Smart speakers like Amazon Echo or Google Home have started helping people track their own health, and can even monitor for cardiac arrest. Now researchers at the University of Washington have developed a new smart speaker skill that lets a device use white noise to both soothe sleeping babies and monitor their breathing and movement. With this skill, called BreathJunior, the smart speaker plays white noise and records how the noise is reflected back to detect breathing motions of infants’ tiny chests. When the researchers tested BreathJunior with five babies in a local hospital’s neonatal intensive care unit, it detected respiratory rates that closely matched the rates detected by standard vital sign monitors. White noise is a combination of different sound frequencies, which makes a seemingly random soothing sound that can help cover up other noises that might wake a sleeping baby. To use white noise as a breathing monitor, the team needed to develop a method to detect tiny changes between the white noise a smart speaker plays and the white noise that gets reflected back from the infant’s body into the speaker’s array of microphones. To make things easy for new parents, the team made a system that could run on a smart speaker that replicates the hardware in an Amazon Echo.