Need a compass, a flashlight, a voice recorder, or a TV remote? Look no further than your Android phone. We've got 12 apps that ensure it can replace any one of a number of other gadgets
Cohortor.org's gStrings can turn your Android phone into a guitar tuner. Using the microphone, it determines whether a plucked string or a note blown through a mouthpiece has produced the correct wavelength. You can optimise the program for a specific instrument, or you can shift its results to match the tuning practices of a particular orchestra.
The free version should work just fine for most people, but for a euro (85p), you can get gStrings+, which provides more-precise results and - thanks to its relatively compact code - demands less power from your phone's battery.
My wife, a professional musician and music teacher, described gStrings as "clearly a professional tuner for many instruments".
By supplying a regular but adjustable pulse both visually and audibly, a metronome helps musicians keep a steady beat while they practice. You can set the beat to match the piece and your comfort level with it before you start playing. Sophisticated metronomes can accent downbeats to mark the beginning of each measure.
The full version of Zealy Technology's Metronome, which cost $1 (63p) does all of this. The free demo is just that - a demo. You can't even change the tempo on it.
With the real program, you can do that and more. You can set the app to count out anywhere from 40 to 208 beats per minute, and to add a measure-marking ping on the downbeats.
You can play the beat audibly, display it as a blinking series of lights, and receive tactile feedback via vibration. Its vibrating ability means that you can operate this metronome while it's tucked in your pocket.
In fact, by turning off the light and sound, keeping the vibration on, and parking the phone in a pocket, a musician could use it during a performance and no one else would ever know.