Wearable Sensor Unit Reference Design

STEVAL-WESU1 is a reference design from STMicroelectronics developed and optimized to help designers implement the latest technologies in wearable and portable applications. This reference design includes a complete power management and charging solution. The small form factor of the hardware allows it to be enclosed in a watch strap, so the user can experience a real activity monitoring system and immediately begin appreciating the sensor data acquisition, as well as all of the embedded hardware and firmware features, also thanks to the ST WeSU app available free of charge from Apple Store™ and Google Play™ stores. The Apps are based on BlueST SDK, available on GitHub.

Advanced users can also further reduce the hardware form factor; please refer to STEVAL-WESU1 user manual for more details. Features include: Compact solution for wearable, motion sensing applications with a complete set of firmware examples; iOS and Android apps available; 100 mAh Li-Ion battery included, UN38.3 tested and certified; Micro USB connector for recharging; SWD connector for debugging and programming capability; Watch strap with plastic housing included; Fully tested and certified by FCC (FCC ID: S9N-WESU1) and IC (IC: 8976C-WESU1); and RoHS compliant.

Main components include: STM32L151VEY6 – 32-bit ultra-low-power MCU, LSM6DS3 – 3D accelerometer + 3D gyroscope, LIS3MDL – 3-axis magnetometer, LPS25HB – MEMS pressure sensor, BlueNRG-MS – BLE network processor, BALF-NRG-01D3 - 50 Ω balun with integrated harmonic filter, STNS01 – Li-Ion linear battery charger, and the STC3115 – Fuel gauge IC.

The STEVAL-WESU1 firmware package is built on the STM32Cube software technology so it can easily be augmented with further algorithms. It runs on STM32L151VEY6 and includes the drivers to manage three sensors (LSM6DS3, LIS3MDL and LPS25HB), the Bluetooth low energy network processor (BlueNRG-MS) and the battery management ICs (STC3115 and STNS01). The firmware is freely available on www.st.com.