Indian American helps develop wake-up receiver for smart devices

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Amin Arbabian, assistant professor of electrical engineering, right, and graduate student Angad Rekhi demonstrate their ultrasonic wake-up receiver and the circuit boards used to test its performance. (Image credit: Arbabian Lab)

NEW YORK – Have you ever turned off your phone due to low battery and end up missing a number of phone calls messages and alarms?

Well, not to worry, because Angad Rekhi, an Indian American graduate student at Stanford University and his partner Amin Arbabian, an assistant professor of electrical engineering at Stanford University, have developed a wake-up receiver for smart phone, according to a press release.

Rekhi and Arbabian’s wake-up receiver allows a device that is shut off, to turn on in response to incoming ultrasonic signals which are inaudible to the human ear unlike radio waves.

“By working at a significantly smaller wavelength and switching from radio waves to ultrasound, this receiver is much smaller than similar wake-up receivers that respond to radio signals, while operating at extremely low power and with extended range,” the press release states.

This wake-up receiver also gives smart devices the ability to communicate directly with one another without human intervention.

“As technology advances, people use it for applications that you could never have thought of. The internet and the cellphone are two great examples of that. I’m excited to see how people will use wake-up receivers to enable the next generation of the Internet of Things,” said Rekhi.

According to the press release here is how it works: “Once attached to a device, a wake-up receiver listens for a unique ultrasonic pattern that tells it when to turn the device on. It needs only a very small amount of power to maintain this constant listening, so it still saves energy overall while extending the battery life of the larger device.”

A well-designed wake-up receiver will also allow a device to be turned on from a significant distance however, designing these devices can be challenging.

“Scaling down wake-up receivers in size and power consumption while maintaining or extending range is a fundamental challenge, but this challenge is worth pursuing, because solving this problem can enable scalable networks of wake-up receivers working in our everyday environment,” Arbabian said, adding that in order to miniaturize the wake-up receiver and drive down the amount of power it consumes, Rekhi and him had to make use of the highly sensitive ultrasonic transducers which converted the analog sound input into electrical signals and were provided by the Khuri-Yakub lab at Stanford.

Though the ultrasound wake-up receiver requires a battery, it still has a much greater range than the wirelessly powered devices as it maintains a long lifetime due to an extremely low power draw.

The press release suggests that wireless power and wake-up receivers although serve different purposes, will hint at a turning point in devices that make up the internet of things.

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