ESP32 Weather Station Circuit with BME280 and OLED

 

A small weather station is one of the most useful ESP32 projects you can build. With a single sensor and a small display, you can read the temperature, humidity and air pressure in your room or on your balcony without opening an app.

How It Works

The BME280 sensor measures temperature, humidity and pressure, and talks to the ESP32 over I2C. The ESP32 reads those values every few seconds and shows them on a small OLED display, so the latest readings are always visible at a glance.

Components Required

• ESP32 development board
• BME280 temperature, humidity and pressure sensor module
• 0.96 inch OLED display (I2C)
• Breadboard and jumper wires
• USB cable and 5V USB power supply

Circuit Connections

• BME280 SDA to ESP32 GPIO 21, SCL to GPIO 22, VCC to 3.3V, GND to GND.
• OLED SDA to GPIO 21 and SCL to GPIO 22, sharing the same I2C bus, VCC to 3.3V, GND to GND.
• Power the ESP32 from a 5V USB supply; check your board's voltage pins before wiring.

Build Steps

1. Wire the sensor and display as listed, keeping the I2C wires short.
2. Load a program that initialises the BME280 and the OLED, then reads the sensor on a short interval.
3. Show temperature, humidity and pressure on separate lines of the display, with a short label for each value.
4. Test indoors first, then move the unit to a sheltered outdoor spot and compare its readings with a known thermometer.

Troubleshooting

• Display blank: confirm the OLED I2C address in your code and check that SDA and SCL are not swapped.
• Sensor not found: check the BME280 wiring and its I2C address, and make sure it is powered from 3.3V, not 5V.
• Readings frozen: add a short delay between readings and confirm the sensor is not pressed against a warm surface.

Going Further

Once the basic station works, try logging readings to a phone or computer, adding a daily high and low temperature, or building a simple enclosure that keeps rain off the electronics while letting air reach the sensor.

What would you measure first with your own weather station — your room, your balcony, or your greenhouse? Tell us in the comments.

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