Batteryless rotary encoder

A batteryless rotary encoder, comprising:

• a rotation detecting section, comprising:
• a rotational exciter magnet;
• a piezoelectric transducer, constructed by laminating a magnetic material and a piezoelectric transduction sheet, and the magnet material faces toward the rotational exciter magnet, wherein the rotational exciter magnet attracts or repels the magnet material so that the piezoelectric transducer is pressed or stretched by the magnet material to generate a first output signal when the rotational exciter magnet rotates;
• and
• a transducer, generating a second output signal;
• and
• a signal processing section, comprising;
• a counter, receiving the first output signal and calculating numbers of pulses of the first output signal to indicate revolutions of the rotational exciter magnet;
• and
• a rectifier, receiving the first output signal and generating the power for the counter,
• wherein the transducer is connected to the rectifier and the counter, the counter receives the second output signal to indicate a rotational status of the rotational exciter magnet according to the first output signal and the second output signal.