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STM develops turnkey sensor for wearables and other IoT devices

Steve Rogerson
December 13, 2016

Swiss chip company ST Microelectronics has developed what it claims is the smallest turnkey sensor board of its type, containing a MEMS accelerometer, gyroscope, magnetometer, pressure sensor and a MEMS microphone. It can be used as a sensing and connectivity hub for developing products such as wearables, gaming accessories, and smart-home or IoT devices.
The SensorTile STM32L4 measures 13.5 by 13.5mm and contains a complete Bluetooth Low-Energy transceiver including a miniature single-chip balun on-board, as well as system interfaces that support use as a sensor-fusion hub or as a platform for firmware development. It can be simply plugged to a host board and when powered it immediately starts streaming inertial, audio and environmental data to STM’s BlueMS smartphone app that can be downloaded free of charge from popular app stores.
Software development is helped by an ecosystem of APIs based on the STM32Cube hardware abstraction layer and middleware components, including the STM32 open development environment.
The system is compatible with the Open Software eXpansion Libraries Open MEMS, Open RF and Open Audio, as well as third-party embedded sensing and voice-processing projects. Example programmes available in source code provide a starting point for evaluation and customisation, including software for position sensing, activity recognition and low-power voice communications.
The complete kit includes a cradle board that carries the SensorTile core system in standalone or hub mode and can be used as a reference design. This compact fully loaded board contains a humidity and temperature sensor, a Micro-SD card socket, as well as a lithium-polymer (LiPo) battery charger. Its simple layout demonstrates how a complete wearable prototype customised with extra functionalities can be designed with the SensorTile core system.
The pack also contains a LiPo rechargeable battery and a plastic case that provides a housing for the cradle, SensorTile and battery combination.
Also part of the kit is a cradle and expansion board with an analogue audio output, a Micro-USB connector and an Arduino-like interface that can be plugged into any STM32 Nucleo board to expand options for system and software development. A programming cable is also included.