A New Contact Tracing Wristband

This week, Accent Systems released a new Bluetooth device that they claim can prevent the further spread of the COVID-19 virus by tracking patients. This device comes as a response to widespread stay-at-home orders to "flatten the curve."

This new tracking wristband from Accent Systems attempts to track only infected persons, specifically ensuring that they remain in isolation when they are contagious, while the rest of the population continues to work. Such a scenario would allow financial markets to recover and hospitals to better cope with a manageable number of cases, plus there would be no need for a mass lockdowns.

The idea is simple: members in a community wear the wristband, which can detect other similar wristbands nearby. If a user gets too close to another user, then the band recognizes its proximity to the other device, records the other user's presence, and submits this data to a health center.

Diagram of how the wristband wirelessly traces contact and reports to the cloud. Image used courtesy of Accent Systems 

Should anyone be diagnosed with the COVID-19 virus, all members of the chain would be alerted to stay at home. At the same time, the authorities would be notified to track the potentially infected individuals to ensure they stay in isolation.

The Hardware

The feasibility of this Bluetooth wristband is realized thanks to Nordic Semiconductor's nRF52832, a low-energy Bluetooth 5.2 SoC. At the heart of the SoC is an Arm Cortex-M4 CPU, which integrates a floating-point unit running at 64 MHz. The SoC has a maximum of 512 KB FLASH and a maximum of 64 KB SRAM and includes all peripherals found on most common microcontrollers, including GPIO, UART, I2C, SPI, band I2S.

The nRF52832. Image used courtesy of Nordic Semiconductor

The nRF52832 supports both 1 Mbps and 2 Mbps Bluetooth low-energy (BLE) modes, has a sensitivity of -96 dBm on LE mode, and programmable output power of +4 dBm to -20 dBm. Other hardware that makes the nRF52832 a prime candidate for such an application includes: 

• the integrated NFC-A tag being potentially useful for contactless payments
• embedded security hardware to ensure compliance with GDPR regulations
• the choice of small SMD packages including QFN48 and WLCSP50

The high-reception sensitivity along with the programmable transmitter power output allows designers to reduce the transmission range of the devices to only see those in close proximity (less than 2 meters) but also helps to increase battery life.

The on-chip DC-DC buck converter helps to not only reduce external component count but also improves power efficiency, which again further increases the battery life of the wristband.

Real-World Application

While the device is newly released, Accent Systems says there are already plans for its adoption in some areas in the Middle East, though the company hasn't disclosed which countries specifically. The Middle East has not been dramatically hit by the virus (unlike others like the US, UK, and Italy), but may see more COVID-19 cases in the next few months.

Accent Systems feels that if the devices can be deployed before mass spreading, it may be the difference between total lockdown and small-scale isolation. The device is also being presented to various law enforcement, armed forces, and healthcare workers to prevent these essential services from being harshly hit. 

The CEO of the company, Jordi Casamada, explains, “With our wristband, if someone tested positive from COVID-19 we can isolate efficiently only those who have had contact with him and who may, therefore, be infected. This wristband would act as a firewall.”

The Issue of Privacy

While the device may be able to prevent some level of spreading, it relies on many (and ideally all) members of a population wearing them. The success of the wearable also relies on the assumption that the virus spreads in a particular manner; it will not be useful for preventing spread in asymptomatic peoples or peoples who don't report their symptoms.

The contact-tracing wristband from Accent Systems. Image used courtesy of Nordic Semiconductor

One area that may ring alarm bells for users is privacy. In the press release for the wristband, Accent Systems assures that "It is a system that does not compromise the security of citizenship, since these are encrypted identifications that only the competent authorities can access (it is GDPR compliant)."

Users should be aware that even though the device is GDPR compliant, their information will need to be decrypted and ran through algorithms for any kind of useful analysis. Under normal circumstances, such a device would be met with skepticism and caution.