Digital Technologies/Electronics: Joysticks and Trackballs (1955 – 1970)
Joysticks and Trackballs (1955 – 1970)
To point to objects on radar screens and input track information, increasingly advanced joystick systems were developed by TNO starting in 1955. A joystick is an instrument that converts a mechanical movement of a control stick, slider or rotating ball in the X and Y direction into two proportional analogue electrical voltages via two (or more) potentiometers. These two variable voltages move a symbol across a screen. This information can be used to mark certain information in the image (e.g. a radar echo).
The photos below show the technical and mechanical advancements over time.
Joystick with a mechanical-electrical conversion using two wired resistors (1955)
Joystick with a mechanical-electrical conversion (1955)
Experimental joystick with a mechanical-electrical conversion (1955)
Experimental joystick with a mechanical-electrical conversion using four potentiometers (1956)
Experimental joystick with a mechanical-electrical conversion using two sideways-placed potentiometers (around 1957-1958)
Trackball using a billiard ball (the early 60s) counting stripes on two perpendicular rotating disks
The trackball was built around a billiard ball using integrated circuits and a separate push button (the mid-60s). A chopper disk and a light cell on each of the axles were used to determine the rotation. The electronics use the SN7400 series of Integrated circuits.
Air pump for providing an air bearing of the billiard ball above making it almost frictionless.
Trackball (mid-60s) with the electronics in water-tight enclosures
Prototype of a 5-bit read-out unit for the axis rotation. The five contact strips are visible in the photo. Smaller, later versions of this prototype can be seen above.
