A proximity detector that employs a Hall-effect flux sensor disposed between the like poles of two magnets. The opposing fields of the magnets define a null flux field at a sensing plane of the Hall-effect sensor. A proximate ferrous object will deflect the null point and will therefore apply flux to...http://www.google.fr/patents/US6127821?utm_source=gb-gplus-shareBrevet US6127821 - System for adjusting a magnetic sensor to detect the presence of ferrous objects
System for adjusting a magnetic sensor to detect the presence of ferrous objects
