Abstract: A computing apparatus comprises a processor unit 10 and a foot control unit 13, in addition to a device for presenting information to a user such as a microdisplay. Movement of the foot, which drives operation of a selection element, provides user input to the processor unit. The foot control unit contains a position sensor 27 that detects position relative to a reference unit 26 in the processor unit 10. A stream of relative position data is used to indicate alternative options at the information presentation device. Selection may be carried out by various alternative methods in different embodiments —if the position sensor 27 is also an orientation sensor, this may be by rotation of the foot. This arrangement is particularly suitable for a wearable computing apparatus.