Fablab Saigon Celebrates A Belated Arduino Day

Okay, we’ve just left May and stepped into June, why are we talking about Arduino Day — traditionally a March 16th event where makers congregate and share projects? I live in Ho Chi Minh City, and the event tends to take place in mid-May, but the enthusiasm and collaborative spirit are just as strong. Organized by the awesome local maker group Fablab Saigon with the venue provided by Intek Institute, there were some neat projects on display along with some talks from local companies.

The first thing that struck me about the event was how young the maker movement is here – most attendees were still in high school or early university. By contrast, I was 23 when I first learned to use AVR microcontrollers with assembly language (by the time Arduino started to get traction the boat effectively missed me). I couldn’t help but feel like a bit of a relic, at least until we all started talking excitedly about robots (I had brought a couple). It seems that geeking out about electronics is the great equalizer which knows no age limits.

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A Tesla Coil From PCBs

While at the Hacker Hotel camp in the Netherlands back in February, our attention was diverted to an unusual project. [Niklas Fauth] had bought along a Tesla coil, but it was no ordinary Tesla coil. Instead of the usual tall coil and doughnut-shaped capacity hat it took the form of a stack of PCBs with spacers between them, and because Tesla coils are simply cooler that way, he had it playing music as an impromptu MIDI-driven plasma-ball lousdpeaker. Now he’s been able to write up the project we can take a closer look, and it makes for a fascinating intro not only to double-resonant Tesla coils but also to Galium Nitride transistors.

The limiting factor on Tesla coils comes from the abilities of a transistor to efficiently switch at higher frequencies. Few designs make it above the tens of kHz switching frequencies, and thus they rely on the large coils we’re used to. A PCB coil can not practically have enough inductance for these lower frequencies, thus Niklas’ design employs a very high frequency indeed for a Tesla coil design, 2.6 MHz with both primary and secondary coils being resonant. His write-up sets out in detail the shortcomings of conventional MOSFETS and bipolar transistors in this application, and sets out his design choices in using the GaN FETs. The device he’s using is the TI LMG5200 GaN half-bridge driver, that includes all the necessary circuitry to produce the GaN FET’s demanding drive requirements.

The design files can be found in a GitHub repository, and you can see a chorus of three of them in action in the video below. Meanwhile [Niklas] is a prolific hardware hacker whose work has appeared on these pages in the past, so take a look at his ultrasonic phased array and his x-ray image sensor work.

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Here’s A Tesla Coil You Can Wear

It’s badgelife season, and if you need an idea for a killer piece of wearable electronics, look no further than this PCB Tesla coil. Yes, it’s killer, doubly so if you’re wearing a pacemaker.

This project was inspired by an earlier Tesla coil on a PCB project that used 160 turns of 6 mil traces on a circuit board as the secondary. All the electronics are there, and it’s powered by USB. Plug this thing in, and you have a pocket full of lightning that’s approximately 30kV. It probably won’t kill you if you touch it, but let’s not test that too much. [Bobricious] took this idea and ran with it, stripping the circuit down to its bare minimum. Now it’s just a single transistor, with all the other parts printed on a circuit board.

There is one problem with making a Tesla Coil on a PCB, and that’s the number of turns on the coil. Any Tesla coil you’ll find is really just the clever application of a single thin wire wrapped around itself a few hundred or thousands of times. This Tesla coil is no different, and in this case it’s 240 turns of a single trace wrapping around a PCB that is 150mm square. [Bobricius] is one of the kings of putting tiny coils on a PCB, and his fiberglass brushless motor is a testament to that. We also just covered his circular linear motor raceway which also uses PCB coils.

The circuit is simple, just a power jack that accepts something around 20 Volts, a single BD243 transistor, an LED, and an 82k resistor. With that, you can lay a small neon tube on the PCB and watch it light up. With another PCB and another neon tube, this circuit board can transfer wireless power. It’s a fun toy, and it’s all PCB tech.

Tesla Coil Uses Vacuum Tube

What do you do when you find a 5 kW transmitting tube in your local electronics store? If you are [TannerTech], you build a vacuum tube tesla coil. This isn’t the usual little wimpy coil, but a big bad boy that would look at home in an old horror movie.

The first power up was a bit anticlimactic, although it was working, it wasn’t very spectacular other than the tube glowing brightly. A few adjustments and some mineral oil did the trick.

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Low-End Parts Make Tesla Coil With A High-End Look

We all know the saying: cheap, fast, or good — pick any two. That rule seems to apply across the spectrum of hackerdom, from software projects to hardware builds. But this DIY Tesla coil build might just manage to deliver on all three.

Cheap? [Jay Bowles]’ Tesla coil is based on a handheld bug zapper that you can find for a couple of bucks, or borrow from the top of the fridge in the relatively bug-free winter months. The spark gap is just a couple of screws set into scraps of nylon cutting board — nothing fancy there. Fast? Almost everything needed to build this is stuff lying around the house, and depending on the state of your junk bin you may not even have to order the polypropylene caps [Jay] recommends. Good? That’s a relative term, of course, and if you define it as a coil capable of putting out pumpkin-slaying lightning bolts or playing “Yakkity Sax”, you’ll likely be disappointed. But there’s no denying that this Tesla coil looks good, from its Lexan base to the door-pull top load. And running off a couple of AA batteries, it’s safe to use too.

[Jay] put a lot of care into winding and dressing the secondary coil neatly, and the whole thing would look great as a desktop toy. Not into the winding part? You can always etch a PCB Tesla coil instead.

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PCB Tesla Coil Is Perfect Desk Toy

A Tesla coil easily makes it to the top spot on our list of “Mad Scientist” equipment we want for the lab, second only to maybe a Jacob’s Ladder. Even then, it’s kind of unfair advantage because you know people only want a Jacob’s Ladder for that awesome sound it makes. Sound effects not withstanding, it’s Tesla coil all the way, no question.

Unfortunately, winding your own Tesla coil is kind of a hassle. Even on relatively small builds, you’ll generally need to setup some kind of winding jig just to do the secondary coil, which can be a project in itself. So when [Daniel Eindhoven] sent his no-wind Tesla coil into the tip line, it immediately got our attention.

The genius in his design is that the coils are actually etched into the PCB, completely taking the human effort out of the equation. Made up of 6 mil traces with 6 mil separation, the PCB coil manages to pack a 25 meter long, 160 turn coil into an incredibly compact package. As you might expect, such a tiny Tesla coil isn’t exactly going to be a powerhouse, and in fact [Daniel] has managed to get the entirely thing running on the 500 mA output of your standard USB 2.0 port.

In such a low-power setup, [Daniel] was also able to replace the traditional spark gap pulse generator with a PIC18F14K50 microcontroller, further simplifying the design. An advantage of using a microcontroller for the pulse generator is that it’s very easy to adjust the coil’s operating frequency, allowing for neat tricks like making the coil “sing” by bringing its frequency into the audible range.

For those looking to build their own version, [Daniel] has put the PCB schematic and firmware available for download on his site. He also mentions that, in collaboration with Elektor magazine, he will be producing a kit in the near future. Definitely something we’ll be keeping an eye out for.

Incidentally, this isn’t the first time [Daniel] has demonstrated his mastery of high voltage. He scared impressed us all the way back in 2010 with his 11,344 Joule capacitor bank, perfect for that laptop-destroying rail gun you’ve been meaning to build.

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Catching 30 Kilowatts With Thor’s Hammer

Can you really catch lightning with Mjolnir, the mythical hammer of Thor? If you’re [James Hobson] you can get pretty darn close. He’s a long time writer at Hackaday who’s been building an epic following on his YouTube channel by making the digital effects of blockbuster movies into practical effects. Today he released a video showing how he channeled a jolt of lightning with hammer held high.

The lightning source for this hack is a huge Tesla coil held overhead by a telescoping lift. Humans and high voltage mix poorly, which is why you can’t actually tell this is [James]. He’s wearing a full body suit of grounded chainmail which serves as a Faraday cage, safely directing the current around him to avoid a literally heart-stopping moment. Check out the antics in the video after the break.

Longtime readers will remember [Caleb Kraft’s] take on Mjolnir, a build that placed the Tesla coil in the hammer itself. [James]’ version is undeniably more impressive, with the tradeoff that it’s wholly unportable. While we’re on the topic of mythical hammers, our other most favorite build is the delightful prank build which makes the hammer unliftable except by the recognized owner.

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