Persistence Pays In TI-99/4A Cassette Tape Data Recovery

In the three or four decades since storing programs on audio cassettes has been relevant, a lot of irreplaceable personal computing history has been lost to the ravages of time and the sub-optimal conditions in the attics and basements where tapes have been stored. Luckily, over that time we’ve developed a lot of tools and techniques that might make it possible to recover some of these ancient treasures. But as [Noel] shows us, recovering data from cassette tapes is a tricky business.

His case study for the video below is a tape from a TI-99/4A that won’t load. A quick look in Audacity at the audio waveform seems to show the problem — an area of severely attenuated signal. Unfortunately, no amount of boosting and filtering did the trick, so [Noel] had to dig a bit deeper. It turns out that the TI tape interface standard, with its redundant data structure, was somewhat to blame for the inability to read this particular tape. As [Noel] explains, each 64-bit data record is recorded to tape twice, along with a header and a checksum. If neither record decodes correctly, then tape playback just stops.

Luckily, someone who had already run into this problem spun up a Windows program to help. CS1er — our guess would be “Ceaser” — takes WAV file input and loads each record, simply flagging the bad ones instead of just bailing out. [Noel] used the program to analyze multiple recordings of the same data and eventually got enough good records to reassemble the original program, a game called Dogfight — or was it Gogfight? Either way, he managed to get most of the data off the tape, and since it was a BASIC program, it was pretty easy to figure out the missing bytes by inspection.

[Noel]’s experience will no doubt be music to the ears of the TI aficionados out there. Of which we’ve seen plenty, from the TI-99 demoscene to running Java on one, and whatever this magnificent thing is.

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Gym Equipment Converted To Generator

Energy cannot be created or destroyed, but the most likely eventual conclusion of changing it from one form or another will be relatively useless heat. For those that workout with certain gym equipment, the change from chemical energy to heat is direct and completely wasted for anything other than keeping in shape. [Oliver] wanted to add a step in the middle to recover some of this energy, though, and built some gym equipment with a built-in generator.

Right now he has started with the obvious exercise bike stand, which lends itself to being converted to a generator quite easily. It already had a fairly rudimentary motor-like apparatus in it in order to provide mechanical resistance, so at first glance it seems like simply adding some wires in the right spots would net some energy output. This didn’t turn out to be quite so easy, but after a couple of attempts [Oliver] was able to get a trickle of energy out to charge a phone, and with some more in-depth tinkering on the motor he finally was able to get a more usable amount of energy to even charge a laptop.

He estimates around 30 watts of power can be produced with this setup, which is not bad for a motor that was never designed for anything other than mechanical resistance. We look forward to seeing some other equipment converted to produce energy too, like a rowing machine or treadmill. Or, maybe take a different route and tie the exercise equipment into the Internet connection instead.

Building A Serial Bus To Save An Old Hard Drive

Universal Serial Bus has been the de facto standard for sending information to and from computer peripherals for almost two decades, but despite the word “universal” in the name this wasn’t always the case. Plenty of competing standards, including USB, existed in the computing world in the decades before it came to dominance, and if you’re trying to recover data from a computer without USB you might have to get creative with how it’s done.

[Ben] recently came across a 80486 with this problem, so he had to get creative to recover the contents of the drive. He calls it the “lunchbox” computer due to its form factor, and while it doesn’t have USB it does have a tried-and-trusted serial port to communicate with other computers. [Ben] wrote up a piece of software for both the receiving computer and the sending computer in order to copy the drive sectors one by one across a serial link to a standalone computer running Windows XP, and was able to recover the contents of the drive that way instead.

All of the code [Ben] wrote is available on his GitHub page for anyone looking to boot up a 30-year-old computer again. While it might sound uncommon, computers of this vintage are still around running things like CNC machines or old mainframes.

The Dangerously Delightful Homemade Rockets Of Thailand

Every once in a while, we here at Hackaday stumble across something that doesn’t quite fit in with all the other amazing hacks we feature, but still seems like something that our dear readers need to see as soon as possible. This video of homemade rockets in Thailand is one of those things.

It comes to us from our friend [Leo Fernekes], who documents a form of amateur rocketry that makes the Estes rockets of our youth look pretty tame. It’s far easier to watch than it is to describe, but for a quick summary, the rockets are bamboo rings with a steel pipe across the diameter. The pipe is packed with homemade gunpowder and provided with nozzles that create both thrust and rotation. When ignited by torches touched to seriously sketchy primers, the rocket starts to spin up, eventually rising off the launch pad and screwing itself into the sky on a twisting column of gray smoke.

At three or four meters across, these are not small vehicles. Rather than letting a steel pipe plummet back to Earth from what looks like several hundred meters altitude, the rocketeers have devised a clever recovery system that deploys a parachute when the rocket motor finally melts through some plastic straps. The use of banana tree bark as a heat shield to protect the parachute is simple but effective; which is really the way you can describe the whole enterprise. [Leo] has another way to describe it: “Dangerously negligent madness,” with all due respect and affection, of course. It looks like a big deal, too — the air is obviously filled with the spirit of competition, not to mention the rotten-egg stench of gunpowder.

Should you try this at home? Probably not — we can think of dozens of reasons why this is a bad idea. Still, it’s amazing to watch, and seeing how much altitude these cobbled-up rockets manage to gain is truly amazing. Hats off to [Leo] for finding this for us.

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SpaceX Drops The Ball On Catching Fairings

You don’t have to look very hard to find another rousing success by SpaceX. It’s a company defined by big and bold moves, and when something goes right, they make sure you know about it. From launching a Tesla into deep space to the captivating test flights of their next-generation Starship spacecraft, the private company has turned high-stakes aerospace research and development into a public event. A cult of personality has developed around SpaceX’s outlandish CEO Elon Musk, and so long as he’s at the helm, we can expect bigger and brighter spectacles as he directs the company towards its ultimate goal of putting humans on Mars.

Of course, things don’t always go right for SpaceX. While setbacks are inevitable in aerospace, the company has had a few particularly embarrassing failures that could be directly attributed to their rapid development pace or even operational inexperience. A perfect example is the loss of the Israeli AMOS-6 satellite during a static fire of the Falcon 9’s engines on the launch pad in 2016, as industry experts questioned why the spacecraft had even been mounted to the rocket before it had passed its pre-flight checks. Since that costly mistake, the company has waited until all engine tests have been completed before attaching the customer’s payload.

SpaceX’s concept art for propulsive landing

But sometimes the failure isn’t so much a technical problem as an inability for the company to achieve their own lofty goals. Occasionally one of Musk’s grand ideas ends up being too complex, dangerous, or expensive to put into practice. For instance, despite spending several years and untold amounts of money perfecting the technology involved, propulsive landings for the Crew Dragon were nixed before the idea could ever fully be tested. NASA was reportedly uncomfortable with what they saw as an unnecessary risk compared to the more traditional ocean splashdown under parachutes; it would have been an impressive sight to be sure, but it didn’t offer a substantive benefit over the simpler approach.

A similar fate recently befell SpaceX’s twin fairing recovery ships Ms. Tree and Ms. Chief, which were quietly retired in April.¬†These vessels were designed to catch the Falcon’s school bus sized payload fairings as they drifted down back to Earth using massive nets suspended over their decks, but in the end, the process turned out to be more difficult than expected. More importantly, it apparently wasn’t even necessary in the first place.

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A New Era Of Spacecraft Delivers Science On Time

When the Space Shuttle Atlantis rolled to a stop on its final mission in 2011, it was truly the end of an era. Few could deny that the program had become too complex and expensive to keep running, but even still, humanity’s ability to do useful work in low Earth orbit took a serious hit with the retirement of the Shuttle fleet. Worse, there was no indication of when or if another spacecraft would be developed that could truly rival the capabilities of the winged orbiters first conceived in the late 1960s.

While its primary function was to carry large payloads such as satellites into orbit, the Shuttle’s ability to retrieve objects from space and bring them back was arguably just as important. Throughout its storied career, sensitive experiments conducted at the International Space Station or aboard the Orbiter itself were returned gently to Earth thanks to the craft’s unique design. Unlike traditional spacecraft that ended their flight with a rough splashdown in the open ocean, the Shuttle eased itself down to the tarmac like an airplane. Once landed, experiments could be quickly unloaded and transferred to the nearby Space Station Processing Facility where science teams would be waiting to perform further processing or analysis.

Atlantis is towed from the runway for payload processing.

For 30 years, the Space Shuttle and its assorted facilities at Kennedy Space Center provided a reliable way to deliver fragile or time-sensitive scientific experiments into the hands of researchers just a few hours after leaving orbit. It was a valuable service that simply didn’t exist before the Shuttle, and one that scientists have been deprived of ever since its retirement.

Until now. With the successful splashdown of the first Cargo Dragon 2 off the coast of Florida, NASA is one step closer to regaining a critical capability it hasn’t had for a decade. While it’s still not quite as convenient as simply rolling the Shuttle into the Orbiter Processing Facility after a mission, the fact that SpaceX can guide their capsule down into the waters near the Space Coast greatly reduces the time required to return experiments to the researchers who designed them.

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Recovering Metal From Waste

Refining precious metals is not as simple as polishing rocks that have been dug out of the ground. Often, complex chemical processes are needed to process the materials properly or in high quantities, but these processes leave behind considerable waste. Often, there are valuable metals left over in these wastes, and [NerdRage] has gathered his chemistry equipment to demonstrate how it’s possible to recover these metals.

The process involved looks to recover copper and nitric acid from copper nitrate, a common waste byproduct of processing metal. While a process called thermal decomposition exists to accomplish this, it’s not particularly efficient, so this alternative looks to improve the yields you could otherwise expect. The first step is to react the copper nitrate with sulfuric acid, which results in nitric acid and copper sulfate. From there, the copper sulfate is placed in an electrolysis cell using a platinum cathode and copper anodes to pass current through it. After the process is complete, all of the copper will have deposited itself on the copper electrodes.

The other interesting thing about this process, besides the amount of copper that is recoverable, is that the sulfuric acid and the nitric acid are recoverable, and able to be used again in other processes. The process is much more efficient than thermal decomposition and also doesn’t involve any toxic gasses either. Of course, if collecting valuable metals from waste is up your alley, you can also take a look at recovering some gold as well.

Thanks to [Keith] for the tip!

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