Saturday, May 21, 2016

Google’s Project Soli demo's mmw micro-radar wearable HMI


Google built a tiny radar system into a smartwatch for gesture controls | The Verge
"If you can put something in a smartwatch, you can put it anywhere," Poupyrev says. So ATAP redesigned the Soli chip to make it smaller and draw less power. And then it redesigned it to do the same thing again. And again. Finally, according to Hakim Raja, Soli's lead hardware and production engineer, the team created the tiniest of the chips you see above. It's a tiny sliver you could balance on your pinky toenail, with four antennas that provide full duplex communication for sending and receiving radar pings. The first iteration of Soli, which shipped to in a development kit, drew 1.2w of power. This one draws 0.054w, a 22x reduction.
But making a chip that tiny has drawbacks. Radar was designed to detect massive flying metal objects from miles away, not tiny millimeter movement from your fingers inches away. Until very recently, nobody bothered worrying about the power draw at this scale and nobody had to deal with figuring out what the signal would even look like when it was shrunk down this small.
Jaime Lien is the lead research engineer for Soli, and it's her job to tune the machine learning algorithms which ultimately get hardwired into the chip. Her first realization was that it made sense to convert the spatial signal radar provides into a temporal one that makes more sense on a computer. But that was nothing compared to noise problems you run into at these tiny scales. She showed me the "glitch zoo," a huge set of screenshots of every kind of impenetrable noise that her algorithms have to find signal in. At these scales, it's impossible to do any sort of beam forming and the very electrons running through the chip have to be accounted for.

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