Ultrasound Could Potentially Replace Your Phone’s Proximity Sensor

Phones of the future may not have any proximity sensors, courtesy of Norwegian startup Elliptic Labs. Their plan is to use the speaker on the phone to emit sound at ultrasound frequencies (23kHz-35kHz), while the microphone would listen for distortion. This approach is similar to how bats navigate and hunt, and will be employed to shut off the screen when something is close to it.