When the devices are mounted/attached by wristband, clip, pendant/tag/lanyard, or hard hat adapter, all the relevant proximity and location data is sent via Nordic SoC-enabled Bluetooth LE connectivity to a Bluetooth 4.0 (and later) gateway, smartphone, or tablet, from where the user can monitor and review the information, allowing employers to track social distancing practices and identify/log non-compliance. Additionally, the ‘Sentrius™ BT710 Bluetooth Tracker’ iOS and Android app can be used to configure various sensor thresholds including scan settings, alarms, and data logging parameters. Both devices use a high capacity CR2477 battery to achieve approximately six months of operation before replacement, thanks in part to the low power characteristics of the Nordic SoC.
Bluetooth 5.2 support
Nordic’s nRF52833 SoC provides Bluetooth 5.2 support including 2x on-air raw data bandwidth (2Mbps); 4x range; 8x broadcasting ability with advertising extensions that increase the advertising packet payload size to 251 bytes, and an improved Channel Selection Algorithm (CSA #2) compared with Bluetooth 4.2. The nRF52833 SoC’s radio architecture with on-chip PA provides -95dBm RX sensitivity (at 1Mbps in Bluetooth LE mode), a maximum output power of 8dBm, and a total link budget of 103dBm. The radio is capable of Bluetooth Direction Finding functionality and with its large memory can support both receiver and transmitter roles for Angle-of-Attack (AoA) and Angle-of-Departure (AoD) applications.
The nRF52833 SoC combines a 64MHz, 32-bit Arm® Cortex® M4 processor with floating point unit (FPU), with a 2.4GHz multiprotocol radio (supporting Bluetooth 5.2, Bluetooth mesh, Direction Finding, 2Mbps throughput, and Long Range plus Thread, Zigbee, IEEE 802.15.4, and proprietary 2.4GHz RF protocol software). The generous amount of memory (512kB Flash and 128kB RAM) and dynamic multiprotocol support—which enables concurrent wireless protocol connectivity—ensures the nRF52833 is an ideal device for running complex contact tracing applications.
The nRF52833 is supplied with S113 or S140 SoftDevices, Nordic’s Bluetooth RF protocol stacks. The S140 is a qualified Bluetooth 5.1 stack and includes support for 2 Mbps throughput, Long Range, and improved coexistence through CSA #2.
“Nordic’s nRF52833 SoC provides the perfect balance of performance and power consumption, with its combination of Bluetooth radio capabilities and MCU Flash/RAM memory allocation meeting the specific application needs of our Sentrius BT710 and BT720 Bluetooth Trackers,” says Bill Steinike, Vice President of Strategic Business Development at Laird Connectivity. “Nordic’s nRF Connect SDK [Software Development Kit] enabled us to leverage existing Zephyr RTOS development codebases and drivers across multiple product designs to further speed up development cycles and get the products to market even faster, allowing us to meet the urgent demand timing for Covid-19 applications.
“Laird Connectivity has a long-standing relationship with Nordic going back to 2012. We have utilized all generations of Nordic Bluetooth LE solutions in a wide range of modules, end devices, and custom designs. Nordic supports us technically and commercially through the lifecycle of our products.”