[Qt-interest] energy cost of wi-fi scan?

[Chrisian Gagneraud]

On 06/11/11 14:48, franki wrote:
> Hi
>
> I want to know when wi-fi network from my home is available so when I'm
> comming home, my app no phone (Nokia N8) should connect to my home network.
> I'm using QNetworkConfigurationManager and I'm listening for signal
> configurationChanged(QNetworkConfiguration), but phone is scanning wi-fi
> networks quite rarely, so I added QTimer which invokes
> QNetworkConfigurationManager::updateConfigurations every minute.
> It works, I get notifications when wi-fi is available.
> But how quickly my battery will run out??
>
> Another idea is to listen for gps coordinates and then when I'm close to my
> home, I run wi-fi scan until I find home network.
> So the question is: Is retreiving gps coordinates much cheaper (in terms of
> energy) than scanning for wi-fi networks every minute ?
>
> Or maybe other ideas? Basically I want to be notified that wi-fi home network
> is available

If you're using using the location API from QtMobility, you might want 
to use QGeoPositionInfoSource::NonSatellitePositioningMethods, this way 
I think that you will have a position based on GSM base stations, which 
will cost you less energy than using the GPS, you will have less 
accuracy, but that should do the job in your case.

Chris

>
> best regards
> Marek
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-- 
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
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