Adafruit barometric pressure and temperature sensor i2c adafruit 992 p the adafruit mpl115a2 i2c barometric pressure temperature sensor is a useful low cost sensor for measuring atmospheric pressure with a resolution of 1 5hpa adafruit supply a href https github com adafruit adafruit mpl115a2 a free library and example code a you can download once you have the board wired up and the arduino or other microcontroller programmed it will display temperature pressure and approximate