Over the summer, EDN Aspencore published a series of articles on how the electronics industry has responded to the COVID pandemic. In term, I’m doing a series of blog posts summarizing these articles. In my first post, I discussed Majeed Ahmad brief, which offered a “sneak peek into the brand-new design ecosystem built around the fight against the coronavirus pandemic.” My next post covered the articles on the use of Bluetooth technology, especially as used in bracelets. In this piece, I’ll focus on the articles that addressed technologies – ultrasonic sensors and SDK’s – used for social distancing and contact tracing.
In Ultrasonic for Social Distancing Tags, Junko Yoshida argues that this technology “might just be the wireless technology best suited to enabling contact tracing and social distancing.” The need to get employees back to work is heightening demand for “for apps and wearable devices that can alert workers when they violate social distancing precautions and come too close to one another…[and that can] keep track of which workers have come into close contact with whom, when and for how long.”
There are a number of different embedded devices under consideration: bracelets, clips on lanyards, badges, the ubiquitous smartphone – and there are a number of wireless approaches in contention. One of these is ultrasonic sensors used in tag solutions.
For measuring social distance, accuracy is the prime attribute. Ultrasound can provide accuracy at less than 1 cm, which is vastly superior to the other wireless technologies out there, including Bluetooth Low Energy (BLE). Privacy (or lack thereof) is another perceived weakness when it comes to BLE.
Proponents of ultrasound also argue that it’s preferable to ultra-wideband (UWB) when it comes to footprint – UWB requires an antenna – and power consumption. They also claim that, when it comes to false positives, ultrasound is a better choice.
Overall, this article is an interesting look at the different devices and wireless technologies that will help the workforce safely back to work. (It’s worth noting that the strong arguments made for ultrasound came from an ultrasound company.)
SDKs finetune BLE SoCs for contact-tracing, social-distancing designs by Majeed Ahmad, writes that:
While Bluetooth Low Energy (BLE) solutions are finding a way into a variety of products to help slow the spread of COVID-19, the current technology for distance measurement and positioning—received signal strength indicator (RSSI) technology—is based on measuring the strength or power of the received radio signal. However, that is inherently flawed due to the sensitivity of objects in the radio path blocking or reflecting the radio signals.
Software can find a way around this, with SDKs that can take care of the distance measurement issues. A couple of different companies offer SDKs for their BLE SoCs. Dialog Semiconductor’s SDK enables their chips to “chips to interleave BLE data packets with constant tone frequency exchanges, which in turn, allows the on-chip 2.4 GHz radio to generate the signals needed for phase-based ranging.” This improves their BLE chip’s accuracy for distance measurement and makes them contact-tracing ready.
STMicroelectronics offers a reference design built around their Bluetooth SOC. The reference design “enables engineers to implement private and anonymous tag provisioning and notifications in devices such as bands and bracelets in outdoor or closed professional environments like factories, offices, and medical facilities.”
Good to know that there’s so much work going on to make it possible for companies to ensure the safety of their workers.