An adapter is provided for a motor-driven machine tool which includes a tool driven in an oscillating rotational pendulum motion. A peak in the input signal is compared with a selected signal level to align an output signal relative to a reference signal level. The system extracts different features, including wavelet features andor a disparity map from images captured by image sensors. The thin layer of gel wets both the front surface and back surface of the at least one solar cell and holds the at least one solar cell separate from the base and lid. An engaging position of the first gear wheel with the first rack is different from an engaging position of the second gear wheel with the second rack.