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.

Along with baby monitoring, the system could also be used in search and rescue scenarios or to track your own health statistics.. The MIT team is now interested in expanding it so it can be used to track emotion, which is also linked to heart rate and breathing.