How to Build a Low-Cost Arduino Weather Station With Temperature, Humidity, and Barometric Pressure Sensors

Introduction

Building your own Arduino-based weather station is a fun and educational project that allows you to measure and track temperature, humidity, and barometric pressure right from your own backyard. With just a few inexpensive components, I can assemble a capable weather monitoring device to better understand my local environment.

In this comprehensive guide, I will walk through the entire process of constructing a low-cost Arduino weather station using common sensors and modules. I will cover component selection, circuit design, code, calibration, and extracting meaningful data from the device. By the end, you will have the knowledge to create your own homemade weather station.

Required Components

To build the weather station, I will need the following components:

• Arduino Uno - The brains of the device. This microcontroller board allows me to program behavior, read sensors, and display data.

• Breadboard - For easily prototyping the circuit connections.

• DHT22 sensor - Provides temperature and humidity measurements.

• BMP280 sensor - Measures barometric pressure and temperature.

• Jumper wires - For making connections between components.

• LCD screen - Displays the sensor measurements.

• 10K potentiometer - Adjusts LCD contrast.

• Resistors - Limit current for LEDs and sensors.

I can purchase these either individually or as part of an Arduino starter kit. The total cost should be around $60 or less.

Step 1: Connect the DHT22 Temperature and Humidity Sensor

The DHT22 sensor provides digital temperature and humidity data. It uses a capacitive humidity sensor and thermistor to measure the surrounding environment.

To hook it up to the Arduino:

• Connect pin 1 (VCC) to 5V.
• Connect pin 2 (DATA) to digital pin 2.
• Connect pin 4 (GND) to ground.

A 10K resistor on the data line helps protect the Arduino from electrical spikes.

Step 2: Add the BMP280 Barometric Pressure Sensor

The BMP280 sensor uses MEMS technology to provide precise pressure and temperature readings.

To integrate this into the circuit:

• Connect pin VIN (voltage in) to 5V.
• Connect pin GND (ground) to Arduino ground.
• Connect pin SCL (clock) to Arduino pin A5 (supports I2C communication).
• Connect pin SDA (data) to Arduino pin A4.

With the sensor wired up, I can start collecting atmospheric pressure data. This is useful for predicting weather changes.

Step 3: Wire Up an LCD Screen

An LCD screen allows me to display the sensor measurements in real time.

To hook it up:

• Pin 1 (VSS) goes to ground.
• Pin 2 (VDD) connects to 5V.
• Pin 3 (VO) gets a 10K potentiometer to control contrast.
• Pin 4 (RS) goes to Arduino digital pin 12.
• Pin 5 (R/W) gets grounded.
• Pin 6 (E) goes to Arduino digital pin 11.
• Pins 7-14 are data lines and require 220 ohm resistors. Connect these to Arduino digital pins 2-9 sequentially.

With everything connected properly, I can display values on the LCD.

Step 4: Upload the Arduino Sketch

Now for the software. The Arduino sketch includes libraries to communicate with the sensors, takes readings periodically, and prints results to the LCD.

Key functions:

• dht.readHumidity() and dht.readTemperature() get DHT22 measurements.
• bmp.readPressure() and bmp.readTemperature() get BMP280 values.
• lcd.print() displays readings on the LCD.
• delay() pauses between samples.

After uploading the code, the weather station springs to life!

Step 5: Mounting and Enclosure

For a polished project, I mount the weather station in an enclosure.

Good mounting ideas:

• Attach to a desktop stand using the Arduino's screw holes.
• Mount on the wall with adhesive pads.
• Place inside a plastic project box.

Ventilation is important so measurements remain accurate.

Positioning the station away from direct sun improves temperature readings. Under an eave or porch roof works great.

Step 6: Calculate Dew Point and Heat Index

With temperature and humidity data, I can calculate additional values like dew point and heat index:

• Dew point indicates the air moisture content. I use a formula that takes the temperature and relative humidity. Higher dew points mean there is more moisture in the air.

• Heat index is how hot the air feels to humans. It incorporates humidity and temperature. The heat index can feel much higher than the true temperature on muggy days.

Adding this functionality requires only minor code tweaks but provides more insightful environmental analysis.

Conclusion

Building an Arduino weather station is a rewarding electronics project that produces meaningful real-world data. With inexpensive parts, free software, and basic coding knowledge, anyone can construct a custom weather monitoring device.

Mounting the station in my backyard allows me to check temperature, humidity, dew point, heat index, and barometric pressure right from home. This hands-on weather forecasting helps me plan my day accordingly.

I hope this guide gives you a solid foundation for creating your own Arduino-based weather station. Customize it to track whatever environmental conditions interest you the most. Before long, you'll have your own automated weather center!