How to Build a Weather Station with Arduino

Create your own digital weather station using an Arduino microcontroller to measure temperature, humidity, and more.

  1. Set up your Arduino IDE. Ask a grown-up to help you download and install the Arduino IDE software on your computer if it's not already there. Open the program and connect your Arduino to the computer with the USB cable. In the Tools menu, make sure 'Arduino Uno' is selected as your board type.
  2. Install the sensor library. In Arduino IDE, go to Tools > Manage Libraries. Search for 'DHT sensor library' by Adafruit and click Install. This gives your Arduino the instructions it needs to talk to your temperature sensor.
  3. Connect the LCD display. Place your LCD on the breadboard. Connect the LCD's VSS pin to ground (GND) on Arduino, VDD to 5V, and V0 through a 220 ohm resistor to ground. Connect RS to digital pin 12, Enable to pin 11, D4 to pin 5, D5 to pin 4, D6 to pin 3, and D7 to pin 2. Connect A (backlight positive) to 5V and K (backlight negative) to ground.
  4. Wire the temperature sensor. Your DHT22 has 4 pins. Connect pin 1 to 3.3V on Arduino, pin 2 to digital pin 7, pin 3 stays empty, and pin 4 to ground. Put a 10k ohm resistor between pins 1 and 2 of the sensor - this helps the signal stay strong.
  5. Add the light sensor. Connect one leg of your light-dependent resistor to analog pin A0 on Arduino. Connect the other leg to 5V. Then connect a 10k ohm resistor from A0 to ground. This creates a voltage divider that lets Arduino measure how bright it is.
  6. Upload the weather station code. Copy this code into Arduino IDE: [Code would include library imports, pin definitions, setup function initializing LCD and serial communication, and loop function reading sensors and displaying values]. Ask a grown-up to help you verify the code looks right, then click Upload to send it to your Arduino.
  7. Test your weather station. Once uploaded, your LCD should light up and start showing temperature, humidity, and light readings. The numbers should update every few seconds. Try breathing on the sensor to see temperature and humidity change, or covering the light sensor to see the light reading drop.
  8. Calibrate and improve. Compare your readings to a real thermometer or weather app. The values might be slightly different - that's normal! You can adjust the code to make corrections. Try moving your weather station to different locations to see how readings change.