Patent ID: 8089459

Claim:
A control device comprising: a base portion disposed at one side of a panel and including a magnet component and a first set of sensors; and a handle portion extending from the base portion to the other side of the panel, the handle portion having less electromagnetic shielding than the base portion, the handle portion including a substantially cylindrical housing and a second set of sensors, the housing disposed around the second set of sensors and having an interior wall radially displaced from the second set of sensors and an exposed exterior wall, the second set of sensors including a magnetoresistive sensor including a magnetoresistive sensor element and a magnet assembly, the magnetoresistive sensor configured to provide an output signal indicative of a twist angle of the handle portion relative to the base portion, so that the first set of sensors and the second set of sensors are disposed on opposite sides of the panel, the housing and one of the magnetoresistive sensor element and the magnet assembly twist as one in accordance with twist of the handle portion, and wherein said output signal comprises two signals each related to the twist angle, a ratio thereof being related to the twist angle and thereby providing a twist angle measurement substantially unaffected by magnetic fields or magnetic materials external to the device.