Wifi hero switches wifi on when you are at a known location! I find it a very good app, it means you do not have to leave wifi on all the time it just magically turns on and connects to your known wifi locations! And no battery drain!
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Why would it be a power drain? If you leave WiFi turned on 24/7 (like I do) it doesn't drain fast. I'm only ON WiFi when I'm home - just too lazy to turn it on and off. An app like that could be a very small footprint and should drain much more than the device does already.