New Contact-Tracing, Social-Distancing Reference Design for Wearables
Suited to bands and bracelets, this scalable solution leverages Bluetooth LE SoC, MEMS accelerometer, and Sub-GHz RF transceiver for accuracy, anti-tampering, remote notifications, and long battery life
STMicroelectronics has announced the availability of a compact and cost-effective reference design ideally suited for monitoring social distancing,
assuring remote operation, provisioning, as well as warning, anti-tampering, and potentially providing contact tracing to protect human health in all environments,
including in response to global or local pandemic conditions.
Leveraging Bluetooth Low Energy technology through its incorporation of ST’s ultra-low-power BlueNRG-2 System-on-Chip with tunable RF output power, the BlueNRG-Tile reference design measures the signal strength of nearby Bluetooth non-connecting beacons and, in real-time, calculates proximity to these sources. The circuit can be provisioned and then operate, issuing warnings when another beacon intrudes on an adjustable perimeter or when tampered with – even when not connected to a smartphone or 5G network.
The base reference design can be supplemented with ST’s S2-LP sub-GHz ultra-low-power RF transceiver to add bi-directional tag-to-cloud communication through the Sigfox “0G” Global Network, allowing private and anonymous tag provisioning, notifications, and an advisory return-channel for emergency warnings. To assure power economy and extend battery lifetime, the ultra-low power components are further enhanced with a MEMS (Micro-Electro-Mechanical Systems) accelerometer that power cycles the unit when it isn’t moving. Optionally, internal or external memory could provide long-term storage of nearby beacons, allowing contact tracing.
Developing this highly-efficient and cost-effective social distancing reference design has significant value in any environment where people need to work safely, said Benedetto Vigna, President Analog, MEMS and Sensors Group, STMicroelectronics. This compact design can be used as is or enhanced for a wide range of applications, including as bracelets and bands or as plugins or add-ons to eyeglasses, helmets, and masks and shields.
Several members of the ST Partner Program have evaluated and adopted the reference design as a foundation for location-monitoring and contact-tracing platforms. These platforms provide a range of capabilities, including proximity alerts and contact recording, using the ST reference design packaged in compact, ultra-low-power tags.
Features of the BlueTile sensor node
- BlueNRG-2: Bluetooth Low Energy single-mode system-on-chip
- BALF-NRG-02D3: ultra-miniature balun and harmonic filter
- LSM6DSO: iNEMO 6DoF inertial module, ultra-low power and high accuracy
- LIS2MDL: magnetic sensor, digital output, 50 gauss magnetic field dynamic range, ultra-low power, high performance, 3-axis magnetometer
- VL53L1X: long range Time-of-Flight sensor based on ST FlightSense technology
- MP34DT05TR-A: MEMS audio sensor omnidirectional digital microphone, 64 dB SNR, -26 dBFS sensitivity, top-port, 122.5 dBSPL AOP
- LPS22HH: ultra-compact piezo-resistive absolute pressure sensor, 260-1260 hPa, digital output barometer, full-mold dust resistant, holed LGA package (HLGA)
- HTS221: capacitive digital sensor for relative humidity and temperature
- CR2032 battery powered
For more information on the BlueTile sensor node, visit the ST website at
STMicroelectronics BlueTile product page
The STMicroelectronics website address is www.st.com.
[Reprinted with kind permission from STMicroelectronics - Release Date 8th June, 2020]