Misc Hacks

4183 Articles

Simulate A Better Termination

December 18, 2023 by 3 Comments

If you are making certain precision measurements, you know you need to terminate the connections with the right impedance, normally 50 ohms. Proper termination minimizes reflections on the line which can disturb measurements. Some instruments already have 50 ohm terminations, at least optionally. If not, you usually use little connector shells with the right resistor inside. [Joe Smith] decided to see if he could improve on the normal terminations using circuit simulation techniques. You can see a video of the work below.

In the process of testing, he also needs a resistive splitter, and, just like with the terminators, he shows you what’s going on inside. It was easy to compare since he had a scope that could independently set channels to have a 50-ohm termination or a 1 megaohm termination.

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Clockhands For Faster CPU Execution

December 9, 2023 by 15 Comments

When you design your first homebrew CPU, you probably are happy if it works and you don’t worry as much about performance. But, eventually, you’ll start trying to think about how to make things run faster. For a single CPU, the standard strategy is to execute multiple instructions at the same time. This is feasible because you can do different parts of the instructions at the same time. But like most solutions, this one comes with a new set of problems. Japanese researchers are proposing a novel way to work around some of those problems in a recent paper about a technique they call Clockhands.

Suppose you have a set of instructions like this:

LOAD A, 10
LOAD B, 20
SUB A,B
LOAD B, 30
JMPZ  DONE
INC B

If you do these one at a time, you have no problem. But if you try to execute them all together, there are a variety of problems. First, the subtract has to wait for A and B to have the proper values in them. Also, the INC B may or may not execute, and unless we know the values of A and B ahead of time (which, of course, we do here), we can’t tell until run time. But the biggest problem is the subtract has to use B before B contains 30, and the increment has to use it afterward. If everything is running together, it can be hard to keep straight.

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A Fully-Transparent Air Bubble Display

December 6, 2023 by 5 Comments

We all have good intentions when starting a new project, but then again, we all know where those lead. Such is the case with [RealCorebb]’s BBAir project, a completely transparent air bubble display. Although the plan was to spend about three months on it, the months slowly added up to a full year of tinkering.

It all started when [RealCorebb] made a subscriber counter using Minecraft campfire smoke to display the digits. Someone suggested using air to implement the next iteration, and for [RealCorebb], it was challenge accepted. After considering a syringe for each channel, a separate pump, or one pump and many solenoids, [RealCorebb] settled on solenoids to push air, and designed a PCB to reduce the amount of wire spaghetti.

Once [RealCorebb] created an acrylic enclosure and wired everything up, it was time to test it out. Everything worked, except that air was leaking from somewhere, which turned out to be the way the solenoids were installed. Then, of course, it was time to don sunglasses and write the code. We still don’t know if [RealCorebb] settled on water, glycerine, or silicone oil, but the end result is quite nice, and we’re betting on glycerine. Be sure to check out the build video after the break, which has English subtitles.

Although we’ve seen our share of bubble displays before, we often discuss bubble LEDs displays like this one.

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Inside A Rubidium Frequency Standard

December 5, 2023 by 14 Comments

We think of crystals as the gold standard of frequency generation. However, if you want real precision, you need something either better than a crystal or something that will correct for tiny errors — often called disciplining the oscillator. [W3AXL] picked up a rubidium reference oscillator on eBay at a low cost, and he shows us how it works in the video you can see below. He started with a GPS-disciplined oscillator he had built earlier and planned to convert it to discipline from the rubidium clock.

The connector looks like a D-shell connector superficially, but it has a coax connector in addition to the usual pins. The device did work on initial powerup, and using a lissajous pattern to compare the existing oscillator with the new device worked well.

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Build A Strandbeest Replica Of Your Very Own

December 3, 2023 by 1 Comment

[Theo Jansen] is famous for his giant walking Strandbeest creations. They’re elegant, impressive, and powered by nature, and their walking mechanism is a thing of beauty. If you’ve ever wanted to build your own, [Antonio Garcia] has just the guide to get you started on the smaller scale.

Unlike so many other builds today, this one features some good old fashioned craft techniques. The build uses popsicle sticks for the legs, what appear to be toothpicks for the joints, and a cardboard box for the main body. A small brushed DC motor is used for propulsion to keep things easy, which runs off a few AA batteries. It’s a gearmotor, which gives it plenty of torque to propel the walking mechanism without undue strain.

It may not be powered by nature, and it may not be taller than most humans, but it’s still got an appealing gait and it still inspires us with its design. If you want to learn more, go ahead and take a gander at [Theo Jansen’s] own designs and see what you can pick up. Video after the break.

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Adding Cellular Connectivity To The Hackaday Supercon Badge

December 2, 2023 by 1 Comment

Did you manage to make it down to Hackaday Supercon 2023? Maybe you did, and maybe you had a great time hacking away on the badge. [Dan] and ex-Hackaday alumnus [Mike Szczys] certainly did, with the guys from Golioth adding cellular connectivity to the hardware and developing a community art project.

The badge was hooked up over I2C to a Golioth Aludel Mini, which is a prototyping platform featuring a Sparkfun nRF9160 cellular modem. A custom Micropython implementation was compiled for the badge so that the badge could act as an I2C peripheral to be queried by the Aludel Mini. The sketch app on the badge was tweaked to allow the small pictures it created to be be uploaded to a cloud site called Badgecase, programmed in Rust. Amusingly, it turns out the sketch app uses a rectangular workspace, though you only see a circular section of it on the Supercon badge’s awesomely round display.

Much of the hack is happening off-board from the badge itself, but it’s a neat piece of work that shows how easy cellular connectivity is to implement these days. We’ve seen some other great feats with the Vectorscope badge, and it looked great if you happened to 3D print a case for it, too. Video after the break.

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BBC Basic Is Back In A Big Way

November 28, 2023 by 77 Comments

The BBC has a long history of teaching the world about computers. The broadcaster’s name was proudly displayed on the BBC Micro, and BBC Basic was the programming language developed especially for that computer. Now, BBC Basic is back and running on a whole mess of modern platforms.

BBC Basic for SDL 2.0 will run on Windows, MacOS, x86 Linux, and even Raspberry Pi OS, Android, and iOS. Desktop versions of the programming environment feature a BASIC editor that has syntax coloring for ease of use, along with luxury features like search and replace that weren’t always available at the dawn of the microcomputer era. Meanwhile, the smartphone versions feature a simplified interface designed to work better in a touchscreen environment.

It’s weird to see, but BBC Basic can actually do some interesting stuff given the power of modern hardware. It can address up to 256 MB of memory, and work with far more advanced graphical assets than would ever have been possible on the original BBC Micro. If you honed your programming skills on that old metal, you might be impressed with what they can achieve with BBC Basic in a new, more powerful context.

If you’re passionate about the BBC and its history with computers, we’ve talked plenty about the BBC Micro in the past, too.

[Thanks to Stephen Walters for the tip!]