Bluetooth LE wearable tags create virtual ‘buffer zone’ for social distancing compliance during Covid-19 pandemic


DigitalAlerts’ Buffr employs Nordic’s nRF51822 SoC to detect when wearers are within 1.5m of one another and trigger alert

Nordic Semiconductor today announces that DigitalAlerts, an Eindhoven, Netherlands-based designer and manufacturer of smart digital warning systems, has selected Nordic’s nRF51822 Bluetooth® Low Energy (Bluetooth LE) System-on-Chip (SoC) to provide the wireless connectivity for its ‘Buffr’ wearable tag. The Buffr device is designed to promote and maintain social distancing in workplaces during the Covid-19 pandemic. 

Wearable buffer zone

Once attached to an individual’s clothing, Buffr creates a virtual ‘buffer zone’ around each wearer to aid compliance with government health and safety guidelines on social distancing. The solution can be used to help reduce the risk of infection from the coronavirus spreading from one person to another—without requiring any investment in infrastructure. 
Nordic’s reliability and broad portfolio of Bluetooth LE SoCs makes the company an ideal partner
Arthur Strijbos, DigitalAlerts
Using the Nordic nRF51822 SoC-enabled Bluetooth LE wireless connectivity, Buffr detects other Buffr wearables by employing Received Signal Strength Indication (RSSI) to determine when the devices come within 1.5 meters of each other. This then triggers an alert in the form of an audible ‘beep’, notifying users they need to maintain greater social distancing.
Through an iOS companion app on a Bluetooth 4.0 (and later) smartphone, devices can be grouped together and programmed as required. For example, Buffr can be programmed to not respond to other nominated devices in the event groups of people are permitted to be within close proximity. Buffr provides between 10 and 14 days of operation between recharge, thanks in part to the ultra low power characteristics of the Nordic SoC. 
Nordic’s nRF51822 SoC is ideally suited for Bluetooth LE and 2.4GHz ultra low power wireless applications. The nRF51822 is built around a 32-bit Arm® Cortex® M0 CPU, 2.4GHz multiprotocol radio, and 256kB/128kB Flash and 32kB/16kB RAM. The SoC is supplied with Nordic’s S130 SoftDevice, a Bluetooth 4.2 qualified concurrent multi-link protocol stack. Nordic’s unique software architecture includes a clear separation between the RF protocol software and DigitalAlerts’ application code. This simplifies development and ensures the SoftDevice doesn’t get corrupted when developing, compiling, testing, and verifying the application code. 

Easy software implementation

“We selected Nordic’s nRF51822 SoC for our Buffr device due to the ease and speed of software implementation enabled by Nordic’s SoftDevice, as well as the availability of the easy-to-use Nordic SDK [Software Development Kit] which was very useful in allowing us to rapidly develop and adjust the firmware,” says Arthur Strijbos, Managing Director at DigitalAlerts. 
“Nordic’s reliability and broad portfolio of Bluetooth LE SoCs makes the company an ideal partner for our Bluetooth LE applications.”