COSMAC Elf Calculator Gets New Firmware

Everyone remembers their first. Their first CPU, that is. For many of us, it was the RCA 1802 thanks to the COSMAC Elf articles that ran in Popular Electronics. The later versions of the chip family were much better but were never as popular, but the 1805 did find its way into a printing calculator for dimensions from a company named Boyd. Some of these recently showed up on the surplus market and–of course–were subsequently hacked.

[Bill Rowe] is active in the groups that still work with the 1802. Because of some specialized uses you can still get the chips readily, some four decades after they were new. Other computers at the time were difficult to build and relatively expensive, while for $100 almost anyone could wire wrap a simple 1802-based computer together in a weekend or less.

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Bicycle Racing In Space Could be a Thing

It’s 2100 AD, and hackers and normals live together in mile-long habitats in the Earth-Moon system. The habitat is spun up so that the gravity inside is that of Earth, and for exercise, the normals cycle around on bike paths. But the hackers do their cycling outside, in the vacuum of space.

How so? With ion thrusters, rocketing out xenon gas as the propellant. And the source of power? Ultimately that’s the hackers’ legs, pedaling away at a drive system that turns two large Wimshurst machines.

Those Wimshurst machines then produce the high voltage needed for the thruster’s ionization as well as the charge flow. They’re also what gives the space bike it’s distinctly bicycle-like appearance. And based on the calculations below, this may someday work!

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Horns Across America: The AT&T Long Lines Network

A bewildering amount of engineering was thrown at the various challenges presented to the United States by the end of World War II and the beginning of the Cold War. From the Interstate Highway System to the population shift from cities to suburbs, infrastructure of all types was being constructed at a rapid pace, fueled by reasonable assessments of extant and future threats seasoned with a dash of paranoia, and funded by bulging federal coffers due to post-war prosperity and booming populations. No project seemed too big, and each pushed the bleeding edge of technology at the time.

Some of these critical infrastructure projects have gone the way of the dodo, supplanted by newer technologies that rendered them obsolete. Relics of these projects still dot the American landscape today, and are easy to find if you know where to look. One that always fascinated me was the network of microwave radio relay stations that once stitched the country together. From mountaintop to mountaintop, they stood silent and largely unattended, but they once buzzed with the business of a nation. Here’s how they came to be, and how they eventually made themselves relics.

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Firework Shows, The Vintage Atari Way

In the summer of 1987, the Atari magazine ST-Log caried a piece entitled “Atari Sets Off Fireworks!”, a profile of the use of Atari computers in professional firework displays by Astro Pyrotechnics, a now-defunct California company. Antic podcast host [Kevin Savetz] tracked down the fireworks expert interviewed in 1987, [Robert Veline], and secured not only an interview, but a priceless trove of photographs and software. These he has put online, allowing us a fascinating glimpse into the formative years of computerized pyrotechnics.

The system uses not one, but two Ataris. An ST has all the display data and scheduling set up in the Zoomracks card file software, this is then exported to an 800XL which does the work of running the display. We’re told the code for the 800XL is loaded on a ROM cartridge for reliability. The 800XL is mounted in an aluminium briefcase with a small CRT monitor and battery, and a custom interface board stuffed with TO220 power transistors to fire the pyrotechnics themselves.

It’s unlikely that you’ll be breaking out a vintage Atari yourselves to fun a firework show three decades later, but the opportunity to examine in detail a real-world contemporary commercial use of a now-vintage computer doesn’t come along too often. You can read the original article on the Internet Archive, and listen to the [Veline] interview on the podcast episode.

This is the first Atari firework controller we’ve brought you, but we’ve shown you plenty of others like this beautifuly-executed Arduino build. And if you wonder how to trigger the fireworks themselves, how about destroying a resistor?

Old Chart Recorder becomes Single-Pixel Scanner

With so many ways to capture images from paper, do we really need another one? Especially one that takes 15 minutes to capture a 128×128 pixel image? Probably not, but building a single-pixel RGB scanner is pretty instructive, and good clean fun to boot.

We have to admit that when [Kerry Wong] scored an ancient Hewlett-Packard X-Y chart recorder a while back, we wondered if it would lead to anything useful. One may quibble with the claim that the Lorenz attractor plotter he built with it is useful, and this single pixel scanner is equally suspect, but we like the idea. Using an Arduino to drive the X- and X-axis of the recorder through a raster pattern over the bed and replacing the pen with an RGB sensor board, [Kerry] was able to collect the color data for each pixel and reconstruct the image. It wouldn’t be too hard to replicate this if you don’t have an analog X-Y recorder, which just goes to show that not everything needs to be steppers and digital to get something useful done. Or at least semi-useful.

As for the RGB sensor used, they’ve made appearances here many times before, mostly in M&M sorters but with the occasional synesthesia simulator.

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Two-Bit Astrophotography

The Game Boy Camera is a 128×112 pixel sensor from 1998 that was probably the first digital camera in many, many homes. There’s not much you can do with it now, besides replicate old Neil Young album covers and attempting and failing to impress anyone born after the year 1995. Nevertheless, screwing around with old digital cameras is cool, so [Alex] strapped one fo these Game Boy Cameras to an old telescope.

For any astrophotography endeavor, the choice of telescope is important. For this little experiment, [Alex] used a 6” Fraunhofer telescope built in 1838 at the Old Observatory of Leiden. The Game Boy with Camera was attached to the scope using a universal cell phone adapter. Apparently the ‘universal’ in this universal cell phone adapter is accurate – the setup was easy and [Alex] quickly got an image of a clocktower on his Game Boy.

Turning to the heavens, [Alex] took a look at the most interesting objects you can see with a 6-inch telescope. Images of the moon turned out rather well, with beautiful 2-bit dithering along the terminator. Jupiter was a bright white spot in a sea of noise, but [Alex] could see four slightly brighter pixels orbiting where Stellarium predicted the Galilean moons would be.

Was this experiment a success? Between cloudy nights and a relatively small telescope, we’re saying yes. These are pretty impressive results for such a terrible digital camera.

Fixing Bugs In Ancient BASIC Games

Before everyone learned programming on Stack Exchange, things were much different. Computer magazines had BASIC programs in them, which readers would type out, line by line, and hit RUN. In theory, this is a terrible way to learn programming; it’s simply rote recitation without any insight into what the code is actually doing. Of course, copying and pasting from Stack Exchange is exactly the same thing, so maybe these magazines were ahead of the curve.

[0xA000] recently came across one of his old computer magazines containing the type-in listing for Blindganger, a game where you wander a maze blindly. When [0xA000] typed this game into his C64 back in 1988, the game didn’t work. Thirty years later, he decided to give it another go and ended up fixing bugs in an old computer game.

When [0xA000] typed this game into his computer back in 1988, the map just didn’t work, and the final screen revealed a maze where the walls were where they shouldn’t be. A quick Google turned up a disk image of the same game that had the same problem. This bug was obviously in the section of code that draws the map at the end of the game, so [0xA000] started looking there. The offending typo in the code was an $F4 instead of an $F5, or 244 instead of 255. This shifted the colors of the map by 11 positions, meaning the locations marked as visited in the final screen were wrong. Whether this bug cropped up in development or was just a simple typo when typesetting the magazine doesn’t really matter now; after 29 years, this bug is fixed.