Using Llama to limit 3G and conserve battery

Last week I shared some casual findings (n=8) for how much faster my phone’s battery drains when the 3G is on compared to off. If you have an Android, here’s a really easy way to automatically turn your 3G on for a few minutes throughout the day (to sync any new mail, tweets, etc), and then turn off again.

Grab Llama from the Play store (free). Instead of using GPS, it uses the nearby cell tower info your phone is already collecting (or other variables, like day or week or time) to automatically perform custom actions.  I have my Llama set to turn 3G on for 10 minutes at 10a, 1p, and 4p to sync, then turn back off. I’ve been keeping an eye on it the last few days – works great. Here’s the developers’ Instructions page to help anyone interested get rolling.

Llama is fantastic in general because you can set it up to do all kinds of things automatically. Examples:

  • Turn your wi-fi on when you’re home, then turn it off when you leave.
  • Change your phone to vibrate automatically when you arrive at work, then back to ringer when you leave.
  • Set to vibrate instead of ringer automatically when you’re sleeping, then turn back to normal settings at a certain time in the morning.
  • Launch your music player automatically when you plug in headphones.
  • Enable GPS automatically when you plug in a car charger.
  • Require a password to unlock when you’re away out and about, but not when you’re at home.
  • Turn Airplane Mode on when your battery drops below 15%.
  • Automatically start the apps you look at every morning when you wake up at a certain time, like your email, calendar, news, weather, etc.

I haven’t seen anything similar to Llama on the iPhone, and per this Reddit post it sounds like it’s not possible (“iOS apps from the App Store are not allowed to access system settings like that”).