Ultrasonic sound wakes up small devices in IoT networks
A switched off device does not reduce battery life, but is does not work either. Now, an energy-efficient system that is always on alert can turn on devices when needed. This saves energy for applications in IoT network. Researchers from the Arbabian lab at Stanford University have developed an alarm receiver that turns on a device via incoming ultrasonic signals. These work on a significantly smaller wavelength and switch from radio waves to ultrasound. This system detects a wake-up action of 1 nanowatt signal power.