The folks of ArcAttack - a crazy group of performers who use singing tesla coils to create incredible melodies - have built a lightning-proof guitar for a performance on America's Got Talent. They've decided to tell us how they constructed the instrument and how it works:
The fret board is 72 optically isolated switches. The fret board, instead of frets has 6 brass contacts per fret. When the string is pushed down to the contact, it makes a connection.
From there the signal is optically isolated, to protect from EMF and sent to a micro controller thats only job is to priority encode the fretboard, and keep tabs on which string is pushed down to each fret.
So priority encoding means this basically: if you are playing the 6th string on the 12th fret, then the computer ignores if say the 11th and 10th frets are pressed on that string also, since the 12th fret needs to take priority - just like a real guitar.
Now there is a second computer that is located on top of the fret board underneath the metal box. This computer detects when the strings are strummed, and is also updated by the first computer whenever the fretboard changes state.
It is also the second computer's responsibility to process the fretboard and strumming data, and output midi messages accordingly. The midi signal is converted to a fibre optic light pulse, and is sent down as optical data to the Tesla coil's main computer, which is responsible for processing the midi commands and outputting a pulse rate modulation signal to control the pitch of the tesla coils.
The end result: The most rock and roll display ever. Real lightning guitar, while the player plays the guitar, he is being struck by lightning that produces the melody that he is playing.
At this point, most educated people think we were just holding it as a prop, or deeming it fake. Hehe. I guess I'm flattered. NOPE. It was real. Most everyone else just doesn't get it.
The entire time that Tony (the first faraday suit performer) was in the spark, he was in full control of the tesla coil melody until he walked out of the spark, at which point our control computer took over and played the solo of the song. It's rather difficult to play the guitar with chain mail gloves on, so we had to keep it fairly simple for him.
The guitar is protected from the lightning via optically coupled switches, and exceptionally clever shielding.
The creation of this instrument sounds as crazy and involved as an ArcAttack performance, but you can actually see one of those performances yourself on the September 8 airing of America's Got Talent. At that time you can also choose to support the group with votes if you enjoy what you see - but please do keep the voting rules in mind.