Tracking The ISS Made Easy

April 7, 2025 by Elliot Williams 3 Comments

If you made something blink, and now it’s time for you to make something move, something like a point-to-a-satellite tracker is a great idea. [Farid Rener] made this moving arrow that always points at the ISS, and documented it nicely to boot.

And there’s a little bit of everything here, from orbital mechanics and fetching the two-line elements (TLE) from the web, to writing the code to translate that into the tabletop machine’s coordinate system. It looks like [Farid] hadn’t done much 3D CAD before, so he got a chance to stretch those muscles too. Finally, it served as an introduction to resource-constrained programming: “This was the first time I’ve had to think about the size of a compiled binary – the most frustrating part was figuring out that using a C++ stringstream was adding too much code to my binary.”

[Farid] is learning a lot here, and you might too. For instance, using pencil lead (graphite) as a lubricant on sliding 3D-printed parts is new to us, but makes sense. We’ll have to try that out.

And while this is a simple desktop tracker, with a lot more mechanical design, the same basics could be put to real use for pointing a receiver dish. Of course, who says you need fancy motors and computers to point a satellite dish anyway? If you work on your arm muscles a bit, you could become the satellite pointer.

Ben Eater Vs. Microsoft BASIC

April 5, 2025 by Elliot Williams 12 Comments

[Ben Eater]’s breadboard 6502 computer is no stranger to these parts, so it was a bit of a surprise that when [Mark] wrote in asking us if we’d covered [Ben]’s getting MS BASIC running on the breadboard, that our answer was “no”. Well, that changes today!

This is a three-part video series, documenting how [Ben Eater] ports a 1977 version of MS BASIC to his 6502-based computer. The first video is all about just getting the BASIC up and working. It’s full of detail about how MS BASIC adapts to different architectures on the inside, and [Ben] essentially defines his own along the way.

Once he has BASIC working, the next two videos are about making it work not just with the serial terminal that he has attached, but also with the LCD display peripheral he has plugged into the breadboard. BASIC fans will not be surprised to see that it’s all about using POKE. But that ends up being to slow, so he extends it out with his own LCDPRINT command written in assembly.

Now that he can write a character to the LCD, he wants to be able to pass it a string: LCDPRINT “Hello world”. But that requires his command to be able to parse a string, and this has him diving down the rabbit hole into how MS BASIC parses strings, handles evals, and so on. If you want to know how MS BASIC works on the inside, this is the video for you. This video makes a lot of use of wozmon, which seems an almost ideal tool for this kind of low-level poking around.

All of this is done in [Ben]’s very well rehearsed, accessible, but pulling-no-punches style. Get ready to nerd out. All three of the videos are embedded just below the break.

While it’s not the Altair BASIC that Bill himself was writing about last week, it’s probably a direct descendent, and reading about the Altair version was what spurred [Mark Stevens] to send us the tip. Thanks!

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How Shrinking Feature Size Made Modern Wireless Work

April 5, 2025 by Elliot Williams 4 Comments

If you’re living your life right, you probably know what as MOSFET is. But do you know the MESFET? They are like the faster, uninsulated, Schottky version of a MOSFET, and they used to rule the roost in radio-frequency (RF) silicon. But if you’re like us, and you have never heard of a MESFET, then give this phenomenal video by [Asianometry] a watch. In it, among other things, he explains how the shrinking feature size in CMOS made RF chips cheap, which brought you the modern cellphone as we know it.

MESFET

MOSFET

The basic overview is that in the 1960s, most high-frequency stuff had to be done with discrete parts because the bipolar-junction semiconductors of the time were just too slow. At this time, MOSFETs were just becoming manufacturable, but were even slower still. The MESFET, without its insulating oxide layer between the metal and the silicon, had less capacitance, and switched faster. When silicon feature sizes got small enough that you could do gigahertz work with them, the MESFET was the tech of choice.

As late as the 1980s, you’d find MESFETs in radio devices. At this time, the feature size of the gates and the thickness of the oxide layer in MOSFETs kept them out of the game. But as CPU manufacturers pushed CMOS features smaller, not only did we get chips like the 8086 and 80386, two of Intel’s earliest CMOS designs, but the tech started getting fast enough for RF. And the world never looked back.

If you’re interested in the history of the modern monolithic RF ICs, definitely give the 18-minute video a watch. (You can skip the first three or so if you’re already a radio head.) If you just want to build some radio circuits, this fantastic talk from [Michael Ossmann] at the first-ever Supercon will make you an RF design hero. His secrets? Among them, making the most of exactly these modern everything-in-one-chip RF ICs so that you don’t have to think about that side of things too hard.

Thanks [Stephen] for the tip!

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Lockdown Remote Control Project Is Free And Open

April 4, 2025 by Elliot Williams 8 Comments

If you flew or drove anything remote controlled until the last few years, chances are very good that you’d be using some faceless corporation’s equipment and radio protocols. But recently, open-source options have taken over the market, at least among the enthusiast core who are into squeezing every last bit of performance out of their gear. So why not take it one step further and roll your own complete system?

Apparently, that’s what [Malcolm Messiter] was thinking when, during the COVID lockdowns, he started his own RC project that he’s calling LockDownRadioControl. The result covers the entire stack, from the protocol to the transmitter and receiver hardware, even to the software that runs it all. The 3D-printed remote sports a Teensy 4.1 and off-the-shelf radio modules on the inside, and premium FrSky hardware on the outside. He’s even got an extensive folder of sound effects that the controller can play to alert you. It’s very complete. Heck, the transmitter even has a game of Pong implemented so that you can keep yourself amused when it’s too rainy to go flying.

Of course, as we alluded to in the beginning, there is a healthy commercial infrastructure and community around other open-source RC projects, namely ExpressLRS and OpenTX, and you can buy gear that runs those software straight out of the box, but it never hurts to have alternatives. And nothing is easier to customize and start hacking on than something you built yourself, so maybe [Malcolm]’s full-stack RC solution is right for you? Either way, it’s certainly impressive for a lockdown project, and evidence of time well spent.

Thanks [Malcolm] for sending that one in!

First PCB With The Smallest MCU?

April 4, 2025 by Elliot Williams 30 Comments

[Morten] works very fast. He has already designed, fabbed, populated, and tested a breakout board for the new tiniest microcontroller on the market, and he’s even made a video about it, embedded below.

You might have heard about this new TI ARM Cortex MO micro on these very pages, where we asked you what you’d do with this grain-of-rice-sized chunk of thinking sand. (The number one answer was “sneeze and lose it in the carpet”.)

From the video, it looks like [Morten] would design a breakout board using Kicad 8, populate it, get it blinking, and then use its I2C lines to make a simple digital thermometer demo. In the video, he shows how he worked with the part, from making a custom footprint to spending quite a while nudging it into place before soldering it carefully down.

But he nailed it on the first try, and honestly it doesn’t look nearly as intimidating as we’d feared, mostly because of the two-row layout of the balls. It actually looks easy enough to fan out. Because you can’t inspect the soldering work underneath the chip, he broke out all of the lines to a header to make it quick to check for shorts between those tiny little balls. Smart.

We love to see people trying out the newest hotness. Let us know down in the comments what new parts you’re trying out.

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Vintage Computer Festival East This Weekend

April 4, 2025 by Elliot Williams 6 Comments

If you’re on the US East Coast, you should head on over to Wall, NJ and check out the Vintage Computer Festival East. After all, [Brian Kernighan] is going to be there. Yes, that [Brian Kernighan].

Events are actually well underway, and you’ve already missed the first few TRS-80 Color Computer programming workshops, but rest assured that they’re going on all weekend. If you’re from the other side of the retrocomputing fence, namely the C64 side, you’ve also got a lot to look forward to, because the theme this year is “The Sounds of Retro” which means that your favorite chiptune chips will be getting a workout.

[Tom Nardi] went to VCF East last year, so if you’re on the fence, just have a look at his writeup and you’ll probably hop in your car, or like us, wish you could. If when you do end up going, let us know how it was in the comments!

70 DIY Synths On One Webpage

April 2, 2025 by Elliot Williams 12 Comments

If you want to dip your toes into the deep, deep water of synth DIY but don’t know where to start, [Atarity] has just the resource for you. He’s compiled a list of 70 wonderful DIY synth and noise-making projects and put them all in one place. And as connoisseurs of the bleepy-bloopy ourselves, we can vouch for his choices here.

The collection runs the gamut from [Ray Wilson]’s “Music From Outer Space” analog oddities, through faithful recreations like Adafruit’s XOXBOX, and on to more modern synths powered by simple microcontrollers or even entire embedded Linux devices. Alongside the links to the original projects, there is also an estimate of the difficulty level, and a handy demo video for every example we tried out.

Our only self-serving complaint is that it’s a little bit light on the Logic Noise / CMOS-abuse side of synth hacking, but there are tons of other non-traditional noisemakers, sound manglers, and a good dose of musically useful devices here. Pick one, and get to work!