Abstract: A cursor control device for personal computers and workstations includes a randomly speckled ball illuminated with diffuse lighting. An image of at least a portion of the illuminated area of the speckled ball is focused by an optical element such as a diffractive optical element onto a photosensitive array. Logic associated with the photosensitive array determines movement of the ball across the array, and translates that movement into conventional cursor control signals supplied to a host system.

Abstract: Methods and devices are disclosed for selectively varying the load to a photodetector such as a phototransistor which forms part of a photosource/photodetector pair and for selectively using to advantage or compensating for the parasitic capacitance of the photodetector to permit reductions in power, conversion of fixed signal thresholds to software controlled digital hysteresis, automatic adjustment and compensation for unmatched photosources and associated photodetectors, and adjustment of fixed voltage thresholds.

Abstract: A positional locating method and apparatus (10) for measuring distances by accurately determining the transit time of ultrasonic wave bursts (22) between two or more points is disclosed. Timer clocks (60), (62), (64) and (66) are started when each of the bursts (22) is triggered to be emitted from a transmission point (14), and are stopped when a highly defined point (56) in the burst (22) is received at a corresponding receiving point (32), (34), (36) and (38). The highly defined point (56) is determined by first analyzing the burst (22) to identify a particular cycle (54) within the burst (22). That particular cycle (54) is then analyzed to detect the specific point (56) within the cycle (54). Use of multiple transmitters (9312), (9314) and (9316) or receivers (932), (934) and (936) permits the dimensions using ordinary trigonometric calculations.

Abstract: An ergonomically designed trackball cursor pointing device in which the cursor movement ball and function switches or buttons are respectively positioned to allow movement of the ball by the thumb while simultaneously operating the switches. More particularly, the switches are placed at the top of the trackball and the ball is placed at the side, to complement the natural placement of the thumb and fingers of the operator thereover.

Abstract: The present invention relates to cursor control devices for computers, and particularly relates to cursor control devices for personal computers which involve the use of a ball rotatable by the fingers for controlling cursor movement.

Abstract: A light ball electronic mouse using a ball with a specific gravity between one and four, X and Y shaft encoders of substantially reduced diameter, and a pressure roller of substantially reduced force for controlling the position of a cursor in a video display.