How to turn your Android phone into a metal detector

Can't find that sharp metal screw you just dropped onto the thick carpet below you? Maybe your Android phone can help.
If you've ever dropped a small screw or a paperclip onto thick carpet, you know how difficult it can be to find them.
With an Android app called Metal Detector (by Smart Tools), you can turn your Android phone into a metal detector. Using the app might just help you find those small metal objects before you accidentally step on them or before they get sucked up into your vacuum cleaner.
Metal Detector works by measuring the magnetic field around the location of your Android phone. It begins with a baseline measurement, then when it detects a metal, the measurement goes up and the color changes from green to red. Unfortunately, it doesn't make a cool, metal detector sound to let you know if you're close.
During our evaluation, it picked up items like paper clips, a Leatherman multitool, and a metal screw. However, it failed to recognize a platinum wedding band, a gold claddagh ring, and a dime -- all the valuable stuff.
You're not likely to find any buried treasure with the app, but it might help you avoid a nail in your foot or a broken vacuum cleaner. If you decide to try Metal Detector, let us know in the comments which items your phone detected and which it didn't.