SensoMin is a fun free Android app that lets you play theromin type sounds using the g-sensor (accelerometer) built into your phone. Basically you hold your phone flat in the palm of your hand and SensorMin will play a note at a pitch of one kilohertz. Then roll or shake your phone from side to side to change the note pitch, or along its length to change the volume.
You can also change the type of waveform used for the sound, the options being a sine wave (default), a square wave, or a sawtooth wave, all of which give different sounds. To make things more exciting there's also a second sound, the frequency of which can be adjusted using a slider to create harmonics. The slider sets the relationship between the main sound and the harmonic, so if it's set to -50% the harmonic will be half the frequency of the main sound.
Similarly 50% makes the harmonic twice the main frequency and 0% makes both sounds the same frequency. Of course you don't have to use this slider to create harmonic sounds, as you might like to make discordant ones instead, or just use it to create dynamic sound effects. You can also change the harmonic sound waveform (sine, square, sawtooth) separately from the main sounds. That increases the sound effects you can achieve, and even makes the app useful for anyone wanting to learn about sound/signal mixing.
This app also lets you change the g-sensor sampling speed, which allows some fun sound effects to be created. You can also change the maximum volume for the main and harmonic sounds. That's as a percentage of your Android's master volume, so if the app sounds quiet even at 100% volume you can try turning up the volume control on your device. If you have headphones, that may be a better way to experience your sensor theramin (at a sensible, non-deafening, volume of course).
The source code of SensorMin is available for download at www.basic4android.com, but you'll need to be one of their registered developers to do that.
If you like SensoMin, why not take a look at the app store page at www.geocomputing.co.uk.
This app is Copyright 2011 Andrew Thomas. No warranty is provided even of merchantability.
