Arduino sketches for the STM32WB55-based Katydid (aka Connected Motion Sense) wearable IoT platform
BLE-enabled wearable device for ergonometrics, gait/head/limb/hand tracking, robotics, etc. Intended as an easy-to-use, ultra-low-power IoT platform. Host is the STM32WB55CG MCU in QFN48 package with 1 MByte flash and 256 kB of SRAM with clock speed up to 64 MHz. The platform includes a power on mechanical switch, 1S LiPo battery charger, 16 MByte QSPI flash, BMA400 accelerometer for wake-on-motion, and a secure element for network key storage and authentication.
The 34 mm x 34 mm device is intended to be programmed via USB using the STM32WB55 Arduino core created by Thomas Roell but includes a tag connect for non-USB programming and debugging.
UART, I2C, and SPI ports are exposed at the board edge for expansion.
LIR2450 3.6 V 120 mAH rechargeable coin cell or standard LiPo battery via JST connector.
The platform is an ultra-low-power device with 6 uA sleep current; sleep current due mainly to ~2 uA STBC08 battery charger, ~2 uA QSPI flash, and ~2 uA STM32WB55 MCU.
The basic platform accepts small (12.8 mm x 12.9 mm) modules that can be customized for particular applications. The sketches in this repository demonstrate basic function of the platform as well as several plug-in devices already designed including:
EnviroSense module measuring pressure/temperature/humidity (BME280), eqCO2 and VOC (CCS811), RGBW ambient light intensity (VEML6040) and Human or animal presence (AK9754);
Absolute orientation estimation module (USFSMAX) with heading accuracy of < 0.5 degree rms;
NeuroSense module with 576 Neurons for hardware machine learning.
The 34 mm x 34 mm pcb is designed to mount into a small, inexpensive Hammond 1551P ABS container but the mounting holes are suitable for custom (i.e., 3D-printed) enclosures.
The hardware design is open source and is available in the OSH Park shared space.
Katydid is available on Tindie.
For questions about this project please contact Kris Winer at tleracorp@gmail.com.