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

[franki]

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

best regards
Marek