The new reference design uses the Bluetooth Low Energy technology in ST’s ultra-low-power BlueNRG-2 SoC with tunable RF output power. The BlueNRG-Tile reference design measures the signal strength from local Bluetooth non-connecting beacons and calculates the distance to the sources.
The circuit can issue warnings if another beacon intrudes on the adjustable perimeter or if it is tampered with. The circuit works even if it is not connected to a smartphone or 5G network. ST’s S2-LP sub-GHz ultra-low-power RF transceiver can be added to the base reference design to add bi-directional tag-to-cloud communication using the Sigfox “0G” Global Network. This allows private and anonymous tag provisioning, notifications, and an advisory return-channel for emergency warnings.
For power efficiency, and to extend battery lifetime, ultra-low power components are used, including a MEMS accelerometer to power cycle the unit when stationary. Internal or external memory can provide long-term storage of nearby beacons for contact tracing applications.
“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.”
The platform has been evaluated and adopted by several members of the ST Partner Program. The partners have used the solution as a foundation for location-monitoring and contact-tracing platforms.