Pressure Sensor
What is a BMP280/BME280 Sensor?
BMP280 and BME280 modules measure barometric pressure for weather stations, altitude estimation, drones, IoT dashboards, and environmental logging. They are widely searched because they combine useful data with simple I2C wiring.
BMP280 measures pressure and temperature. BME280 adds humidity, making it a stronger choice for complete weather projects when the small price difference is acceptable.
Key Features
Weather Station Core
Tracks pressure trends that help infer changing weather conditions.
Altitude Estimation
Converts pressure changes into approximate altitude for drones and portable instruments.
I2C or SPI Interface
Most breakout boards work over I2C with only SDA and SCL pins.
High Resolution
Sensitive enough to observe small pressure changes when configured correctly.
Low Power
Works well in battery weather nodes and ESP32 deep-sleep logging projects.
Temperature Compensation
Includes temperature data used internally to improve pressure readings.
Pin Configuration
VIN / VCC
Power input. Many breakouts accept 3.3V and some accept 5V through a regulator. Check your board.
GND
Ground reference shared with the microcontroller.
SDA
I2C data line. Connect to Arduino A4 on Uno or the configured SDA pin on ESP32.
SCL
I2C clock line. Connect to Arduino A5 on Uno or the configured SCL pin on ESP32.
CSB / SDO
Optional address or SPI pins on some modules. Leave in default I2C configuration unless needed.
How It Works
The Science Behind It
A MEMS pressure sensor contains a tiny diaphragm that flexes as air pressure changes. On-chip circuitry measures that mechanical change and converts it into a digital pressure value.
Altitude estimation uses the fact that air pressure decreases as elevation increases. Weather changes also affect pressure, so absolute altitude needs local sea-level pressure calibration.
Altitude Estimate:
Pressure trend down = possible rising altitude or weather shift
Altitude m ≈ 44330 x (1 - (P / P0)^0.1903)
P0 = local sea-level pressure reference
For weather stations, pressure trend is often more useful than a single raw pressure number.
Wiring Tips & Best Practices
Use Correct Logic Voltage
Bare sensors are 3.3V devices. Use breakout boards with regulators/level shifting for 5V Arduino when needed.
Scan I2C Address
BMP280/BME280 modules commonly use 0x76 or 0x77, depending on the SDO pin state.
Avoid Airflow Bursts
Direct fan airflow or enclosure pressure can cause noisy readings.
Average Samples
Use oversampling and filtering in the library for smoother altitude and weather data.
Set Sea-Level Pressure
Calibrate P0 from local weather data if you want useful altitude estimates.
Choose BME280 for Weather
Use BME280 when you also need humidity; use BMP280 when pressure is enough.