Extremely Simple Tesla Coil With Only 3 Components

January 12, 2021 by 22 Comments

Tesla Coils are a favourite here at Hackaday – just try searching through the archives, and see the number of results you get for all types of cool projects. [mircemk] adds to this list with his Extremely simple Tesla Coil with only 3 Components. But Be Warned — most Tesla coil designs can be dangerous and ought to be handled with care — and this one particularly so. It connects directly to the 220 V utility supply. If you touch any exposed, conductive part on the primary side, “Not only will it kill You, it will hurt the whole time you’re dying”. Making sure there is an ELCB in the supply line will ensure such an eventuality does not happen.

No prizes for guessing that the circuit is straight forward. It can be built with parts lying around the typical hacker den. Since the coil runs directly off 220 V, [mircemk] uses a pair of fluorescent lamp ballasts (chokes) to limit current flow. And if ballasts are hard to come by, you can use incandescent filament lamps instead. The function of the “spark gap” is done by either a modified door bell or a 220 V relay. This repeatedly charges the capacitor and connects it across the primary coil, setting up the resonant current flow between them. The rest of the parts are what you would expect to see in any Tesla coil. A high voltage rating capacitor and a few turns of heavy gauge copper wire form the primary LC oscillator tank circuit, while the secondary is about 1000 turns of thinner copper wire. Depending on the exact gauge of wires used, number of turns and the diameter of the coils, you may need to experiment with the value of the capacitor to obtain the most electrifying output.

If you have to look for one advantage of such a circuit, it’s that there is not much that can fail in terms of components, other than the doorbell / relay, making it a very robust, long lasting solution. If you’d rather build something less dangerous, do check out the huge collection of Tesla Coil projects that we have featured over the years.

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Vertical Mill Completes Scrapyard Lathe Build

January 12, 2021 by 12 Comments

One thing’s for sure: after seeing [Roland Van Roy] build a vertical mill from industrial scrap, we’ve got to find a better quality industrial scrapyard to hang around.

The story of this build started, as many good shop stories do, at the lathe, which in this case was also a scrapyard build that we somehow managed to miss when it first posted. This lathe is decidedly different from the common “Gingery method” we’ve seen a few times, which relies on aluminum castings. Instead, [Roland] built his machine from plate stock, linear slides, and various cast-off bits of industrial machines.

To make his lathe yet more useful, [Roland] undertook this build, which consists of a gantry mounted over the bed of the lathe. The carriage translates left and right along the bed while the spindle, whose axis lines up perfectly with the center axis of the lathe, moves up and down. [Roland] added a platform and a clever vise to the lathe carriage; the lathe tool post and the tailstock are removed to make room for these mods, but can be added back quickly when needed. Digital calipers stand in for digital read-outs (DROs), with custom software running on a Picaxe and a homebrew controller taking care of spindle speed control.

[Roland] reports that the machine, weighing in at about 100 kg, exhibits a fair amount of vibration, which limits him to lighter cuts and softer materials. But it’s still an impressive build, and what really grabbed us was the wealth of tips and tricks we picked up. [Roland] used a ton of interesting methods to make sure everything stayed neat and square, such as the special jig he built for drilling holes in the T-slot extrusions to the use of cyanoacrylate glue for temporary fixturing.

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Remote Control Robot Deals Dominoes

January 12, 2021 by 5 Comments

Oh, dominoes — the fun of knocking them down is inversely proportional to the pain of setting them all up again. [DIY Machines] is saving loads of time by automating the boring part with a remote control domino-laying machine. If only it could pick them back up.

This machine can be driven directly over Bluetooth like an R/C car, or programmed to follow a predetermined path via Arduino code. Here’s how it works: an Arduino Uno drives two servos and one motor. The 1:90 geared motor drives the robot around using a 180° servo to steer. A continuous servo turns the carousel, which holds nearly 140 dominoes. We love that the carousel is designed to be hot-swappable, so you can keep a spare ready to go.

[DIY Machines] really thought of everything. Every dozen or so dominoes, the machine leaves a gap in case one of the dominoes is tipped prematurely. There are also a couple of accessories for it, like a speedy domino loading stick and a fun little staircase bridge to add to your domino creations. Though all the machine files are freely available, [DIY Machines] requests a small donation for the accessories files. Check out the complete build video after the break, followed by a bonus video that focuses on upgrading the machine with an HM10 Bluetooth module for controlling it directly with a phone.

This certainly isn’t the first domino-laying device we’ve seen, though it might be the most accessorized. [Matthias Wandel]’s version uses only one motor to move and deal the dominoes.

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Visualizing Ionizing Radiation With DIY Plastic Scintillators

January 12, 2021 by 16 Comments

Although most types of radiation are invisible, except for the visible part of the EM spectrum, there are many ways that we can make various types of radiation visible. One of these methods is called ‘scintillation’, which can be used to make ionizing radiation visible. Recently [Lukas Springer] demonstrated how to make scintillators out of what is essentially plastic: bisphenol-A (E45, ‘epoxy’) resin with hardener and other additives.

The essential principle of operation behind a scintillator is its sensitivity to ionizing radiation, along with the tendency to absorb the energy and re-emit it in the form of light, i.e. luminescence. This is akin to the luminescence of LEDs, except that in their case the underlying principle is that of electro-luminescence. In the case of a plastic scintillator, the scintillating material is suspended in the solid polymer matrix base.

As [Lukas] points out, plastic scintillators are hardly ideal when it comes to their sensitivity to ionizing radiation, but they compensate for this by being easy to shape and produce, while being very durable. For this experiment, he used regular epoxy as the scintillator matrix, p-Terphenyl as primary scintillator and Coumarin 102 as the wavelength shifter. These three compounds act as a reaction chain, with the matrix absorbing the radiation and transferring it to the primary scintillator, which in turns emits the energy as light.

As the primary scintillator tends to radiate in the deep UV part of the EM spectrum, a wavelength shifter (i.e. secondary scintillator) which ‘shifts’ the emitted UV radiation into the visible part of the spectrum.

After producing a batch of plastic scintillators following the above recipe, [Lukas] irradiated them with gamma radiation, and found them to perform worse than some already not remarkable Russian PS-based scintillators. [Lukas’s] guess is that the matrix may be absorbing the primary scintillator’s output, or a mismatch between the primary and second scintillator.

While tricky to get right, it does seem like a fun hobby if one has some interesting in chemistry. [Lukas] (@GigaBecquerel on Twitter) provides a basic recipe as well as many other compounds to use for the primary and secondary scintillator, as well as the matrix compound. Enough to get started with.

Death Of The Serial Squid: When Do You Give Up?

January 12, 2021 by 46 Comments

While searching for a connector recently, I revisited an old project of mine called the Serial Squid. This was to have been my first open-source hardware design. After completing the entire design, PCB, BOM, and preparing for a crowd-funded campaign, I eventually gave up for reasons discussed below, I’ve always thought of this as a failure, but on further reflection I see it in a new light. There were some good lessons learned along the path to abandonment.

When do you let go?  When should you push through? Continue reading “Death Of The Serial Squid: When Do You Give Up?” →

HackadayU Announces Rhino, Mech Eng, And AVR Classes During Winter Session

January 12, 2021 by 13 Comments

The winter lineup of HackadayU courses has just been announced, get your tickets now!

Spend those indoor hours leveling up your skills — on offer are classes to learn how to prototype like a mechanical engineer, how to create precision 3D models in Rhino, or how to dive through abstraction for total control of AVR microcontrollers. Each course is led by an expert instructor over five classes held live via weekly video chats, plus a set of office hours for further interaction.

  • Introduction to 3D using Rhino
    • Instructor: James McBennett
    • Course overview: Introduces students to Rhino3D, a NURBS based 3D software that contains a little of everything, making it James’ favorite software to introduce students to 3D. Classes are on Tuesdays at 6pm EST beginning January 26th
  • Prototyping in Mechanical Engineering
    • Instructor: Will Fischer
    • Course overview: The tips and tricks from years of prototyping and mechanical system design will help you learn to think about the world as a mechanical engineer does. Classes are on Tuesdays at 1pm EST beginning January 26th
  • AVR: Architecture, Assembly, & Reverse Engineering
    • Instructor: Uri Shaked
    • Course overview: Explore the internals of AVR architecture; reverse engineer the code generated by the compiler, learn the AVR assembly language, and look at the different peripherals and the registers that control their behavior. Classes are on Wednesdays at 2pm EST beginning January 27th

Consider becoming an Engineering Liaison for HackadayU. These volunteers help keep the class humming along for the best experience for students and instructors alike. Liaison applications are now open.

HackadayU courses are “pay-as-you-wish” with a $10 suggested donation; all proceeds go to charity with 2019 contributions topping $10,100 going to STEAM:CODERS. There is a $1 minimum to help ensure the live seats don’t go to waste. Intro videos for each course from the instructors themselves are found below, and don’t forget to check out the excellent HackadayU courses from 2020.

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Baby Yoda Becomes Personable Robot

January 12, 2021 by 6 Comments

Baby Yoda has been a hit character in Disney’s The Mandalorian, but does not actually exist in real life as far as we know. Instead, [Manuel Ahumada] set about building a robotic replica, complete with artificial intelligence.  (Video, embedded below.)

The first step was to build a basic robotic simulcra of Baby Yoda, which [Manuel] achieved by outfitting a toy with servos, motors and a Raspberry Pi. With everything hooked up, Baby Yoda was able to move his head and arms, and scoot around on wheels, all under the control of a Bluetooth gamepad. With that sorted, [Manuel] added brains in the form of a smartphone running Intel’s OpenBot machine learning platform. This allows Baby Yoda to track and follow people it sees on its smartphone camera, and potentially even navigate real-world spaces with future upgrades.

It’s a fun build, and we’d love to see the bot let loose at a convention to explore and make friends. We’ve covered OpenBot before, and look forward to seeing it used in more builds. Video after the break.

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