Turning and Burning with a CNC Pyrography Machine

With CNC machines, generally the more axes the better. Three-axis machines with a vertical quill over a rectangular workspace are de rigueur, and adding an axis or two can really step up the flexibility of a machine. But can only two axes be of any use? Sure can, as witnessed by this two-axis CNC wood burning machine.

As [tuckershannon] tells the tale, this was a newbie build aided by the local hackerspace. Axis one is a rotary table of laser-cut wood gears powered by a stepper. Axis two is just a stepper and lead screw sitting on a couple of blocks of wood. A Raspberry Pi under the hood controls the motors and cycles the pyrography pen on and off as it scans across a piece of wood on the rotary table, burning a spiral pattern that makes for some interesting art. Hats off to [tuckershannon] for figuring out the math needed to adapt to the changing speed of the pen over the wood as the diameter gets bigger.

We love this build, can’t help but wonder if some clever gearing could eliminate the need for the second stepper. And perhaps an upgrade from the standard resistive wood burner to an arc lighter pyrography pen would improve resolution. Still, it’s hard to argue with results, and this is a great hack.

[via r/raspberrypi]

Thanks to [Liz] for the tip!

You Know You Can Do That with a 555

Hardly a week goes by that we don’t post a project where at least one commenter will lament that the hacker could have just used a 555. [Peter Monta] clearly gets that point of view. For a 555 design contest, he created both digital logic gates and an op amp, all using 555 chips. We can’t quite imagine the post apocalyptic world where the only surviving electronic components are 555 chips, but if that day were to come, [Peter] is your guy.

Using the internal structure of the 555, [Peter] formed a basic logic gate, an inverter, latches, and more. He also composed things like counters and seven-segment decoders. He had a very simple 4-bit CPU design in Verilog that he was going to attempt until he realized it would map into almost 400 chips (half of that if you’d use a dual 555, but still). If you built this successfully, we would probably post it, by the way.  You can see a video of the digital logic counter, below.

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Silicone Molds for Stove-Top Metal Casting

Casting metal parts from 3D-printed plastic or Styrofoam models is all the rage these days, and for good reason — casting is a way to turn one-offs into mass-produced parts. Seems like most of the metal casting projects we feature are aluminum in sand molds, though, so it’s refreshing to see a casting project using silicone molds to cast low-melting point metals.

Don’t get us wrong — sand-cast aluminum is a great method that can even be used to build a lathe from scratch. But not everyone wants to build a foundry and learn the sometimes fussy craft of creating sand molds. [Chris Deprisco] wanted to explore low-melting point bismuth alloys and set about making silicone rubber molds of a 3D-printed Maltese falcon. The bismuth-tin alloy, sold as a substitute for casting lead fishing weights, melts on at 281°F (138°C) and is cool enough for the mold to handle. Initial problems with bubbles in the cast led to a pressure vessel fix, and a dull, grainy surface was fixed by warming the mold before the pour. And unlike sand molds, silicone molds are reusable.

Of course if aluminum is still your material of choice, there’s no need for a complicated foundry. A tuna can, a loaf of bread, and a handful of play sand is all you need to make custom parts.

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A Hypnotizing Interactive Art Piece for Visualizing Color Theory

Digital color theory can be a tricky concept to wrap one’s mind around – particularly if you don’t have experience with digital art. The RGB color model is about as straightforward as digital color mixing gets: you simply set the intensity of red, green, and blue individually. The result is the mixing of the three colors, based on their individual intensity and the combined wavelength of all three. However, this still isn’t nearly as intuitive as mixing paint together like you did in elementary school.

To make RGB color theory more tangible, [Tore Knudsen and Justin Daneman] set out to build a system for mixing digital colors in a way that reflects physical paint mixing. Their creation uses three water-filled containers (one each for red, green, and blue) to adjust the color on the screen. The intensity of each color is increased by pouring more water into the corresponding container, and decreased by removing water with a syringe.

An Arduino is used to detect the water levels, and controls what the user sees on the screen. In one mode, the user can experiment with how the color levels affect the way a picture looks. The game mode is even more interesting, with the goal being to mix colors to match a randomly chosen color that is displayed on the screen.

The practical applications for this project may be somewhat limited, but as an interactive art piece it’s hypnotizing. And, it may just help you with understanding RGB colors for your next project.

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Imaging Magnetism With A Hall Effect Camera

[Peter Jansen] is the creator of the Open Source Tricorder. He built a very small device meant to measure everything, much like the palm-sized science gadget in Star Trek. [Peter] has built an MRI machine that fits on a desktop, and a CT scanner made out of laser-

cut plywood. Needless to say, [Peter] is all about sensing and imaging.

[Peter] is currently working on a new version of his pocket sized science tricorder, and he figured visualizing magnetic fields would be cool. This led to what can only be described as a camera for magnetism instead of light. It’s a device that senses magnetic fields in two directions to produce an image. It’s cool, and oddly, electronically simple at the same time.

Visualizing magnetic fields sounds weird, but it’s actually something we’ve seen before. Last year, [Ted Yapo] built a magnetic imager from a single magnetometer placed on the head of a 3D printer. The idea of this device was to map magnetic field strength and direction by scanning over the build platform of the printer in three dimensions. Yes, it will create an image of field lines coming out of a magnet, but it’s a very slow process.

Instead of using just one magnetic sensor, [Peter] is building a two-dimensional array of magnetic sensors. Basically, it’s just a 12×12 grid of Hall effect sensors wired up to a bunch of analog multiplexers. It’s a complicated bit of routing, but building the device really isn’t hard; all the parts are easily hand-solderable.

While this isn’t technically a camera as [Peter] would need box or lens for that, it is a fantastic way to visualize magnetic fields. [Peter] can visualize magnets on his laptop screen, with red representing a North pole and green representing the South pole. Apparently, transformers and motors look really, really cool, and this is a perfect proof of concept for the next revision of [Peter]’s tricorder. You can check out a video of this ‘camera’ in action below.

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Full Color PCB Business Card

[Sjaak], in electronic hobbyist tradition, started to design a PCB business card. However, he quickly became disillusioned with the coloring options made available by the standard PCB manufacturing process. While most learn to work with a limited color palette, [Sjaak] had another idea. PCB decals for full-color control.

As [Sjaak] realized early in his PCB journey, the downside of all PCB business cards (and PCBs in general) is the limited number of colors you can use which are dictated by the layers you have to work with: FR4, soldermask, silkscreen and bare copper. Some people get crafty, creating new color combinations by stacking layers for hues, but even that technique doesn’t come close to a full palette.

The commercial off-the-shelf out of the box solution [Sjaak] found was decal slide paper. For those of you not prone to candle making or car decorating, decals are printable plastic film that can be used to decorate ceramics, glass or other smooth surfaces. Both clear and white versions can be found in most hobby stores. Once obtained, an inkjet or laser printer can print directly onto the photo paper-like material, lending the decals an infinite range of colors.

[Sjaak] bought clear film and designed his PCB with black soldermask and white silkscreen. Once the PCBs had come in, [Sjaak] got to work applying the decals with a transfer method by placing one into water, waiting a bit until the decal lets loose and then are carefully applied to a PCB. [Sjaak] reports that the process is a bit trickery because the film is very thin and is easily crinkled. But, difficulties overcome, the PCB then needs to dry for twenty-four hours. From there, it’s into the oven for 10 minutes at 248 degrees Fahrenheit (120 degrees Celsius) followed by an optional clear coating. Although the process is a bit involved, judging from his pictures we think the results are worth it, producing something that would stand out; which, in the end, is the goal of a PCB business card.

With all this in mind, we think that the logical progression is to incorporate digital logic or go full DIY and CNC or laser engrave your own business card.

Ink-Filled Machine Badges Score Respect for Your Gear

Remember the good old days when machines had a stout metal badge instead of cheap vinyl decals, and nameplates on motors were engraved in metal rather than printed on a label with a QR code? Neither do we, but these raised brass labels with color filled backgrounds look great, they’re surprisingly easy to make, and just the thing your gear needs to demand respect as a cherished piece of gear.

The ‘easy’ part of this only comes if you have access to a machine shop like [John] at NYC CNC does. To be fair, the only key machine for making these plates is a laser cutter, and even a guy like [John] needed to farm that out. The process is very straightforward — a brass plate is cleaned and coated with lacquer, which is then removed by the laser in the areas that are to be etched. The plate is dipped in an electrolyte solution for etching, cleaned, and powder coated. After curing the powder coat with a heat gun rather than an oven — a tip worth the price of admission by itself — the paint is sanded off the raised areas, the metal is polished, and a clear coat applied to protect the badge.

Plates like these would look great for a little retro-flair on a new build like this Nixie power meter, or allow you to restore a vintage machine like this classic forge blower.

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