How to Build a DIY IoT Weather Station with an ESP32 and 0 Other Common Parts

Building your own DIY IoT weather station with an ESP32 microcontroller is a fun electronics project that allows you to create a device that can measure local weather conditions like temperature, humidity, and air pressure. With just a few common components, I was able to build a weather station that sends data wirelessly to the cloud so I can monitor it from anywhere. Here's how I did it.

Selecting the Main Components

The main components I used for this project include:

Assembling the Circuit

With all the parts ready, I first needed to assemble the circuit on a breadboard. This involves wiring up the ESP32 to the BME280 sensor, OLED display, and battery.

The wiring is straightforward. The ESP32, BME280 sensor and display all operate at 3.3V logic levels. The ESP32 has both 3.3V and 5V tolerant GPIO pins which makes wiring easy. I powered the circuit from the 3.3V regulator on the ESP32 to avoid need for a separate 3.3V power supply.

Below is a circuit diagram showing how I connected the components:

With the circuit assembled on the breadboard, it was time to focus on programming the ESP32.

Programming the ESP32

The ESP32 needs to be programmed to interact with the BME280 sensor, display data locally on the OLED, and also connect to Wi-Fi to send data to the cloud.

To program the ESP32, I used Arduino and the ESP32 board support it provides. This allows writing, compiling and uploading code all from the Arduino IDE.

My program initializes communication with the BME280 over I2C to take readings. It shows temperature, humidity and pressure on the OLED. And it connects to my Wi-Fi network to publish sensor data to Adafruit IO, a cloud platform designed specifically for IoT projects.

Below shows a snippet of taking a sensor reading and displaying it:

```c++
bme.takeForcedMeasurement();

float temp = bme.readTemperature();
float humidity = bme.readHumidity();
float pressure = (bme.readPressure() / 100.0F);

display.clearDisplay();
display.setTextSize(1);
display.setCursor(0, 0);

display.print("Temp: ");
display.println(temp);
display.print("Hum: ");
display.println(humidity);
display.print("Pressure: ");
display.println(pressure);

display.display();
```

The full program handles the Wi-Fi connection, cloud integration, and continuously loops through taking readings every 10 seconds.

Assembling the Enclosure

With the electronics complete, I needed an enclosure to protect the project and make it weather proof. I designed and 3D printed an enclosure that everything could fit into.

The enclosure has a slot for the OLED display and openings for air circulation. I also added a breadboard mount to securely hold the electronics inside.

A plastic tube on the side allows running power wires out without affecting water resistance. After assembling all the components into the enclosure, I adhered some rubber sealant on the seam to waterproof it.

Assembled Enclosure

And after some final testing, my DIY IoT weather station was complete!

Viewing the Weather Data

With the station powered and outdoors, it began sending live weather data to my Adafruit IO dashboard. I can monitor the current conditions at any time from my phone.

The dashboard displays nice graphs of temperature, humidity and pressure over time. I can also set alerts on thresholds, for example if temperature drops below freezing.

Having it log to Adafruit IO makes the data available through their API. So next steps could involve sending notifications or automating other systems based on the weather.

Conclusion

Building a DIY IoT weather station with the ESP32 was a really enjoyable electronics project. I learned a lot about working with sensors and microcontrollers. And now I have my own personal weather station providing cool data!

Let me know if you end up making your own ESP32 weather station. I'm happy to provide more details on the steps I followed. This can definitely be expanded by adding additional sensors like wind speed, rain gauge, light levels, etc. The possibilities are endless when you DIY.