IMU saves space, power in hearables

STMicroelectronics has launched the LSM6DSV16BX, a highly integrated sensor that delivers space savings in hearable devices including sports and general-purpose earbuds. The all-in-one motion and bone-conduction sensor combines a six-axis inertial measurement unit (IMU) for head tracking and activity detection with an audio accelerometer for detecting voice through bone conduction in a frequency range that exceeds 1 KHz.

(Source: STMicroelectronics)

The LSM6DSV16BX leverages ST’s Qvar charge-variation detection technology for user-interface controls such as touching and swiping. This makes the IMU suited for applications such as true wireless stereo (TWS) headphones and augmented-, virtual-, and mixed-reality (AR/VR/MR) headsets.

The sensor also uses ST’s Sensor Fusion Low Power (SFLP) technology, specifically designed for head tracking and 3D sound, and the in-the-edge processing resources featured in ST’s third-generation MEMS sensors. These include the finite state machine (FSM) for gesture recognition, the machine-learning core (MLC) for activity recognition and voice detection, and adaptive self-configuration (ASC), which automatically optimizes performance and efficiency. These help to reduce system latency and save overall power, offloading the host processor, said ST.

The processing resources in combination with the high integration is said to reduce system power consumption by up to 70% and PCB area by 45%. It also reduces the number of pin connections by 50%, saving external connections, and shrinks the package by 14% compared with previous ST MEMS inertial sensors.

The LSM6DSV16BX, housed in a 2.5 × 3.0 × 0.74-mm VFLGA package, is available in production and is priced from $3.95 for orders of 1000 pieces. The IMU comes with a variety of software examples, available on ST MEMS GitHub FSM and MLC model zoo. A few examples include pick-up gesture detection to automatically turn on some device’s services, in-ear and out-of-ear detection in TWS headsets and head gestures for 3D sound in headphones. Pre-integrated application examples are available in X-CUBE-MEMS1 package.