Retrotechtacular: Right To Repair 1987

In 1987, your portable Osborne computer had a problem. Who you gonna call? Well, maybe the company that made “The Osborne Survival Kit,” a video from Witt Services acquired by the Computer History Museum. The narrator, [Mark Witt], tells us that they’ve been fixing these computers for more than three years, and they want to help you fix it yourself. Those days seem long gone, don’t they?

Of course, one thing you need to know is how to clean your floppy drives. The procedure is easy; even a 10-year-old can do it. At least, we think [William Witt] is about 10 in the video. He did a fine job, and we wonder what he’s up to these days.

The next step was taking the machine apart, but that required adult supervision. In some cases, it also took a soldering iron. As a byproduct, the video inadvertently is a nice tear-down video, too.

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Building A Tiny Organic Swimming Pool With Natural Filtering

When we think of swimming pools, we typically think of large fiberglass, plastic, or concrete constructions full of pristine, clear water. They’re usually maintained in this state with the regular addition of chlorine or other chemical. These kill biological stuff and help filter out dirt and other detritus. However,  [David] likes to do things differently, as he demonstrates with a tiny plunge pool built inside his greenhouse.

The basic construction starts with digging a hole and building up a wall with concrete and bricks. There’s nothing particularly controversial there. It’s roughly 2 meters by 3 meters by 0.8 meters deep. To help the pool maintain heat, there’s a layer of foam insulation in the bottom, while the water is held inside a black liner.

Rather than traditional chemical methods, however, [David] relies on organic methods to maintain the pool. He explains how he uses an aquarium pump to create a “bubble filtered” pool that draws water through a gravel bed to maintain it and keep it clear. It’s a very natural setup, with multiple plants in the water to make it as organic as can be. It’s the kind of thing you’d expect to see at a luxury island resort, but [David’s] got one right in his very own greenhouse.  [David] explains the organic filtering concept in greater detail on his website.

We’ve featured some pool hacks before, too, though more traditional ones than this. Video after the break.

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Hackaday Links: March 24, 2024

Way to rub it in, guys. As it turns out, due to family and work obligations we won’t be able to see the next Great American Eclipse, at least not from anywhere near the path of totality, when it sweeps from Mexico into Canada on April 8. And that’s too bad, because compared to the eclipse back in 2017, “Eclipse 2: Solar Boogaloo” is occurring during a much more active phase in the solar cycle, with the potential for some pretty exciting viewing. The sun regularly belches out gigatons of plasma during coronal mass ejections (CMEs), most of which we can’t see with the naked eye because not only is staring at the sun not a great idea, but most of that activity occurs across the disk of the sun, obscuring the view in the background light. But during the eclipse, we — oops, you — might just get lucky enough to have a solar prominence erupt along the limb of the sun that will be visible during totality. The sun has been quite active lately, as reflected by the relatively high sunspot number, so even though it’s an outside chance, it’s certainly more likely than it was in 2017. Good luck out there.  Continue reading “Hackaday Links: March 24, 2024”

A Dial Phone SIPs Asterisk

An endless source of amusement for those of advancing years can come from handing a rotary phone to a teenager and asking them to dial a number with it. It’s rare for them to be stumped by a piece of technology, after all. [Mnutt]’s 4-year-old son had no such problems when he saw rotary phones at an art exhibition, so what was a parent to do but wire the phone to an Asterisk PBX with shortcut numbers for calls to family and such essential services as a joke line, MTA status, or even a K-pop song.

It’s possible to hook up a pulse dial phone with a SLIC module and a microcontroller, but in this case, a Grandstream SIP box did the trick. These are all-in-one devices that implement a SIP client with a physical connection, and older ones will talk to pulse dialers as well as the more usual tone dialing phones. The phone in question is a vintage American model. Writing this from Europe we were surprised to find a little simpler inside than its transatlantic counterparts of the same era.

An Asterisk install on a Raspberry Pi completed the project, and thus it became a matter of software configuration. It’s a useful run-through for Asterisk dilettantes, even if you haven’t got a 4-year-old. Perhaps you have an old payphone or two!

An ASIC For A Secret File

Some time over a decade ago, the arrival of inexpensive PCB fabrication revolutionised the creation of custom electronics on a budget. It’s now normal for even the smallest projects we feature here to have a professional PCB, which for those of us who started by etching their own with ferric chloride is nothing short of a miracle. When it comes to the ultimate step in custom electronics of doing the same for integrated circuits though, it’s fair to say that this particular art is in its infancy. The TinyTapeout project is a collaborative effort in which multiple designers have the chance to make their own ASIC as a single tile on a chip along others, and [Bitluni] had the chance to participate. His ASIC? A secret file which could be read through his ESP32 to VGA board.

The video below the break then is both the tale of the secret file project, and that of TinyTapeout itself, which is a clever design involving an on-board microcontroller that selects the tile and manages the bus. This revision is Tiny Tapeout 3, which includes 249 tiles of contributor-generated circuitry holding a diverse array of projects.

The secret file itself is a motion GIF, compressed down until the point at which it will just fit on a tile. We’ll preserve the fun by not reveling what it us, but you probably won’t be surprised when you see it in the video.

We’ve featured TinyTapeout more then once, not least when [Matt Venn] gave a talk about it for Supercon 2022.

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Concrete Clears Its Own Snow

Humans are not creatures well suited to cold environments. Without a large amount of effort to provide clothing, homes, and food to areas with substantial winters, very few of us would survive. The same is true of a lot of our infrastructure since things like ice, frost heave, and large temperature swings can all negatively impact buildings, roadways, and other structures. A team at Drexel University in Pennsylvania has created a type of concrete they hope might solve some issues with the material in cold climates.

Specifically when it comes to sidewalks and roadways, traditional methods of snow and ice removal such as plowing and salting are generally damaging to the surface material, with salting additionally being damaging to vehicles. Freeze-thaw cycles aren’t kind to these surfaces either. This concrete, on the other hand, contains a low-temperature liquid paraffin which releases heat when it has a phase change, from a liquid to a solid. By incorporating the material into the concrete, it can warm itself as temperatures drop, maintaining a temperature above freezing to melt ice and snow. The warming effect isn’t indefinite, but lasts a significant amount of time during testing.

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Fail Of The Week: A Potentially Lethal Tattoo Removal Laser Power Supply

Caveat emptor is good advice in general, but in the wilds of eBay, being careful with what you buy could be life-saving. To wit, we present [Les Wright]’s teardown and very ginger power-up of an eBay tattoo-removal laser power supply.

Given that [Les] spent all of around $100 on this widowmaker, we’re pretty sure he knew what he was getting himself into. But he likely wasn’t quite prepared for the scale of the sketchiness this thing would exhibit. The deficiencies are almost too many to number, starting with the enclosure, which is not only made completely of plastic but assembled from individual sheets of flat plastic stock that show signs of being glued together by hand. Even the cooling water tank inside the case is pieced together this way, which probably led to the leaks that corroded the PCBs. Another assembly gem is the pair of screws the big energy storage capacitor is jammed under, presumably to hold it in place — because nothing says quality like a BOM that can’t spring for a couple of cable ties. Click through the break to read more and see the video.

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