Reminders + Location = Battery Drain?

silverblack

macrumors 68030
Original poster
Nov 27, 2007
2,676
838
In the Siri commercial, there's this really cool part feature the use of Reminders, where a command like "remind me to grab the present when I get home".

Does that mean this switches on the GPS constantly from that point on (i.e., drain your battery constantly)?
 

DougFNJ

macrumors 65816
Jan 22, 2008
1,265
828
NJ
It definitely puts in a drain, but not ridiculously significant, you probably lose an hour or so battery life compared to what you would get in a normal day.
 

Small White Car

macrumors G4
Aug 29, 2006
10,909
1,194
Washington DC
Does that mean this switches on the GPS constantly from that point on (i.e., drain your battery constantly)?
No. 'Location' on an iPhone is really based on several things. It's very unlikely the iPhone would need GPS to know when you're home.

One simple thing is cell towers. It knows where you live and which 3 cell towers it can sense at your house. So it can easily send you the reminder the instant it detects those 3 towers and it'll probably be pretty good guess.

The phone is constantly talking to the towers anyway, so there's not much battery difference for that.

That's how 'Location' works on the iPhone...it uses the simplest method first, and if that fails it goes up the next things...maybe it sees a Wifi network or something. If ALL of those things fail it may eventually turn on the GPS to check, but it's unlikely.

Did you know GPS chips can take several minutes to get a 100% perfect fix? The majority of the time you open Google maps the blue dot is a result of these 'other' methods of location awareness working together to give you a very good guess about where you are. Eventually the GPS kicks in and gives you a perfect location, but there are a lot of other things going on before that point.

Those are the things that Location-based reminders use.
 
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