Based on "ArduSnake library: Locomotion of modular snake robots" by ObiJuan. (http://www.thingiverse.com/thing:21401) By means of Bluetooth communication, the 4 characteristic parameters of the 2 oscillators, can be modified: amplitude, frequency, phase and offset. With the sign of the phase value, you can change the movement direction: forward or backward. If the oscillators have the same value of phase, movement is not achieved. By varying the offset value (midpoint of the oscillations) the device can move in different directions.