Introduction
Having accurate real-time weather data available at home can be invaluable. Rather than relying on forecasts from the internet or TV, building your own Arduino-based weather station allows you to collect hyperlocal weather data right from your own backyard. In this guide, I'll walk you through all the steps I took to build my own DIY Arduino weather station that provides temperature, humidity, barometric pressure, and rainfall data with unbelievable accuracy.
Parts Needed
To build the weather station, you'll need the following parts:
Arduino Uno
The Arduino Uno is the microcontroller board that will run the weather station program and collect data from the various sensors. The Uno provides analog and digital pins to interface with the sensors, along with USB connectivity to send data to a computer.
Breadboard
A breadboard helps connect the Arduino to the various sensors and modules using jumper wires. The breadboard has rows of connection holes to easily plug components into without soldering.
DHT22 Temperature and Humidity Sensor
The DHT22 sensor provides precise temperature and humidity readings. This digital sensor connects directly to the Arduino with just three pins.
BMP180 Barometric Pressure Sensor
The BMP180 sensor is a high-precision barometric pressure sensor, perfect for measuring air pressure changes to predict weather. It communicates with the Arduino via the I2C interface.
Rain Gauge
A rain gauge funnels rainfall into a measuring cup, with sensors to detect the amount of water collected. This allows the Arduino to read how much rain has fallen over time.
Real Time Clock (RTC) Module
The RTC module keeps accurate time for timestamping weather measurements. The battery-backed clock continues running even when the Arduino board is powered off.
LCD Display
A 16x2 LCD display provides an easy way to view real-time weather data. The screen connects to the Arduino with just a few wires.
Resistors
Resistors help protect the Arduino's pins from too much current draw. I used 220 ohm resistors for the LCD display wiring.
Assembly
With all the parts ready, it's time to assemble the weather station. Follow these steps to put together the circuit on the breadboard and connect the components to the Arduino:
Connect the DHT22
The DHT22 uses a simple 3 pin interface. Connect the +5V pin to the Arduino's 5V supply, the GND pin to ground, and the output pin to Arduino digital pin 2. Place a 4.7K resistor between the data pin and the Arduino pin.
Connect the BMP180
The BMP180 uses the I2C interface, so connect the clock (SCL) and data (SDA) pins to the Arduino's I2C pins - A5 and A4 respectively. Also connect voltage and ground.
Connect the Rain Gauge
The rain gauge has two wires - one for power and one for the signal. Connect +5V to power the sensor and the signal pin to Arduino analog pin A0.
Connect the RTC
The RTC module also uses I2C, so connect SCL and SDA to the same I2C pins as the BMP180. Provide 5V power and ground.
Connect the LCD
There are many LCD pins to wire up! Connect VSS to GND and VDD to 5V. The VO pin goes to a potentiometer and RW to GND. Then connect the Arduino pins 11-13 to D4-D6 and pins 5-8 to D0-D3. Add 220 ohm resistors between each Arduino pin and LCD pin.
Load the Arduino Sketch
With everything wired up, it's time to program the Arduino. I used the Arduino IDE to write a sketch that reads the sensors, processes the data, and outputs it to the LCD. The open-source DHT and LCD libraries made it easy to interface with those components.
The sketch continuously loops through reading the DHT22, BMP180, rain gauge and RTC - storing values like temperature, humidity and rainfall. Every 10 seconds, it outputs a summary of the latest weather data to the LCD. All values get sent over the serial port to the computer so they can be logged.
Constructing the Enclosure
To protect the electronics from the elements, I built an enclosure out of acrylic sheets. This clear case lets me view the LCD readout while keeping moisture and dirt out.
I used acrylic cement to join the pieces into a box. The sensors wire up through holes drilled in the bottom of the enclosure. For the rain gauge, I mounted it high up on a post and ran the wires into the main enclosure below.
Installing Outdoor Sensors
With the enclosure complete, I mounted the DHT22 temperature/humidity sensor, rain gauge and BMP180 barometric sensor outside in an open area. The DHT22 attaches to a mast or wall with cable ties. I secured the rain gauge high up to prevent splashing. And the BMP180 mounts within a small vented box.
Viewing Live Data on a Computer
To view the real-time weather data, I connected the Arduino to my computer via USB. A serial terminal displays the latest temperature, humidity, pressure and rainfall values.
I also wrote a simple Python script that logs the serial output to a CSV file for generating graphs and analyzing trends over time. This can help predict weather based on pressure changes.
Conclusion
Building a DIY Arduino weather station produced an extremely rewarding project that provides hyperlocal weather monitoring right in my own backyard. The accuracy from the high-quality sensors paired with the ease of the Arduino platform made collecting meaningful weather data simpler than I thought possible. This article should help guide anyone through the steps I took to construct the weather station - feel free to reach out if you have any other questions!