MIT’s rather fabulous Computer Science and Artificial Intelligence Laboratory, after using humble WiFi waves to sense movement behind a wall, has now improved its technology to the point that it can remotely detect heart rate and respiration through walls. MIT has successfully used this technology to non-invasively check a sleeping baby’s breathing and pulse, and even to track the breathing of two adults simultaneously. This time last year it was Wi-Vi, but with some further refinements, MIT is now calling it WiZ. While Wi-Vi and other similar technologies could detect movement in general, WiZ can use radio waves to accurately locate up to four people in a room.

Parents could watch their baby’s heart rate from another room without using any kind of wearable device or special sleeping pad with a new development out of MIT that uses Wi-Fi signals to track the rise and fall of peoples’ chests. Researchers at the Computer Science and Artificial Intelligence Laboratory transmitted a low-power wireless signal through a wall and measured how long it took the signals to bounce back. Changes in the reflected signals allowed the team to measure movement, or even minute chest movements. Based on a person’s chest rising and falling, the CSAIL group can determine their heart rate with 99 percent accuracy. The system can track up to four people at a time. “It has traditionally been very difficult to capture such minute motions that occur at the rate of mere millimeters per second,” paper co-author Dina Katabi said in a release. “Being able to do so with a low-cost, accessible technology opens up the possibilities for people to be able to track their vital signs on their own.” The CSAIL team has been perfecting its Wi-Fi tracking for a while now. It has also used radio signals for 3D tracking.