From instructables user TheHomebrewGuru:
Why not begin an awesome project to spice up those potentially cold, dreary nights with an amazing light show decoration?
In this instructable, I will detail how you can do just that in creating an Audio Modulated Solid State Tesla Coil. Quite a mouthful isn’t it? For those foreign to the electronics engineering field or who simply just have no clue what “audio modulation” or “tesla coils” are, essentially what this device will do is produce visible streamers of electricity into the air (“lightning bolts”) pulsed at frequencies that correspond to audible tones (the device will “turn on and off” so quickly that the vibrations that the streamers make with the air sound like different notes). As we will see, we can exploit this neat effect to have the device play music and control it from behind a computer. So far, the secrets behind how these devices that sometimes make appearances on tv shows and movies has been kept under wraps and exclusively within the electronics engineering and computer science community or for very dedicated hobbyists putting in hours of research. In fact, for many high classes in elite colleges, n00b engineers would even have trouble making this on their own! This project could also be used to FREAK THE LIVING DAYLIGHTS out of people on Halloween! This year, I finished the project just in time to have this prop set up to play an eerie tune and trick-or-treaters were mesmerized (goes great to decorate a Frankenstein set).
This project is not for the light-hearted and is very difficult, but when completed, is extremely rewarding (it took me 2 years to learn how to build and finally do it). Not only will one learn loads about electronics and computer science, but simply taking this device to an event or (safely) to a public space rarely fails to produce a crowd of people taking pictures, impressed with your wizardly h@x0rz skills. Certain types of light bulbs or sticks will magically turn on without any wires. Good skills with power tools, machining, carpentry and the like are essential for crowd appeal. You have been warned, however, that there will be much tweaking, experimenting, and required dedication. In addition, be smart when operating tesla coils around sensitive electronics or in areas occupied by many people (basic common sense, I don’t think there’s much of a need to babble on, but if you are unsure, please work with an experienced engineer).
Cool instructable!
If you’d like to make your own singing Tesla coil but want a little more guidance, take a look at our tinyTesla or oneTeslaTS kits. They are both solid-state Tesla coils that come with MIDI interfaces to play music using electricity itself!