Abstract: Touchless activation of a controlled element, such as a graphic element of a computer display, is provided in any one or more of several dimensions of multi-dimensional coordinate system on the display, in response to the presence of a controlling object, such as a finger, in a predetermined field of free space separate from the element. The field is cyclically optically, angularly scanned in timed relationship with the cyclic generation and counting of timing signals. The scanning causes energy in the field that is reflected from the object to produce triggering signals during each cycle of the scan. The time each triggering signal is received is a function of the angle traversed by the scan from the start of the scan until an object is intercepted. These triggering signals are then used to interrupt the counting of the timing signals, whereby the counted values represent the angles.