BMP180 Barometric Pressure Sensor
Barometric pressure and temperature sensor with excellent library support — a weather station staple.
An earlier-generation barometric pressure sensor, still widely used in altimeter and weather-station projects thanks to abundant library support. The BMP180 measures atmospheric pressure and temperature over I2C, and because pressure decreases predictably with altitude, its readings can be converted into a fairly accurate relative-altitude estimate — a long-standing staple for DIY weather stations, altitude-hold drone code, and any project needing a simple 'how high up am I' or 'is the weather changing' reading.
Specifications
| Sensor type | Bosch BMP180 barometric pressure and temperature sensor |
| Operating voltage | 1.8V–3.6V DC (breakout boards regulate from 3.3-5V input) |
| Operating current | ~5 µA at 1 sample/second in standard mode |
| Pressure range | 300 hPa to 1100 hPa (equivalent to roughly 9000m below to 500m above sea level) |
| Pressure resolution | 0.01 hPa in ultra-high-resolution mode (roughly ~0.1m altitude resolution) |
| Temperature accuracy | ±2°C typical |
| Interface | I2C, up to 3.4MHz |
| I2C address | 0x77 (fixed) |
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | VIN | Power, 3.3–5V DC depending on breakout regulator |
| 2 | GND | Ground |
| 3 | SCL | I2C clock line |
| 4 | SDA | I2C data line |
Add standard 4.7kΩ pull-up resistors on SDA/SCL if not already present on the breakout board. Because altitude is calculated from relative pressure, calibrate against a known local sea-level pressure reading (or a recent baseline reading at a known altitude) for meaningful absolute altitude results, since raw pressure alone only gives relative changes.
Variants
For a new project, the BMP280 is generally a better pick than the BMP180 — cheaper, lower power, and supports SPI as well as I2C, with very similar library usage. The BMP180 remains a fine choice if you already have one on hand or are following a tutorial that specifically references it.
| Variant | Temp range | Hum range | Accuracy | Protocol | Price |
|---|---|---|---|---|---|
| BMP180 breakout | ~$2-5 | ||||
| BMP280 | ~$1-3 | ||||
| BME280 | ~$2-5 |