Roboticizing An Etch-a-Sketch

April 19, 2024 by Lewin Day 7 Comments

The Etch-a-Sketch was a popular toy, but a polarizing one. You were either one of those kids that had the knack, or one of the kids that didn’t. [Micah] was pretty firmly in the latter group, so decided to roboticize the Etch-a-Sketch so a computer could draw for him instead.

The build uses a pair of stepper motors attached to the Etch-a-Sketch’s knobs via 3D-printed adapters. It took [Micah] a few revisions to get the right design and the right motors for the job, but it all came together. A Raspberry Pi is charged with driving the motors to draw the desired picture.

Beyond the mechanics, [Micah] also does a great job of explaining the challenges around drawing and the drive software. Namely, the Etch-a-Sketch has a major limitation in that there’s no way to move the stylus without drawing a line. He accounts for this in his code for converting and drawing images.

The robot draws slowly but surely. The final result is incredibly impressive, and far exceeds what most of us could achieve on by hand. We’ve seen some similar builds in the past, too. Video after the break.

Continue reading “Roboticizing An Etch-a-Sketch” →

Crank-Powered Train Uses No Batteries Or Plugs

April 12, 2024 by Kristina Panos 5 Comments

The prolific [Peter Waldraff] is at back it with another gorgeous micro train layout. This time, there are no plugs and no batteries. And although it’s crank-powered, it can run on its own with the flip of a switch. How? With a supercapacitor, of course.

The crank handle is connected a 50 RPM motor that acts as a generator, producing the voltage necessary to both power the train and charge up the supercapacitor. As you’ll see in the video below, [Peter] only has to move the train back and forth about two or three times before he’s able to flip the switch and watch it run between the gem mine and the cliff by itself.

The supercapacitor also lights up the gem mine to show off the toiling dwarfs, and there’s a couple of reed switches at either end of the track and a relay that handles the auto-reverse capability. Be sure to stick around to the second half of the video where [Peter] shows how he built this entire thing — the box, the layout, and the circuit.

Want to see more of [Peter]’s trains and other work? Here you go.

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Get Today’s Forecast In Classic 90s Weather Channel Style

April 10, 2024 by Dan Maloney 9 Comments

Remember when The Weather Channel actually had weather? It’s been a while, but we sure remember what a boon Local on the 8’s was when getting ready for the day. Not having to wait for the low-information national forecast on the morning shows or putting up with the antics of [Willard Scott] or [Al Roker] was just icing on the cake.

Recreating the retro look and feel of the Weather Channel experience is what this 1990s-style weather feed is all about, and we have to say that [Mitchell Scott] knocked it out of the park. Luckily, a lot of the heavy lifting was done already thanks to the WeatherStar 4000+ emulator project, which renders forecasts using online weather APIs in the distinctive retro graphics The Weather Channel used back in the day. He combined the graphics with the original smooth jazz soundtracks that TWC used back then; they’re online, because of course they are.

To really sell the look, [Mitchell] tracked down a period-correct Zenith TV with a 9″ CRT to display the feed from a Raspberry Pi 4’s composite video output. Why such a small screen? Easy. [Mitchell] wanted it on a shelf behind him to be visible during videoconferences. It’s a bit of a weird flex, but we respect it. Getting the composite video output working was a bit of a chore, as was tricking the TV into starting up on channel 14 so the feed is instantly visible.

The nostalgia is strong with this one, especially for weather geeks. For a more in-depth look at how The Weather Channel brought those local forecasts to cable, make sure you check out how the WeatherStar box was reverse-engineered.

Thanks to [USA-RedDragon] for the tip.

Vibratory Rock Tumbler Bounces On Printed Spring

April 4, 2024 by Tom Nardi 26 Comments

If you’re reading Hackaday, there’s a good chance you had a rock tumbler in your younger days. Hell, we’d put odds on a few of you having one rumbling away in the background as you read this. They’re relatively simple contraptions, and a common enough DIY project. But even still, this largely 3D printed rock tumbler from [Fraens] is unique enough to stand out.

To make a basic rock tumbler, all you really need to do is rotate a cylindrical chamber and let physics do its thing. Such contraptions are known as, unsurprisingly, rotary rock tumblers. But what [Fraens] has put together here is a vibratory tumbler, which…well, it vibrates. If this was Rockaday we might go farther down this particular rabbit hole and explain the pros and cons of each machine, but the short version is that vibratory tumblers are more mechanically complex and are generally better suited to fine finish work than rotary tumblers which take a brute force approach that tends to round off the rocks.

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A Stirling Engine From Minimal Parts

March 28, 2024 by Jenny List 5 Comments

The model Stirling engine is a staple of novelty catalogues, and we daresay that were it not for their high price there might be more than one Hackaday reader or writer who might own one. All is not lost though, because [jirka.luftner] has posted one on Instructables which eschews the fancy machined brass of the commercial models and achieves the same result with an array of salvaged parts.

The main cylinder is a former apple drops tin with a cardboard displacer, and the CD/DVD flywheel is mounted on either a 3D printed or cut out frame with the secondary cylinder cut into it. A diaphragm for the secondary cylinder is taken from a rubber glove, and the cranks come courtesy of bent wire.

A slight mystery of this design is that it appears not to have a regenerator, or heat store. This usually lies in the path between the two cylinders to improve efficiency by taking the heat from the air as it passes in-between the two, and returning it when it goes the other way. We’re guessing that on an engine this small it’s the tin itself which performs this function. Either way this is a neat little engine that shouldn’t break the bank.

If this has whetted your appetite, you’ll be pleased to hear it’s not the first Stirling engine we’ve seen made from what was lying around.

Build Yourself A Vacuum Tube VU Meter

March 22, 2024 by Lewin Day 5 Comments

Volume unit (VU) meters are cool — it’s an undeniable fact. For some reason, humans just dig lights that flash along with sounds. You can build a VU meter using LEDs, or bulbs if you’re trapped in 1972. Or, you could use special vacuum tubes. [mircemk] did just that in their latest VU meter project.

The 6E2 vacuum tube is the part for the job in this case. You might think a specialist tube like this is expensive, but they can be had for just a few dollars from online retailers. They were often used as tuning indicators, but here, they’re used as a responsive VU meter instead. However, instead of a single bar going up and down, you get a pair of bars that raise to meet in the middle.

[mircemk] explains all the circuitry required to drive the tubes, and how to hook them up to create a two-channel stereo VU meter. The final circuit largely relies on a transistor, a diode, some passive components, and a DC-DC boost supply to generate 250 V for the tubes.

The final result looks pretty neat, particularly as it’s built into an old-school blue project box. We’ve seen similar projects from [mircemk] before, too. Continue reading “Build Yourself A Vacuum Tube VU Meter” →

Modern Microcontroller Boosts Classic Logic Analyzer To New Heights

March 19, 2024 by Lewin Day 5 Comments

[Ted Fried] recently found a beautiful HP 1600A/1607A logic analyzer set. State of the art in 1975, it looks like glorious Space Age equipment today. He decided to hook it up some modern gear to put it through its paces.

Wanting to give the equipment a proper shakedown, he enlisted a Teensy 4.1 to spit a deluge of logic at the HP unit. The microcontroller was tasked with generating 32 data signals along with two clock outputs to give the analyzer plenty to analyze. The HP 1600A handled this no problem, so [Ted] kept tinkering.

His next feat was to explore the addressable “MAP” function of the unit, which allowed writing to the 64×64 pixel display. The Teensy 4.1 was easily able to send images to the display, but [Ted] isn’t stopping there. He’s got plans to do the usual thing and get Bad Apple going on the hardware.

Getting a logic analyzer to analyze logic isn’t much of a hack, sure. But it’s instructive of how to approach working with such hardware. If you want to spit a bunch of logic out fast, a Teensy 4.1 is a great choice because it’s got a ton of IO and a ton of clock cycles to tickle it with.

We enjoyed seeing this old piece of hardware light up the phosphors once more. If you’ve got your own projects going on with classic bits of HP test gear, don’t hesitate to let us know!