[GreatScott!] needs to light off fireworks with an arc rather than a flame, because “fireworks and plasma” is cooler than fireworks and no plasma. To that end, he attempted to reverse engineer an arc lighter, but an epoxy potted high-voltage assembly thwarted him. Refusing to accept defeat, he modified a CCFL inverter into an arc lighter, and the process is pretty educational.
With his usual impeccable handwriting and schematic drawing skills, [GreatScott!] documents that his CCFL inverter is a resonant Royer oscillator producing a sine wave of about 37 kHz, which is then boosted to about 2400 volts. That’s pretty good, but nowhere near the 15 kilovolts needed for a self-sustaining arc across electrodes placed 5 mm apart. A little math told him that he could achieve this by rewinding the transformer’s primary with only 4 turns. After some testing, the rewound transformer was fitted back into the Royer circuit and with a few modifications the arc was struck.
It’s not a finished project yet, and we’re looking forward to seeing how [GreatScott!] puts this to use. For now, we’re grateful for the lesson is Royer oscillators and rewinding transformers. But if you’d rather hack an off-the-shelf arc lighter, there’s always this arc lighter pyrography pen, or this mini plasma cutter.
I did something similar by using a CCFL-Inverter from a TFT computer monitor, but I coupled an audio signal into the brigtness-signal normally controlled by the main microcontroller, which basically is a plasma-speaker:
https://rof.li/files/plasmaspeaker.webm
I just found another video of that experiment where I use two screws as electrodes, which works better:
https://rof.li/files/plasma2.webm
Great Scott is great !
This guys DaveCAD is like on some whole other level. It’s like DaveCAD 11, most people I see are still on DaveCAD 2.0
Including Dave himself.
Awesome! My brother and I did this years ago too
Instead of placing the fuse directly into the arc, we upped the voltage and attached the electrodes to two nuts (spaced ~10mm vertically from eachother) with the fuse passing through the centres. Basically the electrodes touch the fuse.
This causes the arc to form inside the fuse (as the carbon content makes it mildly conductive), causing it to combust from the inside out. Perfect ignition every time, and the voltage is sufficiently high enough to pierce through any crud formed onto the electrodes by the combustion process
I like this!
The production quality & value on these Vids is impressive!
HaD once again shows me another channel to follow.
he also inadvertently made an am arc transmitter having that run at ~300khz
One of Great Scott’s ancestors is a pen plotter ;-)
I used a similar power supply from an old fluorescent display to build a tiny battery powered electrocautery device (like a doctor would use to burn off a wart). The human body provides sufficient ground so you only need a single electrode to singe tissue. And because the power is so low, it’s virtually painless.
GreatCAD is based on Eagle, both are german and in Germany “Ordnyng muß sein!”
The potting on those electric arc lighters may be primarily a safety measure. I doubt that they contain any “secrets”.
When he is done setting off fireworks he can do a “Cody” and pull some nitrogen out of the air with it, for making even more fireworks. Personally I don’t see the point of exploding stuff in the sky, but if it is legal in your part of the world and you get your jollies from it, why not, just don’t blame anyone other than yourself if you end up with less fingers than when you started.
An electrician I knew would use a paperclip, 5 meters of 12 gauge wire, and a 12V battery to light his fireworks. The paperclip was across the wires on one end, and the 12V battery would be touched momentarily across the other end. The fireworks fuse was wrapped around the paper clip. When the current would flow, the paperclip would get hot and light the fuse. Simple.