How do phones constantly listen for voice commands like ‘Hey Siri’ or ‘Ok Google’ without draining the battery quickly?

Question

How do phones constantly listen for voice commands like ‘Hey Siri’ or ‘Ok Google’ without draining the battery quickly?

In: 255

Answer 1

The big brain of the device does all of the stuff that uses lots of power, like running the display and connecting to the internet. The manufacturers build a little brain in the device who’s only job it is to listen for the phrase. It takes almost no power. When the little brain hears the phrase, it wakes up the big brain