IoT Weather Station with NodeMCU (ESP8266)

Author: Bocaletto Luca

A self-contained weather station that measures temperature, humidity, pressure and ambient light, then serves a live dashboard over Wi-Fi. Perfect for home automation or remote monitoring.

1. Concept

• Sensors
  • DHT22 for temperature & relative humidity
  • BMP280 for barometric pressure & temperature
  • BH1750 for ambient light (lux)
• Controller
  • NodeMCU (ESP8266) runs all sensors on I²C (except DHT22) and hosts a small HTTP server
• Dashboard
  • Web page served by ESP8266, auto-refreshing every 5 s
• Power
  • 5 V USB supply (via micro-USB)

2. Bill of Materials

• 1 × NodeMCU ESP8266 board
• 1 × DHT22 sensor + 4.7 kΩ pull-up resistor
• 1 × BMP280 breakout (I²C)
• 1 × BH1750 breakout (I²C)
• 1 × Breadboard + jumper wires
• 1 × USB cable (for power & programming)

3. Wiring Diagram

     NodeMCU ESP8266
    ┌─────────────────┐
    │           D4 ───┤── DHT22 DATA  
    │           5V ───┤── DHT22 VCC
    │          GND ───┤── DHT22 GND
    │           5V ───┤── BMP280 VCC
    │          GND ───┤── BMP280 GND
    │           D1 ──┐┴─ SCL (I²C)
    │           D2 ──┤─ SDA (I²C)
    └─────────────────┘

• Place 4.7 kΩ between D4 and 5 V for the DHT22 pull-up.
• BMP280 & BH1750 share the same SDA/SCL bus.

4. Software Setup

1. Install Arduino IDE ≥1.8.10 and add ESP8266 board support via Board Manager.
2. In Library Manager, install:
   • DHT sensor library by Adafruit
   • Adafruit BMP280
   • BH1750 by Christopher Laws
3. Create a new sketch named WeatherStation.ino and paste the code below.

5. Usage

• Edit WIFI_SSID and WIFI_PASS to match your network.
• Upload to NodeMCU.
• Open Serial Monitor at 115200 baud to see IP address.
• Browse to http://<ESP_IP>/ on any device.

Enjoy a live, auto-updating weather dashboard on your local network!