Magnetic sensor

摘要

A magnetic sensor for discriminating between high and low coercivity magnets is disclosed. The sensor comprises a first magnetic field operable to orient high and low coercivity magnets in a first magnetic orientation. The sensor also comprises a second magnetic field, lower in strength than the first magnetic field, and operable to orient only the low coercivity magnets in a second magnetic orientation opposite to the first magnetic orientation. The sensor further comprises a sensor for ascertaining the magnetic orientation of each of the magnets and thereby identifying if a magnet is a high coercivity magnet or a low coercivity magnet.

主权项

1. A magnetic sensor for discriminating between high and low coercivity magnets, the sensor comprising:
(i) a first magnetic field operable to orient high and low coercivity magnets in a first magnetic orientation; (ii) a second magnetic field, lower in strength than the first magnetic field, and operable to orient only the low coercivity magnets in a second magnetic orientation opposite to the first magnetic orientation; and (iii) a sensor for ascertaining the magnetic orientation of each of the magnets and thereby identifying if a magnet is a high coercivity magnet or a low coercivity magnet and the sensor including a microcontroller for outputting an indication of a magnetic field strength for the magnet and a polarity for the magnet, wherein the sensor further includes pairs of channel detectors, each pair configured to provide a pair of sensing outputs simultaneously to the microcontroller, each pair of sensing outputs includes one positive signal and one negative signal for electrical currents in an analogue format, the microcontroller configured to convert the positive and negative signals to a digital format and subtract the positive and negative signals in the digital format from one another to reduce noise and output a result from the subtraction as the indication in the digital format.