Abstract: An actuator for a switch, the actuator being movable between on and off positions against an adjustable resilient bias to provide a first signal when said actuator is in said on position and a second signal when said actuator is in said off position.

Abstract: A ball 1 for use in a pointing device 19, the ball 1 having provided thereon a pattern 2 which is of a different optical reflectance to the remainder 6 of the ball, the pattern comprising a line running from a first point 3 on the ball to a second point 4 on the ball 1 along the general line of a spiral 5, said pattern including a plurality of lateral deviations 7 from the general line of the spiral 5 so that a movement of the ball 1 along the general line of the spiral 5 will still provide a detectable change in reflectance.

Abstract: A joystick 50 comprising: a control shaft 52; first and second reflecting surfaces, the surfaces each having a reflectivity that varies along a notional line on the surface; a first sensor assembly 70 comprising a first emitter operable to illuminate the first reflecting surface along said line with radiation, and a first detector arranged to detect radiation emitted by the first emitter and reflected by the first reflecting surface; and a second sensor assembly 72 comprising a second emitter operable to illuminate the second reflecting surface along the line with radiation, and a second detector arranged to detect radiation emitted by the second emitter and reflected by the second reflecting surface; wherein movement of said shaft 52 provides a relative movement between emitters of the first and/or second sensor assemblies 70, 72 and respective associated reflecting surfaces to vary the intensity of radiation reflected, and the detectors of the first and second sensor assemblies are each operable to output a

Abstract: A switch (1) comprising an outer housing (3) and an inner component (5); switch means (13) operable to provide a signal upon depression of said outer housing (3) resilient biasing means (29) located between the inner component and the outer housing to provide a force which bias the outer housing from the inner component; and means (9, 17) for varying the spacing between the inner component and the outer housing and hence the biasing force provided by said resilient biasing means.