Motion Sensor Theremin (free)
Render sine, square, triangle, and sawtooth waves. Alter the frequency with the accelerometer, gyros, magnetometer, or by touching the screen
Since an iOS device cannot sense capacitance, the motion sensors and touch screen are used to alter the audio output.
You can assign audio channels to the axes of 4 inputs:
- Touchscreen (x,y)
- Accelerometers (x,y,z)
- Gyrosocopes (x,y,z)
- Magnetometers (x,y,z)
That’s 11 channels total (each axis gets one). A channel has
- Min, max, and current frequencies
- A waveform (sin, square, triangle, sawtoot)
- An effect (such as snapping to closest half note).
- A sensitivity rating (how sensitive is it going to be when you apply force to an accelerometer, or torque to a gyro, etc…)
- Amplitude. To mute a channel, set its amplitude to zero.
And it’s free.