Arduino and BMP085

The BMP085 is a barometric and temperature sensor. I’ve got one on a breakout board from geeetech. Using this and an arduino, it is possible to build an electronic barometer.

It can be connected to an arduino uno or nano:

BMP – Arduino
VCC – 3.3V
SCL – A5
SDA – A4

The sketch is originally written by Jim Lindblom at SparkFun Electronics, I updated it slightly to be able to use a more up to date wire library. BMP085.

This will report the temperature and barometric pressure (in Pascal) on the serial port. It is also possible to combine this with a DHT11 (or DHT21 / DHT22) sensor to also get a humidity reading. See The DHT has to be connected to +5 and gnd, signal to port D2 on the arduino. The DHT library can be downloaded from

Arduino nano, DHT11 temperature and humidity sensor,BMP085 temperature and pressure sensor.

Arduino nano, DHT11 temperature and humidity sensor (blue – at top),BMP085 temperature and pressure sensor (red – at bottom).

This work has been done in Arduino 1.0.1 on a debian system.

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