Adafruit barometric pressure altitude temperature sensors adafruit 2651 the adafruit bmp280 i2c or spi barometric pressure altitude temperature sensors use the next generation bmp280 sensor with an improved accuracy of plusmn1 hpa they use only 2 x gpio pins and provide you with precision air pressure measurements each board contains a 33v regulator an i2c level shifter and pull up resistors on the i2c bus making it 5v ready the boards also support spi which is handy if you wan