3D Printed Forge For Recycling

March 27, 2022 by 30 Comments

If you own a CNC and have kept tabs on metal prices these past few years (honestly months), you might shed a small tear as you watch chips fly off your work and into the trash. With a sigh, these flecks and pieces are consigned to be the cost of machining a part. Thankfully, the fine folks at [ActionBox] have been working on a 3d printed plaster forge for recycling their metal scraps.

The team ordered some graphite crucibles of a few sizes from a large online bookstore and started 3D printing some molds for crucible holders. They started with a smaller version to try the method. While the walls were too thin in that initial version, the approach was proven. With slightly thicker walls, the medium-sized version worked much better. The goal of the forge was to smelt copper as they had a lot of thick copper wire lying around. Armed with several propane torches, they started melting aluminum and brass, which worked reasonably well. However, the melting point of copper continued to elude them (1984°F or 1085°C).  To counter this, the [ActionBox] team bought some new torches that provided significantly higher BTU output, while still fitting the holes in the mold. This did the trick!

The mold to accommodate the large crucible was massive and printed in four sections. The team did melt copper successfully and had four ingots to show off. We want to stress how dangerous molten copper and other metals are, particularly regarding things you might not realize have moisture soaked up inside. Proper PPE is essential to use these things without getting hurt. [ActionBox] has some helpful pointers in that area, but they admit they are relatively new to forging and casting themselves. Perhaps version two can incorporate a flip lid for added safety.

Video after the break.
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ESP32 composite library with LVGL demo. (Credit: aquaticus)

Generating Composite Video On ESP32 With LVGL GUI

March 27, 2022 by 12 Comments
RCA connector mounted to ESP32 board. (Credit: aquaticus)
RCA connector mounted to ESP32 board. (Credit: aquaticus)

Just because a microcontroller doesn’t have a dedicated video peripheral doesn’t mean it cannot output a video signal. This is demonstrated once again, this time on the ESP32 by [aquaticus] with a library that generates PAL/SECAM and NTSC composite signals. As a finishing touch on the hardware side, [aqaticus] added an RCA jack is an optional extra. The composite signal itself is generated on GPIO 25, with the selection from a wide number of PAL and NTSC resolutions.

In addition, LVGL support is integrated: this is an open-source library that provides a cross-platform way to provide graphical UIs for embedded platforms. Using this combination any ESP32 can generate a fully graphical UI on a monochrome or color display to add some extra flair and functionality to an ESP32 project.

Currently, this library does not support color output, but hopefully this will be added in the future. Even so, together with simple VGA output using a DAC, this library provides yet another way to add analog video output to ubiquitous MCUs like the ESP32. Even if these MCUs are not going to be decoding any video formats at a reasonable speed, adding a UI that’s more user-friendly than an HD44780-based display and a few buttons can really elevate the user experience.

Chris playing his tiny pinball machine

Tiny Pinball Is As Cute As Pi

March 27, 2022 by 8 Comments

Pinball machines are large, complex, and heavy boxes of joy and delight. However, when you don’t have the money or space for one, you have to make your own mini Raspberry Pi-powered one.

With access to a local makerspace and a bit of extra free time, [Chris Dalke] had plans to capture the flavor of a full-scale pinball machine in a small package. Laser-cut Baltic birch forms the enclosure, and a screen makes up the playing field rather than a physical ball. An Arduino Uno handles the three buttons, the four LED matrixes, and a solenoid for haptic feedback, communicating

with the Pi via serial. Unfortunately, even with a relatively decent

volume inside, it is still a tight squeeze.

Rather than use an off-the-shelf pinball game, [Chris] wrote his own in C using raylib and raygui, two handy libraries that can be included in the project quickly. SQLLite3 writes high scores out to disk. All in all, an inspiring project that has a very high level of polish.

If you’re looking for a tiny pinball machine but want more of the classic pinball feel, why not look at this scale pinball machine?

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Peltier Cloud Chamber Produces Some Lovely Trails

March 27, 2022 by 6 Comments

[Advanced Tinkering] over on YouTube has some pretty unique content, on subjects of chemistry and physics that are a little more, interesting let’s say — anyone fancy distilling cesium? The subject of this build is the visualization of ionizing radiation tracks, with one of our old favorite physics demonstrators, the venerable cloud chamber. The build video (embedded below,) shows the basic construction and performance of a Peltier effect cooler setup. The system is used to create a layer of supersaturated (and cold) alcohol vapor in which the radiation source or other experiment can be immersed.

Peltier modules are a great solution for moving heat from one surface to another, but they are not terribly efficient at it, especially if you don’t keep the hot side temperature in check. Effectively they are a short-distance heat pump, so you need to dump the hot-side heat elsewhere. The method [Advanced Tinkering] chose here was to use a pair of off-the-shelf water cooling blocks, mounted into a 3D printed plate. The hot side dumps into a pair of fan-cooled radiators. Four double-layer Peltier modules are wired in parallel to a 60A power supply, which seems like a lot, but Peltier modules are hungry little things. A reasonable amount of power is needed to drive the cooling fans and water pump. The vapor source is a simple pad of liquid alcohol at the top of the stack, just above a metal screen which is held at a high voltage. The vertical electric field allows visualization of the charge of emitted particles, which will curve up or down depending on their polarity.

As can be seen from the second video linked below, some really nice cloud trails are produced, so it looks like they got the setup just right!

Do you need all this complexity to visualize simple radiation paths? No, you don’t, but just temper your expectations. Peltier-based builds are not uncommon, here’s another one, but some builders say they’re not very robust, so this build uses phase-change technology instead for some serious runtimes.

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Who Needs Yeast When You Have Lab Equipment?

March 26, 2022 by 32 Comments

This particular story on researchers successfully making yeast-free pizza dough has been making the rounds. As usual with stories written from a scientific angle, it’s worth digging into the details for some interesting bits. We took a look at the actual research paper and there are a few curious details worth sharing. Turns out that this isn’t the first method for yeast-free baking that has been developed, but it is the first method to combine leavening and baking together for a result on par with traditional bread-making processes.

Some different results from varying the amount of pressure released during the baking process.

Basically, a dough consisting of water, flour, and salt go into a hot autoclave (the header image shows a piece of dough as seen through the viewing window.) The autoclave pressurizes, forcing gasses into the dough in a process similar to carbonating beverages. Pressure is then released in a controlled fashion while the dough bakes and solidifies, and careful tuning of this process is what controls how the bread turns out.

With the right heat and pressure curve, researchers created a pizza whose crust was not only pleasing and tasty, but with a quality comparable to traditional methods.

How this idea came about is interesting in itself. One of the researchers developed a new method for thermosetting polyurethane, and realized that bread and polyurethane have something in common: they both require a foaming (proofing in the case of bread) and curing (baking in the case of bread) process. Performing the two processes concurrently with the correct balance yields the best product: optimized thermal insulation in the case of polyurethane, and a tasty and texturally-pleasing result in the case of pizza dough. After that, it was just a matter of experimentation to find the right balance.

The pressures (up to 6 bar) and temperatures (145° Celsius) involved are even pretty mild, relatively speaking, which could bode well for home-based pizza experimenters.

Hacker Camps Are Back. To Get You In The Mood, Here’s A Story From 1997

March 26, 2022 by 6 Comments

The past couple of years of the COVID pandemic have been rough in some unexpected ways, and it’s clear that our world will never be quite the same as it was beforehand. In our community, the hackerspaces are open again, and while the pandemic hasn’t gone away this year shows the promise of hosting the first major hacker camps to be held since 2019. We’re sure a number of you will be making your way to them. To give a taste of what is to come we’ve got a rare glimpse into hacker camps past.

The Netherlands events are held every four years outside pandemic disruptions, and we’re going back as far as 1997 for HIP, or Hacking In Progress, where [Christine Karman] kept a daily diary of the event. 25 years later it’s both a familiar account of a hacker camp and an interesting glimpse into a time when for much of the wider population an Internet connection was still a novelty. Continue reading “Hacker Camps Are Back. To Get You In The Mood, Here’s A Story From 1997” →

ATtiny85 Snake Game Is A Circuit Sandwich

March 26, 2022 by 3 Comments

If there’s any looming, unwritten rule of learning a programming language, it states that one must break in the syntax by printing Hello, World! in some form or another. If any such rule exists for game programming on a new microcontroller, then it is certainly that thou shalt implement Snake.

This is [__cultsauce__]’s first foray away from Arduinoville, and although they did use one to program the ATtiny85, they learned a lot along the way.

It doesn’t take much to conjure Snake with an ’85 — mostly you need a screen to play it on (an OLED in this case), some buttons to direct the snake toward the food dot, a handful of passives, and a power source.

[__cultsauce__] started by programming the microcontroller and then tested everything on a breadboard, both of which are admirable actions. Then it was time to make this plywood and cork sandwich, which gives the point-to-point solder joints some breathing room and keeps them from getting crushed. Be sure to check it out in action after the break, and grab the files from GitHub if you want to charm your own ‘tiny Snake.

There’s a ton you can do with this miniature microcontroller, and that includes machine learning.

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