Ok Google question

[vividrich]

So, why does the phone have to be charging for this to work with the screen off? Curious about the technical reasons....

Posted from my Nexus 7 2013 via Android Central App

 

[crxssi]

So, why does the phone have to be charging for this to work with the screen off? Curious about the technical reasons....

Because it would quickly drain the battery. Think about what you are asking the phone to do:

1) Stay "awake" (even with the screen off)
2) Turn on and keep the microphone on
3) Sample audio continuously
4) Analyze that audio continuously looking for a particular pattern

That is a LOT of stuff. The way the Moto X gets around it is to have a special hardware circuit designed to do ONLY that, so the rest of the OS and phone can continue to sleep. At the moment, no other Android (or non Android) device I know of does that. Will other devices add it eventually? I don't know. Personally I find it kinda creepy.

It is also the reason that unless you find that function/gimmick very useful, you should turn it off on your homescreen/launcher because it will suck a lot of battery there too. And let's face it, if the phone has to be "on" anyway, pressing a single microphone icon is just not that difficult...

 

[indianajonze]

wild guess is because it would be a severe battery drain otherwise. my understanding is the moto x can do this because it has a low energy co-processor dedicated to listening for this command. nexus 5 has no such chip, so the options are to disable it entirely, enable it and watch as your battery drains away or enable it only when charging. clearly option 3 is the way to go...

 

[vividrich]

Ah, makes perfect sense, thanks!

Posted from my Nexus 7 2013 via Android Central App