Wi-Fi Signal Tracks Heartbeat Without Wearables

Summary

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.Wi-Fi signals today primarily transmit data. But these signals can also be used for other innovative purposes. For instance, one California-based team has proposed using ambient Wi-Fi signals to monitor a person’s heart rate. The new approach, called Pulse-Fi, offers advantages over existing heart-rate-monitoring methods. It’s low-cost and easily deployable, and it sidesteps the need for people to strap a device to their body. Katia Obraczka is a professor at the University of California, Santa Cruz, who led the development of Pulse-Fi. She notes that continuous tracking of vital signs, including heat rate, can help flag health concerns such as stress, dehydration, cardiac disease, and other illnesses. “But using wearables to monitor vitals can be uncomfortable, have weak adherence, and have limited accessibility due to cost,” she says. Camera-based methods are one option for remote, contactless tracking of a person’s heart rate without a wearable device. However, these approaches may be compromised in poor lighting conditions and may also raise privacy concerns.In the search for a better option, Obraczka, along with postdoc student Nayan Sanjay Bhatia and high-school intern Pranay Kocheta working in her lab, sought to create Pulse-Fi. “Pulse-Fi uses ordinary Wi-Fi signals to monitor your heartbeat without touching you. It captures tiny changes in the Wi-Fi signal waves caused by heartbeats,” says Obraczka.How Can Wi-Fi Signals Measure Someone’s Pulse? Specifically, the team designed Pulse-Fi to filter out background noise and detect the changes in signal amplitude brought about by heartbeats. They developed an AI model—capable of running on a simple computing device, such as a Raspberry Pi—which then reads the filtered signals and estimates heart rate in real time. The team tested their approach in two different experiments, which are described in a study published in Au...