Bosch shrinks MEMS altimeters

November 15, 2012 // By R. Colin Johnson
Bosch Sensortec has transferred its portfolio of high-precision automotive MEMS expertise to craft mass-market versions for consumer devices, the latest of which is the world's smallest barometric sensor.

Designed for use as an altimeter smart enough to tell smartphone users what floor they are on in the mall, Bosch's BMP280 measures a tiny 2-by-2.5 millimeters, but gives an accurate reading of altitude to within a resolution of 10 centimeters.

"We were able to shrink the package footprint by over 60 percent, while increasing its temperature stability, resolution and noise-to-power ratio," said Leopold Beer, marketing director at Bosch Sensortec.

Besides smartphones and tablets, MEMS altimeters are finding their way into navigators to measure elevation, sports equipment to measure hill-climb steepness and in health-care devices to measure lung capacity (how "winded" you get from exercise).

Bosch claims its 2-by-2.5-by-.95 millimeter package (right) has a 65 percent smaller footprint than the last generation.

Location based services use altimeters to determine what floor a businesses is on in a building, augmented reality uses altimeters to correctly overlay information on objects to within a resolution of four inches.

Bosch also provides the sensor fusion software required to come up with the reference values that compensate for changes in the local barometric pressure, including from GPS signals, weather stations or web services.

The BMP280 consumes only 2.7-microAmps and can run off power supplies as low as 1.2-V. Both I2C and SPI interfaces are provided.