RESONANTLY DRIVEN POWER TOOTHBRUSH HAVING A PRESSURE-SENSING CAPABILITY USING A HALL EFFECT SENSOR

The toothbrush includes a handle portion which includes a power drive system (14) and further includes a brushhead assembly (20), which includes a brushhead arm having a brush element (21) at a distal end thereof A drive train assembly (12) is responsive to a drive signal from the power assembly for converting the action of the power assembly to a motion of the brushhead assembly. A magnet (30) is secured to the rear of the drive train, with a Hall effect sensor (32) mounted within the magnetic field produced by the magnet as the toothbrush moves in operation. Pressure on the brush element produces a phase shift of the Hall sensor output. A processor (15) determines the value of the phase shift of the Hall sensor signal as pressure is applied to the brush member and produces a signal indicative of the pressure applied by using stored information (71) which relates phase shift to pressure for the particular appliance.