Abstract: A fingerprint verification system for a door includes a digital signal processor (DSP) for being attached to a door, a fingerprint information capturing key and a signal receiving port. Whereby in use, the connector of the fingerprint information capturing key is electrically connected with the signal receiving port. A finger of a user is scanned by the fingerprint information capturing unit for capturing fingerprint information of the user. The captured fingerprint information is transmitted to the DSP through the connector and the signal receiving port for being verified against previous stored fingerprint information. The fingerprint verification system can release a lock of the door or open the door only if they match.

Abstract: A speed detecting device is adapted for use with a direct current motor, and includes a coupling circuit adapted to be connected electrically to a power input line of the motor, a one-shot circuit, a converter circuit, a comparator, and an alarm device. The one-shot circuit is triggered by a current-coupled pulse output, which is generated by the coupling circuit and which corresponds to current flowing through the power input line, and generates a pulse train signal in a form of a series of constant-width pulses, where spacing between adjacent ones of the constant-width pulses varies according to instantaneous operating speed of the motor. The converter circuit receives the pulse train signal, and generates a test signal having a magnitude that varies in accordance with the spacing between the adjacent ones of the constant-width pulses to provide an indication of a detected average operating speed of the motor.