Throughout the maker pavilion, the siren song of a musical Tesla coil could be heard. Those who followed their ears found themselves at the oneTesla booth. OneTesla is a hobby Tesla coil, with the added twist of polyphonic MIDI input.
Started by three MIT students, oneTesla had a successful Kickstarter campaign last year. Like many kickstarters, they are a bit behind in the shipping department. They are shipping out their third run of kits to backers now. The group had a small number of oneTesla coils for sale at the show, which appeared to have sold out by midday Sunday.
The actual process of generating sound with a Tesla coil is fascinating. All Tesla coils are resonant at high frequency. In oneTesla’s case, this is 220kHz. Human hearing ends around 20kHz, so this is well beyond the range of perception. Since the coil is locked in at this frequency, the power to the coil is modulated at the desired sound frequency. Playing an A note for example, would mean modulating the coil at 440Hz.
In OneTesla, all this is handled by the MIDI interrupter board. An ATMega328 performs all the heavy lifting of modulating the coil. Even more interesting is the fact that the MIDI interrupter can create two note polyphony by interleaving the modulated notes. Think persistence of vision style effects, but with audio. The interrupter also acts as the overall power control for the coil, eliminating the need for a variac on the AC side to control overall coil power.
11 thoughts on “OneTesla Electrifies Maker Faire NY 2013”
That was neat but incredibly obnoxious to those nearby… I think the tune is just starting to fade from my memory!
Yeah, I heard it on a 20-second video clip from another project… almost like torture for those stuck in a booth nearby!
True, next time we need a booth away from the others! We kept the coil on even less than half power the whole time because of the volume. Apologies to those around us– we warned the organizers that it would be loud!
Now I want to make a keyboard with a tesla coil in it
Soo, are we supposed to be impressed with 2 note polyphony? How about the one made by The Geek Group that plays 12 notes at once?
It’s more of a limitation of the DRSSTC itself not to sound good playing more than two notes at once.
Because? You can play any tone and have some control over amplitude using duty cycle, you should be able to play any number of notes at the same time, the only limitation being the software calculating on and off times.
You call that a Tesla Coil? THIS is a Tesla Coil:
ArcAttack at ATX Hackerspace,
I want an even smaller Tesla coil than this desktop model (about half the size of this one) to have on my desk at work for shenanigans.
ArcAttack is just a bunch of adobe after effects…..and they smell like feet
Please be kind and respectful to help make the comments section excellent. (Comment Policy)