ST targets MEMS sensors at activity/fitness apps; adds compass function

January 03, 2017 // By Graham Prophet
STMicroelectronics has assembled a package of motion sensors for “social-fitness” activity-tracking devices, promising additional smart functions, better accuracy, longer battery life, and faster time to market. An enhanced “eCompass” boosts dead-reckoning tracking precision.

Included is an on-board pedometer function to extend battery life in devices hosting always-on activity-tracking apps; the sensors have been designed into several smartphones to enable the social fitness feature “WeRun” inside the “WeChat” messaging app.


These sensors, the LIS2DS12 3-axis “pico” accelerometer, LSM6DSL/M 6-axis inertial module, and the new LSM303AH eCompass help track movement continuously with minimal impact on device battery life by performing various motion-related calculations efficiently on-chip instead of using the main system processor. Pre-embedded algorithms that include high-precision pedometer, step detection, step counting, and significant motion and tilt detection effectively reduce engineering effort and accelerate time to market for applications on devices such as fitness bands, medical monitors, personal navigation and Internet of Things (IoT) nodes, in addition to smartphones and wearable devices.


WeRun is a feature of the WeChat messaging app said to be used by more than 90% of people in China’s largest cities.


The LSM303AH eCompass combines an accelerometer with a magnetic sensor that more than doubles the heading accuracy of other eCompass or pure magnetometer solutions tested at the same geographical latitudes. Combined with the continuous accurate step monitoring, this ensures extremely precise location awareness by dead reckoning where there is no GPS signal, such as in offices, car parks, or shopping malls. ST has engineered software that simplifies user calibration of the temperature drift and the magnetic sensor.


ST’s smart sensors also implement selectable power modes and resolution that help optimize energy efficiency and performance. Additional features that simplify system design include an embedded FIFO, built-in self-test, integrated temperature sensor, and programmable interrupts for conditions such as freefall.


The LIS2DS12, LSM6DSL/M, and LSM303AH smart sensors are in production now. The LSM303AH in a 2 x 2 x 1 mm 12-lead LGA package is priced from $1.63 (1,000).