Day: September 27, 2023

Proper Video, From An ESP32

September 27, 2023 by 19 Comments

Back in the day a miniature television, probably on a wristwatch, was the stuff of science fiction. Now, it’s something which can be done with a commodity microcontroller, as [Atomic14] shows us with the ESP32-TV that plays both video and sound. Even with modern silicon it’s still somewhat pushing the envelope.

As he explains in the video below the break, not all formats are simple enough to be decoded on the fly by a microcontroller. But he finds an AVI file to be within its capabilities which can be created with a bit of ffmpeg wizardry. The board is a fairly standard ESP32 device with an I2C bus, and the video stream isn’t too fast for this meager interface. You’ll maybe recognize the Muppets clip, but it’s possible that the early-80s BBC comedy staple The Young Ones might have passed you by if you’re not British.

We think this code is likely to be of use in quite a few projects, and it would be great to see it further refined. Small video players for not a lot of money can never be a bad thing.

Previous ESP32 video projects which have appeared on these pages have been more likely to involve driving a display directly.

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Investigating The Fourth Passive Component

September 27, 2023 by 45 Comments

When first learning about and building electronic circuits, the first things all of us come across are passive components such as resistors, capacitors, and inductors. These have easily-understandable properties and are used in nearly all circuits in some way or another. Eventually we’ll move on to learning about active components like transistors, but there’s a fourth passive circuit component that’s almost never encountered. Known as the memristor, this mysterious device is not quite as intuitive as the other three, so [Andrew] created an Arduino shield to investigate their properties.

Memristors relate electric charge and magnetic flux linkage, which means that their resistance changes based on the current that passes through them. As their name implies, this means they have memory, and retain their properties even after power is removed. [Andrew] is testing three different memristors, composed of tungsten, carbon, and chromium, using this specialized test set. The rig is based on an Arduino Uno and has a few circuit components that can be used as references and generates data on the behavior of the memristors under various situations.

The memristors used here do exhibit expected behavior when driven with positive voltage signals, but did exhibit a large amount of variability when voltage was applied in a negative direction. [Andrew] speculates that using these devices for storage would be difficult and would likely require fairly bespoke applications for each type. But as the applications for these seemingly bizarre circuit components increase, we expect them to improve much like any other passive component.

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Explore Linux Space Time

September 27, 2023 by 7 Comments

If you’ve ever wondered how much memory a process uses, you’ve probably used a form of task manager or system monitor. System monitors can be useful to identify resource hogs, but are often less versatile if you want more details about just one process. If you’ve ever faced this problem, then [Fabien Sanglard]’s Space-Time explorer is for you!

The wonderfully punny Space-Time tool records physical memory usage, time spent in user space vs. kernel space and even threads and subprocesses created. These words may not mean much to some readers, so let’s quickly go over them: Physical memory usage is the actual amount of RAM given (not always the same as requested). The kernel (which lives in kernel space) is the supervisor to all processes on a computer. In contrast, every process lives in it’s own “user space”, a way of protecting the kernel. Finally, a subprocess (or “child process”) is simply a process started by another process (the “parent”). Continue reading “Explore Linux Space Time” →

Testing Oxide Etchants For The Home Semiconductor Fab

September 27, 2023 by 3 Comments

Building circuits on a silicon chip is a bit like a game of Tetris — you have to lay down layer after layer of different materials while lining up holes in the existing layers with blocks of the correct shape on new layers. Of course, Tetris generally doesn’t require you to use insanely high temperatures and spectacularly toxic chemicals to play. Or maybe it does; we haven’t played the game in a while, so they might have nerfed things.

Luckily, [ProjectsInFlight] doesn’t treat his efforts to build semiconductors at home like a game — in fact, the first half of his video on etching oxide layers on silicon chips is devoted to the dangers of hydrofluoric acid. As it turns out, despite the fact that HF can dissolve your skin, sear your lungs, and stop your heart, as long as you use a dilute solution of the stuff and take proper precautions, you should be pretty safe around it. This makes sense, since HF is present in small amounts in all manner of consumer products, many of which are methodically tested in search of a practical way to remove oxides from silicon, which [ProjectsInFlight] has spent so much effort recently to learn how to deposit. But such is the ironic lot of a chip maker.

Three products were tested — rust remover, glass etching cream, and a dental porcelain etching gel — against a 300 nm silicon dioxide layer. Etch speed varied widely, from rust remover’s 10 nm/min to glass etching cream’s blazing 240 nm/min — we wonder if that could be moderated by thinning the cream out with a bit of water. Each solution had pros and cons; the liquid rust remover was cheap easy to handle and clean up, while the dental etching gel was extremely easy to deposit but pretty expensive.

The good news was that everything worked, and each performed differently enough that [ProjectsInFlight] now has a range of tools to choose from. We’re looking forward to seeing what’s next — looks like it’ll be masking techniques.

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Hackaday Prize 2023: An Anti-Tremor Handle, With No Electronics

September 27, 2023 by 16 Comments

Many of us will have seen the various active assistive devices which have appeared over the last few years to help people with a hand tremor. Probably the best known was a fork with a set of servos and an accelerometer, that kept the end of the utensil steady despite the owner’s hand movements. It’s a field which has the potential to help many people, but it’s undeniable that such technology comes with a cost.

What if the same effect could be achieved passively, without all those electronics? It’s something [Jacob] is investigating with his mechanical anti-tremor cup handle. It’s a university project completed as part of his studies so it’s very much a work-in-progress which if we’re being fair isn’t quite there yet, but we think the potential in this idea of bringing a useful assistive device at least bears further attention.

The write-up is available as a Norwegian PDF file so takes a little bit of Google Translate cut and pasting for an Anglophone. Sadly due to what must be report format requirements set by the university it’s long on procedure and shorter on engineering calculations than we’d like, but there’s an attempt to calculate the properties of the helical springs in each of the joints to match the likely forces. Our intuition is that the design as shown would require significantly more mass on the end of it than that of the mug and beverage alone to achieve some form of stability, but despite that as we said it’s an interesting enough idea that it deserves more thought.

Hand tremor assistive devices have appeared more than once on these pages before, here’s one for soldering that enlists the aid of a camera gimbal.

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You’ve Got Mail: Faster And Faster We Go

September 27, 2023 by 9 Comments

When we last left the post office, they had implemented OCR to read even the sloppiest of handwriting. And to augment today’s 99% accuracy rate, there’s a center full of humans who can decipher the rest of those messy addresses with speed and aplomb. Before that, we took a look at many of the machines that make up the automated side of the post office’s movements. But what was being done to improve the customer experience during all of this time?

Quite a bit, as it turns out. In this installment, we’ll take a look at the development of vending machines and programs like Speed Mail, Missile Mail, and V-Mail (no, not voicemail!) as they relate to enhanced customer service over the years.

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String Art Build Uses CNC To Make Stringy Art

September 27, 2023 by 12 Comments

String art is as old as, well, string and something to hang it from. But, like most things, it gets more enjoyable when you involve a CNC. [Paul MH] went the whole hog with this build, creating a CNC string art builder that could handle the whole process, from placing the nails to running the string.

It’s an impressive build: you feed in an image, and the system calculates the location of the pins and the path that the string will need to follow. It then puts the nails into the board, pushes them in, and, with a custom attachment for the CNC, runs the string to create the art.

Of course, the path to this was filled with prototypes, failures, and dead ends. [Paul] has laid these out pretty well in the video for the project, which he just released. In this, problems like detecting when the nails are picked up and placed are detailed, and the prototypes and Rube Goldberg solutions that [Paul] came up with are covered.

Like all great projects, it is still a work in progress, but [Paul] has made some impressive progress, although he hasn’t posted the code and models for his custom parts yet. We’ve featured several string art builds, from polar platforms to fully formed commercial-grade builds that print your work for you.

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