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.

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

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

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

• 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

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

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

• 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

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

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

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.

• 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

• 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

• 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

• 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 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

{
  "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
}

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

• 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

• 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

• 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

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

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

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

• 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

# Install PlatformIO
pip install platformio

# Navigate to device folder
cd iot-devices

# Upload to ESP32
pio run --target upload

cd iot-backend
npm install
npm run dev

cd iot-dashboard
npm install
npm run dev

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"

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'

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

• 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

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!