A couple years ago, a team of researchers from the University of Utah managed to create a wireless network made from standard home automation devices to “see” through walls.
Now, the engineers are using the same technology to monitor breathing in patients with sleep apnea, post surgery, and babies at risk for SIDS. The system consists of a network of 20 off-the-shelf wireless transceivers placed on the edge of a bed, which allows for a total of 380 individual measurements. The transceivers send radio waves across the bed, crisscrossing and intersecting each other at various points on a patient laying on the bed. Chest and abdomen motion impedes the crisscrossing signals, which can be detected and translated into a breathing rate. Measurements were shown to be accurate to two-fifths of a breath per minute and the wireless system performed just as well as measuring the breathing rate with a carbon dioxide monitor connected to a patient with tubes.
The system is intriguing as it’s non-invasive and free of wires. Other devices, such as SIDS monitors, are often connected to infants by wires, electrodes, or belts. Currently, researchers plan on studying whether or not different or multiple radio frequencies detect the breathing rate better than the 2.4 gigahertz frequency currently being used. They also hope to modify the system to be able to detect two people breathing at the same rate, but out of sync.
Article from the University of Utah: Catching a Breath – Wirelessly
Journal Article (PDF): Monitoring Breathing via Signal Strength in Wireless Networks