POSITION-SENSING SYSTEM

摘要

The invention provides position-sensing means (10) that comprise two potentiometer areas (12, 14) face to face, each said area (12, 14) having a connection (60, 62, 64, 66) at each of two opposite sides able to be used to apply a potential gradient across the area (12, 14), transmission means (18) to enable transmission to each said area (e.g. 14) of a position-indicating signal (20) derived from the other area (e.g. 12) at a position (24) to be sensed, high impedance amplification means (72) and microprocessor means (98) having four ports (741, 761, 781, 801) connected or able to be connected respectively to the four connections (60, 62, 64, 66) and adapted or programmable to switch between a first condition to apply a said gradient across one said area (e.g. 12) and connect the other said area (e.g. 14) to the high impedance amplification means (72) to produce a signal (92) indicative of the potential at said position (24) and hence indicative of a coordinate of said position (24) and a second condition to apply a said gradient across said other area (e.g. 14) and connect said one area (e.g. 12) to the high impedance amplification means (72) to produce a signal (92) indicative of the potential at said position (24) and hence indicative of another coordinate of said position (24). It also provides sensing means (10) that are adapted to be interrogated to indicate a sensed position (24); and/or that comprise means (98, 130, 132, 134, 136, 138, 150, 152) adapted or programmable to adopt a low power consumption condition between interrogations and possibly to detect whether interrogations have failed to occur and consequentially to adopt an even lower power consumption condition; and/or that comprise an element (34) adapted to be positioned by a thumb where each possible position of the positioning element (34) corresponds to a unique position of the thumb. It also provides a system that comprises a devices (196) to be controlled and a plurality of controllers (194) for the device (196) each comprising position-sensing means as above.