PNG Image Decoding Library Does It With Minimal RAM

July 17, 2021 by Donald Papp 11 Comments

Want to display a PNG file on a display attached to an Arduino or other microcontroller board? You’ll want to look at [Larry Bank]’s PNGdec, the Arduino-friendly PNG decoder library which makes it much easier to work with PNG files on your chosen microcontroller.

The PNG image format supports useful features like lossless compression, and was generally developed as an improved (and non-patented) alternative to GIF files. So far so great, but it turns out that decoding PNG files on a microcontroller is a challenge due to the limited amount of memory compared to desktop machines. When the PNG specification was developed in the 90s, computers easily had megabytes of memory to work with, but microcontrollers tend to have memory measured in kilobytes, and lack high-level memory management. [Larry]’s library addresses these issues.

PNGdec is self-contained and free from external dependencies, and also has some features to make converting pixel formats for different display types easy. It will run on any microcontroller that can spare at least 48 K of RAM, so if that sounds useful then check out the GitHub repository for code and examples.

We’ve seen [Larry]’s wonderful work before on optimizing GIF playback as well as rapid JPEG decoding, and these libraries have increasing relevance as hobbyists continue to see small LCD and OLED-based displays become ever more accessible and affordable.

[PNG logo: PNG Home Site]

CNC Saves Water Cooling Setup

July 17, 2021 by Al Williams 9 Comments

A classic problem. You have a new CPU and a 15-year old water cooling system. Of course, the bracket doesn’t fit. Time to buy a new cooler? Not if you are [der8auer]. You design a new bracket and mill it out of aluminum.

Honestly, it might seem overkill, but it makes sense. After all, no matter how new the CPU is, using water to cool it still works the same way, in principle.

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Reinvented Retro Contest Winners Announced

July 17, 2021 by Kristina Panos 7 Comments

Good news, everyone! The results of the Reinvented Retro contest are in, and the creators of these three groovy projects have each won a $200 online shopping spree to Digi-Key. We asked you to gaze deeply into your stuff piles and come up with a way to modernize a cool, old piece of hardware, and we left it up to you to decide how cool and how old.

No matter your personal vintage, you have probably used or even built an educational computer like [Michael Wessel]’s next-generation Microtronic. This is a re-creation of an early 1980s West German 4-bit microprocessor trainer called the Busch 2090 Microtronic Computer System. You may have never heard of it, but [Michael] swears it’s one of the best ever made. Years ago, [Michael] made a talking Arduino-based Microtronic emulator and has grown the concept into a prize-winning system that uses an ATMega2560 Pro Mini and a Nokia 5110 display. As a bonus, it doubles as a cassette interface emulator that plugs into the 2090’s expansion port. Take some time to dive into the YouTube videos or go straight for the gerbers and make your own.

EBTKS – a tape drive replacement for HP Series80 computers

Resurrected MK-52 calculator now does things it could never have dreamed of

Retrocomputing fans will love EBTKS, a project that seeks to circumvent the disintegrating tape drives in HP85A and other early 1980s HP computers by emulating them and delivering 20,000 virtual tapes via SD card. The project began as a solid state replacement using a Teensy and an ESP32, but [Philip] and the team realized they could do a whole lot more than that. The full list of features includes 70 new keywords and both disk and tape drive emulation. Everything is explained in detail on the project’s main documentation site, where you’ll also find a handy user guide.

If you have a soft spot for old Soviet gear, check out [ptrav]’s MK-52 Resurrection. [ptrav] took an early 90s-vintage calculator with a busted vacuum fluorescent display and breathed new life into it with an ESP32 and a 320×240 TFT screen. The point isn’t to merely resurrect the MK-52, but rather to create a phoenix of programmable Soviet calculating power that rises from the ashes and realizes its hardware unleashed potential. As part of the software development path, [ptrav] also built a fully-functional simulator in C# which you can check out on GitHub.

A Most Honorable Mention

It’s always so difficult to pick winners from among all the amazing projects we see. For this contest, we’ve chosen [Michael Gardi]’s WDC-1 — aka the Paperclip Computer — for an honorable mention. And that means more than just a published pat on the back — [Michael] has won a $25 gift card for Tindie. Way to go, [Michael]!

This WDC-1 is a bit of an inverse take on the reinvented retro concept. Instead of new tech in an old box, [Michael] employed modern PCB fabrication and 3D printing to house the upgraded homebrew guts of this 50+ year-old computer design.

Congratulations to all the winners, and a big thank you to all 138 entrants for your faux nostalgia-inspiring builds. Take some time this weekend to check them out, and get your alternate reality on.

Tales From The Global Chip Shortage: Smoothieboard

July 17, 2021 by Stephen Ogier 27 Comments

The semiconductor shortage sparked by the pandemic is showing no signs of slowing down. Although auto manufacturers were some of the first affected, the shortage has now spread and is impacting all sorts of projects, including the Smoothieboard open-source CNC controllers.

[Chris Cecil] walks through the production woes they’ve had over the last few months. It began this spring with a batch of the V1.1 boards. The prices of some of their chips started jumping, and then they were informed that the microcontroller that serves as the brains of the Smoothieboard was only available for five times the old price. In the end, they placed a smaller order, and V1.1 Smoothieboards will likely be scarce until the microcontroller’s price returns to normal.

Getting V2 of the boards into production has been even more difficult. Just weeks before the final prototype, it was discovered that the LPC4330 microcontroller the V2 was built around was also sold out worldwide. With the shortage in mind, a hole was left in the layout of the final version of V2 so that they could finish the design around whatever microcontroller they were able to get. In the end, they were able to lock down a supply of STM32H745 controllers, which are actually substantially more capable than the original device.

If you’re interested in the origins of the chip shortage, this article from January is a good place to start. This isn’t the first time parts shortages have wreaked havoc on the world of electronics—does anyone remember the global resistor shortage of ’18?

Open Source Is Choice

July 17, 2021 by Elliot Williams 79 Comments

If you haven’t been following along with the licensing kerfuffle surrounding the open-source Audacity audio editing software, take a sec to read Tom Nardi’s piece and get up to speed. The short version is that a for-profit company has bought the trademark and the software, has announced plans to introduce telemetry where there was none, made ominous changes to the privacy policy that preclude people under the age of consent from using the software, and requested that all previous developers acquiesce to a change in the open-source license under which it is published. All the while, the company, Muse, says that it will keep the software open, and has walked back and forth on the telemetry issue.

What will happen to “Audacity”? Who knows. But also, who cares? At least one fork of the codebase has been made, with the telemetry removed and the old open licenses in place. The nicest thing about open source is that I don’t care one bit if my software is named Audacity or Tenacity, and this is software I use every week for production of our podcast. But because I haven’t paid any license fees, it costs me absolutely nothing to download the same software, minus some anti-features, under a different name. If the development community moves over to Tenacity, it’ll all be fine.

Tom thinks that the Audacity brand is too big to fail, and that Muse will have a hit on their hands. Especially if they start implementing new, must-have features, they could justify whatever plans they have in store, even if they’re only available as a “freemium” Audacity Pro, with telemetry, under a more restrictive license. When that does happen, I’ll have to make the choice between those features and the costs, but I won’t be left out in the cold as long as the Tenacity fork gets enough eyes on it. So that’s just more choice for the end-user, right? That’s cool.

Compare this with closed source software. There, when the owner makes an unpopular decision, you simply have to take it or make the leap to an entirely different software package. This can be costly if you’ve gotten good at using that software, and between licenses and learning, there’s a lot of disincentive to switching. Not so in this case. If I don’t want to be tracked while editing audio offline, I don’t have to be. Woot.

The elephant in the room is of course the development and debugging community, and it’s way too early to be making predictions there. However, the same rules apply for devs and users: switching between two virtually identical codebases is as easy as git remote add origin or apt get install tenacity. (Unpaid) developers are free to choose among forks because they like the terms and conditions, because one group of people is more pleasant to work with, or because they like the color of one logo more than the other. Users are just as free to choose.

Time will tell if Audacity ends up like the zombie OpenOffice, which is downloaded in spite of the much superior LibreOffice just because of the former’s name recognition. I know this split riles some people up, especially in the LibreOffice development community, and it does seem unfair that the better software somehow enjoys less reputation. But for those of us in the know, it’s just more choice. And that’s good, right?

Soviet Scientific Calculator Gives Up Its Cold War-Era Secrets

July 17, 2021 by Dan Maloney 17 Comments

Say what you want about Soviet technology, but you’ve got to admit there was a certain style to Cold War-era electronics. Things were perhaps not as streamlined and sleek as their Western equivalents, but then again, just look at the Nixie tube craze to see where collectors and enthusiasts stand on that comparison.

One particularly interesting artifact from the later part of that era was the lovely Elektronika MK-52 “microcalculator”. [Paul Hoets] has done a careful but thorough teardown of a fine example of this late-80s machine. The programmable calculator was obviously geared toward scientific and engineering users, but [Paul] relates how later versions of it were also used by the financial community to root out banking fraud and even had built-in cryptographic functions, which made encrypting text easy.

[Paul] has put together a video of the teardown, detailing the mostly through-hole construction and the interesting use of a daughter-board, which appears to hold the high-voltage section needed to drive the 11-character VFD tube. The calculator appears to be very well cared for, and once reassembled looks like it would be up for another ride on a Soyuz, where once it served as a backup for landing calculations.

We love the look of this machine and appreciate [Paul]’s teardown and analysis. But you say that the Cyrillic keyboard has you stumped and you need a bilingual version of the MK-52? That’s not a problem.

Finding Fractals In The 1930’s

July 17, 2021 by Matthew Carlson 22 Comments

The mesmerizing properties of fractals are surprising as their visual complexity often arises from simple equations. [CodeParade] set out to show how simple a fractal is by creating them using technology from the 1930s. The basic idea is based on projectors and cameras, which were both readily available and widely used in television (CRT projectors were in theaters by 1938, though they weren’t in color until the 1950s).

By projecting two overlapping images on the wall, pointing a camera at the resulting image, and then feeding it back into the projectors, you get some beautiful fractals. [CodeParade] doesn’t have a projector, much less two. So he did what any hacker might do and came up with a clever workaround. He made a simple app that “projects” onto his monitor and all he has to do is point an external webcam at the screen. The resulting analog fractals are quite beautiful and tactile. Rather than tweaking a variable and recompiling, you simply just add a finger or move the camera to introduce new noise that quickly becomes signal.

Better yet, there’s a web version that you can play around with right now. For more fractals implemented in hardware rather than software, there’s this FPGA with a VHDL Mandelbrot set we covered.

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