Try Not to Look at this Giant Plasma Tube

Everybody loves plasma globes, but if you are like [zrgzhv], building them as large as possible is the challenge! Definitely a beautiful project, at 7 feet long and 1 foot in diameter, this monster tube makes an impressive display of plasma filaments that slowly move inside. Heck, they almost seem to be alive following the movements of his hand and it’s hard not to become mesmerized by the motion.

seven-foot-plasma-tube-thumbThis tube follows the same principle of operation as its smaller cousin, the plasma globe. Air is evacuated and the tube is filled with a mixture of noble gases, with the particular mixture being responsible for the color of the filaments. Then, high voltage AC is applied to an electrode, which causes the moving tendrils of colored light to extend from the electrode to the outer glass, a phenomenon known as glow discharge. In general, gas-filled tubes can have other uses such as lightning — in the form of fluorescent, neon and xenon lamps — or high power switching as in the thyratron tube, among other applications.

The tube has a weight of over 65 pounds, and needs 300 watts of power to operate from an also homemade power supply. In another video, you can see 10 tubes of different colors working at once. Plasma always makes a great attention-getter; another nice example of its use can be seen in this steampunk lamp which incorporates rotating contacts on the outside of the glass.

Hackaday Prize Entry: A CNC Plasma Table

CNC routers and 3D printers are cool, but the last time I checked, cars and heavy machinery aren’t made out of wood and plastic. If you want a machine that will build other machines, you want a CNC plasma cutter. That’s [willbaden]’s entry for the Hackaday prize. It’s big, massive, and it’s already cutting.

A plasma CNC machine isn’t that much different from a simple CNC router. [will]’s table controller is just a GRBL shield attached to an Arduino, the bearings were stolen from many copy machines, and your motors and drivers are fairly standard, barring the fact they’re excessively huge for a simple 3D printer.

The real trick up [will]’s sleeve is the controller interface. For this, he’s mounted a Raspberry Pi display, a big, shiny, red button, and all the associated electronics behind a beautifully rusty welded enclosure. This part of the build just sends gcode over to the GRBL shield, and is doing so reliably. Right now [will] is looking for some way to save, arrange, and queue jobs on the Pi, a problem that is almost – but not quite – the same job Octoprint does. A software for big, mean CNCs that spew exotic states of matter is an interesting project, and we can’t wait to see where [will] goes with this one.

Arc Lighter become Plasma Pyrography Pen

Wood burning can be quite a striking art form, but who wants to be stuck using an old-fashioned resistive heating element to char wood? You could go with laser engraving, of course, but that seems to take too much of the human touch out of it. So why not try a mini plasma pen and blow torch powered by a fancy cigarette lighter?

Arc lighters are rechargeable electronic lighters that look like a tiny stun-gun, and [NightHawkInLight] has been coming up with some interesting hacks for them. In this case, he extended the electrode leads out and mounted them to a wooden handle. The spark gap is only about 2mm, but the resulting arc is plenty hot enough to char wood with considerable precision. You’ve got to work fast, though, or the high voltage will start finding interesting paths through the char, producing Lichtenberg figures. And if a micro-scale blow torch is a tool you need, [NightHawkInLight] has got that covered too – a small brass tube with a pinched-off nozzle hooked to an aquarium pump provides the pressure for that.

Might there be other applications for this beyond pyrography? Maybe soldering or desoldering? Of non-ESD sensitive components, naturally.

Continue reading “Arc Lighter become Plasma Pyrography Pen”

Electric Compass for a Plasma Cutter

If you are a Maker space or individual lucky enough to own a Plasma Cutter, this electric protractor compass could be handy. The folks over at [MakeItExtreme] built this circle cutting tool to help cut circles and rings in thick metal sheets using their plasma cutter.

The whole thing is built around an electro-magnet, so the jig will only work with magnetic metals. There are not a lot of design details, but it’s possible to infer how to build one looking at the video and the photos on their blog. There’s a couple of nice hacks along the way. Since the electro-magnet is stationary while the rest of the jig rotates, the main mounting bolt had a hole drilled through it to help route the cable. The rotating protractor arm is made from a slab of aluminium and holds all the other parts together – the drive motor, the central hub and the plasma head. The motor used appears to be a 60rpm AC synchro motor. These types usually have an RC phase shifting network between the two coils to allow direction reversal. Friction drive is used to rotate the jig, with the friction coming from a pair of rubber tube bands attached to the electro-magnet and the motor drive hub. The plasma head holder has a rod-end with a roller bearing attached, acting as a caster wheel, ensuring the arc gap is maintained as the jig rotates. A few switches to activate the electro-magnet, motor forward / reverse and plasma enable complete the setup.

Their blog, and YouTube channel has a lot of other interesting projects that they keep building. Check it out.

Continue reading “Electric Compass for a Plasma Cutter”

VHS-Tape-Plasma Mirror Drives Tiny Particle Accelerator

When you think of a particle accelerator, you’re probably thinking of tens of kilometers of tube buried underground, at high vacuum, that uses precisely timed electromagnetic fields to push charged particles like electrons up to amazing speeds (and energies). However, it’s also possible to accelerate electrons in other ways, and lasers are a good bet. Although a laser-based particle accelerator can push electrons very effectively for a few centimeters, they top out at a relatively low maximum “speed” of a couple billion electron-volts, as opposed to the trillions of eV that you can get out of a really big traditional accelerator.

If only you could repeat the laser trick again, “hitting” the already-moving electrons from behind with another beam, you could boost them up to even higher energies. Doing so would take something like a one-way mirror that lets the electrons pass through, but that you could then bounce a laser beam off of. In a fantastic mixture of science and mother-of-invention-style hacking, these scientists from Lawrence Berkeley National Labs use plain-old VHS tape to make plasma mirrors to do just that. Why VHS tape? Because it’s cheap, flexible, and easy to move through the apparatus at high speeds.

The device works like this: a first laser beam passes through a jet of ionized gas and pulls some electrons with it. These electrons are then focused into a beam and pass through some (moving) VHS tape. The electrons punch a hole through the tape. In their wake they leave a hot plasma of mid-90s TV shows you never got around to watching. The second laser beam is then bounced off this plasma mirror and further accelerates the electron beam from behind. In principle, you could repeat this second stage enough times to build up the energy you needed, but for now the crew is working to characterize their single-stage beam. Getting the timing right on the second-stage beam is, naturally, non-trivial.

Anyone who has spent some time in a science lab knows that there are millions of these tiny get-it-done-quick hacks behind the scenes, but it’s nice to see one take center stage as well. If you’ve got stories of great lab hacks that you’d like to see us cover, post up in the comments!

Thanks [Bruce] for the tip, via Science Daily.

11,000 Volt Jacob’s Ladder Sounds Like a Lightsaber

In the high-voltage world, a Jacob’s ladder is truly a sight to behold. They are often associated with mad scientist labs, due to both the awesome visual display and the sound that they make. A Jacob’s ladder is typically very simple. You need a high voltage electricity source and two bare wires. The wires are placed next to each other, almost in parallel. They form a slight “V” shape and are placed vertically. The system acts essentially as a short-circuit. The voltage is high enough to break through the air at the point where the wires are nearest to each other. The air rises as it heats up, moving the current path along with it. The result is the arc slowly raising upwards, extending in length. The sound also lowers in frequency as the arc gets longer, and once [Gristc] tuned his system just right the sound reminds us of the Holy Trilogy.

We’ve seen these made in the past with other types of transformers that typically put out around 15,000 Volts at 30mA. In this case, [Gristc] supersized the design using a much beefier transformer that puts out 11,000 Volts at 300mA. He runs the output from the transformer through eight microwave oven capacitors as a ballast. He says that without this, the system will immediately trip the circuit breakers in his house.

In the demo video below, you can see just how large the arc is. It appears to get about 10 inches long before breaking with a sound different from any Jacob’s ladders we’ve seen in the past as well. Continue reading “11,000 Volt Jacob’s Ladder Sounds Like a Lightsaber”

Illumination Captured in a Vacuum Jar

Experimentation with the unusual nature of things in the world is awesome… especially when the result is smokey glowing plasma. For this relatively simple project, [Peter Zotov] uses the purchase of his new vacuum pump as an excuse to build a mini vacuum chamber and demonstrate the effect his mosfet-based Gouriet-Clapp capacitive three-point oscillator has on it.

In this case, the illumination is caused due to the high-frequency electromagnetic field produced by the Gouriet-Clapp oscillator. [Peter] outlines a build for one of these, consisting of two different wound coils made from coated wire, some capacitors, a mosfet, potentiometer, and heat sink. When the oscillator is placed next to a gas discharge tube, it causes the space to emit light proportionate to the pressure conditions inside.

exploded

For his air tight and nearly air free enclosure, [Peter] uses a small glass jar with a latex glove as the fitting between it and a custom cut acrylic flange. With everything sandwiched snugly together, the vacuum hose inserted through the center of the flange should do its job in removing the air to less than 100 Pa. At this point, when the jar is placed next to the oscillator, it will work its physical magic…

[Peter] has his list of materials and schematics used for this project on his blog if you’re interested in taking a look at them yourself. Admittedly, it’d be helpful to hear a physicist chime in to explain with a bit more clarity how this trick is taking place and whether or not there are any risks involved. In any case, it’s quite the interesting experiment.