Sensor devices support always-on Android apps

By offloading sensor processing to the BHI160 or BHA250, as well as buffering sensor data locally on the devices, system designers can ensure the main application processor is never woken up just to process sensor data. This significantly reduces system power consumption, and thus extends battery life.

The devices integrate a 3- or 6-axis MEMS sensor with the Bosch Sensortec DSP Fuser Core. The BHI160 and BHA250 implement the full Android Lollipop sensor stack and can be updated with new software features to support future releases. The BHI160 is claimed to be the industry’s lowest-power solution that is fully compatible with Lollipop, using less than 1.55mA for a complete 9-axis solution including the Fuser Core, the integrated accelerometer and gyroscope and an external magnetometer.

The Fuser Core is a 32-bit MCU that is optimised to execute Bosch Sensortec’s sensor fusion and activity-recognition algorithms with ultra-low power consumption. The device uses significantly less power than standard MCU, with a saving of up to 95% compared to Cortex M0 and up to 90% compared to Cortex M4 based devices.

The BHI160 integrates a 6-axis IMU, consisting of a 3-axis gyroscope and 3-axis accelerometer, while the BHA250 omits the gyroscope. The BHA250 is, therefore, a smaller and lower-cost device which provides OEMs the flexibility to use it in eCompass applications where a gyroscope is not required.

The BHI160 is available in a 3.0x3.0x0.95mm³ LGA package, while the BHA250 is provided in a 2.2x2.2x0.95mm³ LGA package. These packages are the same size as competitive sensor-only devices without an integrated DSP. Integrating the sensor hub reduces the BOM and saves on valuable PCB space compared to solutions based on standard MCUs.

Both devices are fully pin- and footprint-compatible with Bosch’s sensor-only variants from Bosch Sensortec, giving OEMs the flexibility to support different smart phone devices on one platform, and to make decisions later in the design cycle.

“In modern smart phones, sensors are a key component, and are often switched on all or most of the time for motion-sensitive applications,” said Dr. Stefan Finkbeiner, CEO, Bosch Sensortec. “By handling all sensor data processing, these devices can make a substantial difference to overall battery life.”

Samples are scheduled to be available to selected customers in Q2 2015.