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 is able to measure the signal strength of nearby Bluetooth non-connecting beacons and, in real-time, calculate 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.
In order 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.
