Non-intrusive dial rotation detection of high security locks

A rotation detection system for detecting the rotation of a lock dial, the system comprising:

• a rotating lock dial coupled to a lock body by a spindle;
• a magnet for providing a magnetic field, the magnet being disposed in the lock body and coupled to the lock dial for rotation therewith, the magnetic field changing as the magnet moves in response to the rotation of the lock dial;
• a sensor disposed near enough to the magnet to detect the magnetic field and provide a sensor output signal indicative of the magnetic field, the sensor output signal changing as the magnetic field changes;
• a controller coupled to the sensor for receiving the sensor output signal, the controller providing a controller output signal in response to a change in the sensor output signal;
• and
• an alarm interface coupled to the controller for receiving the controller output signal.