAND_TOPIC "sf/devices/relay/command"
#define STATUS_TOPIC "sf/esp32-01/status"

// Pin Configuration
#define DHT_PIN 16
#define SOIL_MOISTURE_PIN 35
#define RAIN_SENSOR_PIN 18
#define RELAY_PIN 17
#define ONE_WIRE_BUS 23
#define WATER_LEVEL_PIN 34

#endif // CONFIG_H

Safety Considerations

• Water pump electrical connections must be properly insulated
• Use GFCI protection for outdoor electrical connections
• Ensure proper grounding of all metal components
• Regular inspection of waterproof seals and connections
• Emergency manual shutoff should be accessible

Closing

This project showcases a complete IoT solution for smart farming, integrating hardware, software, and cloud services. It is designed for scalability and adaptability to various agricultural scenarios. Contributions and improvements are welcome!