3D-Printed Shredder Eats Lettuce For Breakfast

March 19, 2023 by Zoe Skyforest 15 Comments

Shredding things isn’t just good for efficiently and securely disposing of them. It’s also very fun, as well. [Joonas] of [Let’s Print] didn’t have a shredder, so set about 3D printing one of their very own.

The design apes that of the big metal trash shredders you’ve probably seen in videos all over the internet. They use a pair of counter-rotating drums with big teeth. As the drums turn, the teeth grab and pull objects into the gap between the drums, where they are duly torn apart into smaller pieces.

In this design, plastic drums are pressed into service as [Joonas] does not have a metal 3D printer. A brushed DC motor is used to drive the shredder. A large multi-stage gearbox is used to step down the motor’s output and provide plenty of torque to do the job.

The shredder gets tested with plenty of amusing garbage. Everything from old vegetables, to paper, and rock-hard old cheeseburgers are put through the machine. It does an able job in all cases, though obviously the plastic drums can’t handle the same kind of jobs as a proper metal shredder. Harder plastics and aluminium cans stall out the shredder, though. The gearbox also tends to strip gears on the tougher stuff. The basic theory is sound, but some upgrades could really make this thing shine.

Is it a device that will see a lot of practical use? Perhaps not. Is it a fun device that would be the star of your next hackerspace Show and Tell? Absolutely. Plus it might be a great way to get rid of lots of those unfinished projects that always clog up your storage areas, too! Video after the break.

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Tiny PCB PiezoPiano Plays Just One Octave

March 19, 2023 by Zoe Skyforest 11 Comments

Grand pianos are beautiful instruments, but take up altogether too much space. Upright pianos are smaller, but still fairly hefty. When it comes to the PiezoPiano, though, we suspect nobody could complain about its diminutive size. It’s a tiny thing with just one buzzy little octave for your playing pleasure.

The PiezoPiano is a single PCB device with a ATmega4809 running the show. It has eight buttons and eight piezo transducers that give you just one octave’s range on the keyboard. Truth be told, that’s only in one scale; you’re not getting the whole twelve tones of flats and sharps included. And, when we say keyboard, we really mean “tactile buttons.” You get the drift. It’s all assembled in a cute enclosure mimicking the shape of a real grand piano.

Fundamentally, it’s a cute little musical desktoy that reminds us greatly of the Stylophone. Impressively, though, those eight buzzers mean it has eight-note polyphony. That’s nothing to sniff at compared to all the monophonic synths out there. It’s also available on Tindie if you’d like to buy a kit off the shelf. Video after the break.

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Annoying Cicada Magnet Is Nonetheless Authentic

March 18, 2023 by Zoe Skyforest 17 Comments

We’ve all heard of those chirper devices that randomly make annoying noises for no other reason than sending people insane. This project from [Kousuke Saito] brings altogether more art to this idea, while still being quite annoying indeed.

The build is essentially a replica cicada. [Saito] was inspired to build the device as the sounds of the insect remind him fondly of the summer. His design consists of a 3D-printed housing that roughly approximates something like a cicada, with two wings attached to a central body. In this case, the layer lines of the 3D print actually added to the realism of the ersatz insect The housing is nicely painted to serve as an adequate simulacra to those who aren’t up on their entomology.

Inside, there’s an ATTiny 85 paired with an MP3 playback module and a small speaker. It’s charged with reproducing the noise of various cicadas. It’s setup with an ingenious mechanism to switch it on. There are magnets installed in the base which allow it to stick to metallic objects. There’s also a switch in the bottom of the device. When it magnetically attaches to a surface, that switch is depressed, and the cicada starts playing, well… cicada noises. [Saito] notes that a patent has been secured for the idea.

We’ve seen other cicada-themed projects before, astoundingly. Video after the break.

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Calibrating Thermal Cameras With Hot Patterned Objects

March 18, 2023 by Zoe Skyforest 7 Comments

Thermal cameras are great if you want to get an idea of what’s hot and what’s not. If you want to use a thermal camera for certain machine vision tasks, though, you generally need to do a geometric calibration to understand what the camera is seeing and correct for lens distortion. [Henry Zhang] has shared various methods of doing just that.

It’s all about generating a geometrically-regular thermal pattern.

To calibrate a thermal camera, first you need a thermal pattern. This is like typical test image for a camera or screen, but with temperatures instead of colors. [Henry] explains several methods for doing this. One involves using a grid of nichrome wires to create a thermal pattern for calibration purposes. Another uses discs of cold aluminium inserted into a foam board. Even a simple checkerboard can work, with the black spaces heating up more from ambient sunlight than their neighbouring white spots. [Henry] then explains the mathematical techniques used for calibrating based on these patterns.

It’s a useful primer on the topic if you’re working with thermal camera systems. We’ve looked at some other interesting machine vision topics before, too. If you’ve got any great thermal imaging tips of your own, don’t hesitate to drop us a line!

Compact Mouse Jiggler Keeps Boss Off Your Back

March 18, 2023 by Zoe Skyforest 69 Comments

The work-from-home revolution enabled many workers to break free from the shackles of the office. Some employers didn’t like the loss of perceived control though, and saddled workers with all kinds of odious spyware to monitor their computer activity. Often, this involves monitoring mouse movement to determine if workers are slacking off or not. Mouse jigglers aim to fool these systems, and the MAUS from [MAKERSUN99] is one you can build yourself.

The MAUS is not a mechanical system that moves a real-life mouse on your desk. Instead, it directly injects emulated mouse movements via USB. It runs on an ATtiny85, which is able to spit out USB HID commands with the help of the V-USB software USB implementation. Along with the microcontroller, MAUS also features a red LED and a WS2812B RGB LED for user feedback. It’s also available on Tindie if your boss has you so busy that you don’t have time to build one.

Mouse jigglers came to prominence as working from home became mainstream. However, they’ve been around for years.

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DOOM Ported To A Single LEGO Brick

March 18, 2023 by Zoe Skyforest 18 Comments

By now you’ve all seen the tiny LEGO brick with a working screen in it. The work of one [James “Ancient” Brown], it was truly a masterpiece of miniaturization and creativity. Since then, [James] hasn’t stopped innovating. Now, he’s demoing a playable version of DOOM running on a single plastic brick.

We’ve covered the construction of these astounding screen bricks before. Long story short, [James] designed a tiny PCB that hosts an RP2040 microcontroller which is then hooked up to a tiny OLED screen. The components are placed in a silicone mold, which is then filled with transparent resin to form the brick. The screen is then powered via contacts in the bottom, much like older-style LEGO motors.

Early experiments involved running various graphics to emulate a spaceship dashboard, but [James] has now gone much further. He’s implemented RP2040-doom to run the game. It uses tilt controls thanks to an accelerometer, combined with capacitive touch controls for shooting. The monochrome OLED is driven very fast with a special library of [James’] own creation to create three levels of grayscale to make the game actually visible and (just barely) playable.

It’s a hack, of course, and the controls are far from perfect. Nobody’s speed-running E1M1 on [James’s] LEGO brick, to be sure. Perchance. With that said, it’s still a glorious piece of work nonetheless. Just imagine, sitting with friends, and announcing you’re going to play some DOOM — only to pluck a piece of LEGO out of your pocket and start blasting away at demons.

Just because [James] doesn’t know when to quit, we’re going to lay down the gauntlet. Let’s get network play happening on these things, yeah?
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The Blue Soup Saga Is One Beefy Mystery

March 17, 2023 by Zoe Skyforest 38 Comments

Beef soup! You’d normally expect it to be somewhere from reddish-brown to grey, depending on how well it was cooked and prepared. However, strangely, an assistant professor found the beef soup in their fridge had mysteriously turned blue. That spawned an investigation into the cause which is still ongoing.

[Dr. Elinne Becket] has earned her stripes in microbiology, but the blue soup astounded her. Despite her years of experience, she was unable to guess at the process or a source of contamination that could turn the soup blue. Indeed, very few natural foods are blue at all. Even blueberries themselves are more of a purple color. The case sparked enough interest that [Elinne] went back to the trash to collect photos and sample for research at the request of others.

Thus far, metagenomic DNA analysis is ongoing and samples of the soup have been cultivated in petri dishes. Early analysis shows that some of the microbes form iridescent colonies, Another researcher is trying to determine if the bugs from the soup can make blue color appear on soft cheese. There’s some suspicion that a bacteria known as pseudomonas aeruginosa could be the cause of the blue color, but that presents its own problems. P. aeruginosa is classified as a Biosafety Level 2 pathogen which would require some researchers to abandon work on the project for safety reasons.

The jury’s still out on this microbiological mystery. If you’ve got some ideas on what could be going on, let us know in the comments!