For this project, I hooked up an accelerometer to the Arduino to monitor the x, y, and z-directions. The bottom half of the sensor values were ignored, so that subtle movements would not be recorded, only extreme movements. Each direction of movement has a designated oscillator at a fixed, unique frequency, and the oscillator was applied over a short attack time, giving the instrument its characteristic "bell" sound.
The purpose of this instrument was to emulate a set of bells, both in terms of sound/timbre and inflexibility, i.e. the inability to change the frequency of the bell.