S+ uses a patented bio-motion contact less sensor to monitor your breathing and body movements while you sleep. Extra sensors in S+ detect key sleep-related parameters in your bedroom environment including: sounds, light levels, and temperature. These are analyzed along with how they impact your sleep state to produce customized suggestions for helping you to get a better night's sleep. Simply place the S+ on your nightstand to measure your sleep. S+ works by detecting the movement of your upper body while you sleep.