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Bmp180 – How it works

BMP180 is an integrated circuit by Bosch. When using our board, you are essentially communicating with the onboard BMP180 directly via I2C communication.

BMP180 sensor on board
BMP180 sensor on the board

Datasheet

For an in-depth look at technical specifications, refer to the official BMP180 Datasheet:

BMP180 Datasheet

Detailed technical documentation for the BMP180 sensor


How the sensor works

The BMP180 is a pressure and temperature sensor that can also calculate altitude based on pressure.
The sensor takes measurements by using the piezoresistive effect to gather information.

The piezoresistive effect is a change in the electrical resistivity of a material (e.g., semiconductor, metal) when mechanical strain is applied. The electrical resistance change is due to two causes: a change in geometry and a change in conductivity of the material. The change in resistance is much more pronounced for semiconductors than for metals.

Four Si-resistors are diffused into a semiconductor membrane and connected together to form a Wheatstone bridge. Under the influence of pressure, the diaphragm deforms, thereby affecting the electrical resistance of the four Si-resistors. The change in resistance is proportional to the applied pressure.

Piezoresistor schema
Schematic diagram of the pressure sensor, originally from article [Temperature Compensation Method for Piezoresistive Pressure Sensors Based on Gated Recurrent Unit](https://www.mdpi.com/1424-8220/24/16/5394)

I2C communication

The BMP180 uses the I2C protocol to communicate with a microcontroller. It operates with a fixed I2C address of 0x77 and supports a speed of up to 3.4MHz for rapid data transmission.

Upon request, the sensor responds with pressure values in a 16 to 19 bit format and temperature values in a 16 bit format.