Messing With JPEGs In A Text Editor Is Fun And Glitchy

If you’re looking to edit an image, you might open it in Photoshop, GIMP, or even Paint Shop Pro if you’re stuck in 2005. But who needs it — [Patrick Gillespie] explores what can be done when editing a JPEG on a raw, textual level instead.

As the video explains, you generally can’t simply throw a JPEG into Notepad and start making changes all willy nilly. That’s because it’s very easy to wreck key pieces of the image format that are required to render it as an image. Particularly because Notepad likes to sanitize things like line endings which completely mess up the structure of the file. Instead, you’re best off using a binary editor that will only change specific bytes in the image when you tell it to. Do this, and you can glitch out an image in all kinds of fun digital ways… or ruin it completely. Your choice!

If you’d like to tinker around with this practice, [Patrick] has made a tool for just that purpose. Jump over to the website, load the image of your choice, and play with it to your heart’s content.

This practice is often referred to as “datamoshing,” which is a very cool word, or “databending,” which isn’t nearly as good. We’ve explored other file-format hacks before, too, like a single file that can be opened six different ways. Video after the break.

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Close-Up Look Reveals That Raindrops Are More Erosive Than Assumed

Whenever it rains, people generally don’t look too closely at what the drops do exactly when they hit a surface. We generally assume that stuff will get wet and depending on the slope of the surface it’ll run off downhill at some point, probably in a nice, neat flow. Of course, reality doesn’t work that way, as Swiss researchers recently found when they pointed high-speed cameras at simulated raindrops. Their findings were published recently in Applied Physical Sciences, which is sadly paywalled, but the summary article over at phys.org provides some details, including a video.

The researchers set up a 1.2 meter long dry silicate sand surface with a 30° slope on which the drops were released. In the top image you can see two stills of the result, with the full video showing the drops turning into either peanut- or doughnut-shaped forms that gathered significant amounts of sand grains. These grains mix with the water, allowing a single drop to erode significant amounts of material from a slope, more than was previously assumed in existing soil erosion models.

Beyond erosion, these findings also offer insights for similar dynamics in other fields, all thanks to a group of researchers who got curious during a rainy walk and decided to take a closer look.

A round, 3D-printed motor housing is shown, with one flattened side holding a fan mount. A circular plate is mounted above the face of the housing, and a cord runs around it and pulleys on the side of the housing.

Tying Up Loose Ends On A Rope-based Robot Actuator

One of the perennial challenges of building robots is minimizing the size and weight of drive systems while preserving power. One established way to do this, at least on robots with joints, is to fit each joint with a quasi-direct-drive motor integrating a brushless motor and gearbox in one device. [The 5439 Workshop] wanted to take this approach with his own robot project, but since commercial drives were beyond his budget, he designed his own powerful, printable actuator.

The motor reducing mechanism was the biggest challenge: most quasi-direct drives use a planetary gearbox, but this would have been difficult to 3D-print without either serious backlash or limited torque. A cycloidal drive was an option, but previous printable cycloidal drives seemed to have low efficiency, and they didn’t want to work with a strain-wave gearing. Instead, he decided to use a rope drive (this seems to be another name for a kind of Capstan drive), which doesn’t require particularly strong materials or high precision. These normally use a rope wound around two side-by-side drums, which are difficult to integrate into a compact actuator, but he solved the issue by putting the drums in-line with the motor, with two pairs of pulleys guiding the rope between them in a “C” shaped path.

The actual motor is a hand-wound stator inside a 3D-printed rotor with magnets epoxied into it. The printed rotor proved problematic when the attraction between the rotor and magnets caused it to flex and scrape against the housing, and it eventually had to be reinforced with some thin metal sheets. After fixing this, it reached five Newton-meters of torque at one amp and nine Newton-meters at five amps. The diminishing returns seem to be because the 3D-printed pulley wheels broke under higher torque, which should be easy to fix in the future.

This looks like a promising design, but if you don’t need the output shaft inline with the motors, it’s probably easier to build a simple Capstan drive, the mathematics of which we’ve covered before. Both makers we’ve previously seen build Capstan drives used them to make robot dogs, which says something for their speed and responsiveness.

Putting The M In A UNI-T MSO

[Kerry Wong] points out that the Uni-T MSO oscilloscopes have a logic analyzer built in — that’s the MSO, or Mixed Signal Oscilloscope, part — but you have to add the probes. He shows you how it works in a recent video below.

He’s looked at the scope’s analog capabilities before and was not unimpressed. The probes aren’t inexpensive, but they do unlock the mixed signal capabilities of the instrument.

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Commodore Disk Drive Becomes General Purpose Computer

The Commodore 1541 was built to do one job—to save and load data from 5.25″ diskettes. [Commodore History] decided to see whether the drive could be put to other purposes, though. Namely, operating as a standalone computer in its own right!

It might sound silly, but there’s a very obvious inspiration behind this hack. It’s all because the Commodore 1541 disk drive contains a MOS 6502 CPU, along with some RAM, ROM, and other necessary supporting hardware. As you might remember, that’s the very same CPU that powers the Commodore 64 itself, along with a wide range of other 1980s machines. With a bit of work, that CPU can indeed be made to act like a general purpose computer instead of a single-purpose disk controller.

[Commodore History] compares the 1541 to the Commodore VIC-20, noting that the disk drive has a very similar configuration, but less than half the RAM. The video then explains how the drive can be reconfigured to run like the even-simpler MOS Technology KIM-1 — a very primitive but well-known 8-bit machine. What’s wild is that this can be achieved with no hardware modifications. It’s not just a thought exercise, either. We get a full “Hello World!” example running in both BASIC and machine code to demonstrate that it really works.

Code is on GitHub for the curious. We’ve featured hacks with the chunky Commodore 1541 before, too.

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Hands On WIth The Raspberry Pi Compute Module Zero

We are all familiar enough by now with the succession of boards that have come from Raspberry Pi in Cambridge over the years, and when a new one comes out we’ve got a pretty good idea what to expect. The “classic” Pi model B+ form factor has been copied widely by other manufacturers as has their current Compute Module. If you buy the real Raspberry Pi you know you’ll get a solid board with exceptionally good software support.

Every now and then though, they surprise us, with a board that follows a completely different path, which brings us to the one on our bench today. The Compute Module Zero packs the same quad-core RP3 system-on-chip (SoC) and Wi-Fi module as the Pi Zero 2 W with 512 MB of SDRAM onto a tiny 39 mm by 33 mm postage-stamp module. It’s a Pi, but not as you know it, so what is it useful for? Continue reading “Hands On WIth The Raspberry Pi Compute Module Zero”

Illustration of Chladni's technique for producing his figures, from John Tyndall's Sound (1869)

Popular Science Experiments In Sound During The 19th-Century

Check one, two; check one, two; is this thing on? Over on The Public Domain Review [Lucas Thompson] takes us for a spin through sound, as it was in Britain around and through the 1800s.

The article begins by introducing the Father of Acoustics, German physicist Ernst Chladni. After placing grains of sand on a thin metal plate and drawing a violin bow along one edge Chladni figures appear, making manifest that which previously could only be heard, that is, sound waves.

It’s fun to think that it wasn’t so long ago that the physics of sound was avant-garde. Middle class Victorian society was encouraged to reproduce cutting edge experiments with equipment in their own homes, participating in a popular science which was at the same time part entertainment and part instruction, for young and old alike. Throughout the rest of his article [Lucas] lists a number of popular science books from the period and talks a little about what was to be found within.

See the video below the break for a demonstration of Chladni figures from The Royal Institution. Of course the present state of the art regarding sonics is well advanced as compared with that of the 19th century. If you’re interested to know more check out Building A Wall-Mounted Sound Visualizer and Seeing Sound For Under $200.

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