to control, and a joystick, or a number of wheels or rotary encoders to control fixture attributes such as the orientation (pan and tilt), focus, colour, gobos etc. found in this type of light. Unlike a fader that shows its value based on the position of a slider, a wheel is continuously variable and provides no visual feedback for the value of a particular control. Some form of display such as LCD or LED is therefore vital for displaying this information. The more advanced desks typically have one or more touchscreens, and present a GUI that integrates all the aspects of the lighting. As there is no standard way of controlling an intelligent light, an important function for this type of desk is to consolidate the various ways in which the hundreds of types of intelligent lights are controlled into a single abstract interface for the user. By integrating knowledge of different fixtures and their attributes into the lighting desk software, the detail of how an attribute such as pan or tilt is controlled for one device vs. another can be hidden from the operator. This frees the operator to think in terms of what they want to achieve (e.g. pan 30 degrees clockwise) instead of how it is achieved for any given fixture (e.g. send value 137 down channel 23). Furthermore, should a lighting fixture need to be replaced with one from a different vendor that has different control sequences, no change need be apparent to the control operator. For some further discussion on how intelligent fixtures are controlled, see Digital MultipleX (DMX). Personal computer-based controllers Personal Computer (PC) based controllers are increasing in popularity owing to portability and reduced cost. These lighting console solutions use software with a feature set similar to that found in a hardware-based console. As dimmers, automated fixtures and other standard lighting devices do not generally have current standard computer interfaces, options such as DMX-512 ports and fader/submaster panels connected via USB are commonplace. This system allows a "build-to-fit" approach: the end user initially provides a PC that fits their budget and any other needs with future options to improve the system, for example, by increasing the number of DMX outputs or additional console style panels. Many lightboard vendors offer a PC software version of their consoles. Commercial lighting control software often require a specific, and possibly expensive, hardware DMX interface. However, inexpensive (<$150)