My most recent project is an app called woofi.  Let me quote the apps description from its market page:

Simply put, with woofi you define locations like “home”, “work”, or “Joe’s house”, and woofi turns your WiFi radio on when near those points and off when not.

More detailed explanation:

Say, for example, that the only place you connect your phone to WiFi is at home. This means you don’t need for the WiFi radio in your phone to be on when you’re not at home. The rest of the day it’s just sitting there trying to connect to access points and wasting battery.

With this app you would save your “home” location (and wherever else you connect to WiFi regularly…like at the office), and the app would keep track of your location throughout the day and when you weren’t near these saved locations turn your WiFi radio off, and then when you were near them it would turn your WiFi radio back on.

You can, of course, simply turn the WiFi radio on and off manually when you are at-home/not-at-home, the only purpose of this app is to automate doing this for you. I always forget to do this manually…thus the idea for this app.

Most people seem to leave their WiFi on all the time and not realize that it’s on because it just connects to networks that they’ve connected to before automatically.

Here’s what normally happens without this app: Once you’ve connected to your home (or office, or wherever) WiFi, Android will just connect to your home WiFi every time you’re in range. The only way it knows to do this is because the WiFi radio in your phone is on all the time looking for WiFi networks to connect to.

This app replaces that procedure by checking your phones location and leaving the WiFi radio off unless it is needed. Doing this saves battery life.

Coming soon expect some posts about the logic and trade offs made in the development of this app.