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Technical overviewThe goal is to control house-voltage (as well as low-voltage) Christmas lights with a low-voltage signal that is generated by a central computer that runs the show and the music.The show is run by a Windows XP (patooie!) personal computer, under an application called Vixen, which is used both to develop the show and to run it and play the music (which in turn drives the FM transmitter). A dongle attached to the computer’s USB port converts the output of Vixen to DMX-512, a standards-based light control environment originally developed for the entertainment industry, specifically rock concerts. The DMX signal is split into three main legs – each feeds three DMX-based house-voltage light controllers and one of those legs is extended to a controller that runs at 12-volts DC . Each house-voltage controller handles four channels of DMX and common household outlets are driven by each of those channels. The DMX controller has a microprocessor that turns the DMX signal into electrical pulses that drive optocouplers, which in turn drive triacs. Each triac controls one AC electrical circuit. Up to three strings of 100 common Christmast mini-lights is thus controlled. The low-voltage controller (MR16) handles the DMX signal in much the same way as the electrical-box controller above, except that everything operates at 12-volts DC, which can be used to drive LEDs that are wired in series/parallel combination circuits on the frames on the bannisters. Much of the 2009 show is divided into specifically colored lights – red, green, blue and white are the predominate colors. Vixen is programmed to control all the similar lights (for example, all the red lights that frame windows and doors or all the white lights in small trees). The Windows computer also drives a series of circuits that control a scrolling electronic sign, called an LEDTriks. |
