Difference between revisions of "BMP085"

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Latest revision as of 14:49, 3 June 2018

BMP085
Status
Experimental
menuconfig I/O->I2C Master Support->BMP085
Pinning no
Ecmd yes
Control6 no
Depends on ECMD, I2C
Requires -
Code https://github.com/ethersex/ethersex/blob/master/hardware/i2c/master/i2c_bmp085.c

Bosch BMP085 and BMP180 barometric pressure sensors

Sensors

  • Cheap (about 6 EUR)
  • Small
  • Precise (Resolution 0.25m, absolute accuracy +-2.5 hPa)
  • Digital readout via I2C
  • BMP085 and BMP180 are code-compatible, the BMP180 comes in a smaller package

Datasheets

Availibility

Pure sensors

Breakout boards

ECMD

Command Syntax Short description
bmp085 temp Returns the temperature in 0.1°C (16 Bit integer)
bmp085 apress Returns the absolute pressure in Pa (32 Bit integer)
bmp085 height <p0> Returns the height in cm. Needs the pressure p0 at NN as parameter (given in Pa, 32 Bit integer).
bmp085 pressnn <height> Returns the pressure p0 at NN in Pa. Needs the current height in cm (32 Bit integer).

Pressure calculations

  • Pressure calculations for the height and pressnn commands are done using the Barometric formula

Precision

  • The sensor is sensitive to air turbulences (propellers, fans, loud music)
  • The sensor is sensitive to power supply ripple - if not using a battery try to filter it well
  • The results will have some noise, filter them with a moving average or other algorithm to get good results