Author: Dan Maloney

3215 Articles

Happy Birthday To Dad, Retrocomputer Style

August 22, 2024 by 3 Comments

For those of us who lived through the early 8-bit computing revolution — the tail end, in our case — it’s hard to believe that there’s a second wave of retrocomputing nostalgia underway. But as this bit-banged TRS-80 birthday bonus pack shows, the first generation did a pretty good job passing the retro torch.

With his father’s 70th birthday coming up and full of “borrowed nostalgia” for the good old days, [Josh Sucher] scored a TRS-80 off eBay and experimented with what could be possible. After 50-odd years, the machine needed a bit of TLC, including a new power supply, some keyboard repairs, and the usual recapping. He also had to soup the machine up a bit, given that its original capabilities were so limited.

Chief among these mods was a rudimentary IP stack thanks to a TRS-IO card, which emulates a lot of functionality of the original TRS-80 Expansion Module and adds an ESP-32 for WiFi capability. This allowed [Josh] to get a neat “Dadbot” chatbot going on the machine, using years of his dad’s text messages to train the model. There’s also a game of Go, an RPG based on his parents’ lives, and a local news and weather app. Most impressive, though, is the bit-banged audio app that uses the TRS-80’s cassette interface to play a passable rendition of “Happy Birthday to You.” The video below has the full demo.

It’s clear that this lengthy project was a labor of love, and we approve of the results. It’s been a long, long time since we first caught wind of the TRS-80 through the Radio Shack catalog, and projects like this make us feel like scratching up one for ourselves to play with.

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Hackaday Links: August 18, 2024

August 18, 2024 by 4 Comments

They’re back! The San Francisco autonomous vehicle hijinks, that is, as Waymo’s fleet of driverless cars recently took up the fun new hobby of honking their horns in the wee hours of the morning. Meat-based neighbors of a Waymo parking lot in the South Market neighborhood took offense at the fleet of autonomous vehicles sounding off at 4:00 AM as they shuffled themselves around in the parking lot in a slow-motion ballet of undetermined purpose. The horn-honking is apparently by design, as the cars are programmed to tootle their horn trumpets melodiously if they detect another vehicle backing up into them. That’s understandable; we’ve tootled ourselves under these conditions, with vigor, even. But when the parking lot is full of cars that (presumably) can’t hear the honking and (also presumably) know where the other driverless vehicles are as well as their intent, what’s the point? Luckily, Waymo is on the case, as they issued a fix to keep the peace. Unfortunately, it sounds like the fix is just to geofence the lot and inhibit honking there, which seems like just a band-aid to us.

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Retrotechtacular: Powerline Sagging And Stringing In The 1950s

August 17, 2024 by 13 Comments

While high-voltage transmission lines are probably the most visible components of the electrical grid, they’re certainly among the least appreciated. They go largely unnoticed by the general public — quick, name the power line closest to you right now — at least until a new one is proposed, causing the NIMBYs and BANANAs to come out in force. To add insult to injury, those who do notice the megastructures that make modern life possible rarely take a moment to appreciate the engineering that goes into stringing up hundreds of miles of cable and making sure it stays up.

Not so the Bonneville Power Administration, the New Deal-era federal agency formed to exploit the hydroelectric abundance of the Pacific Northwest of the United States, which produced this 1950 gem detailing the stringing and sagging of power lines. Unsurprisingly, the many projects needed to wire together the often remote dams to the widely distributed population centers in an area that was only just starting to see growth began in the BPA’s offices, where teams of engineers hunched over desks worked out the best routes. Paper, pencil, and slide rules were the tools of the trade, along with an interesting gadget called a conductor sag template, a hardware implementation of the catenary equation that allowed the “sagger” to determine the height of each tower. The conductors, either steel-cored aluminum or pure copper, were also meticulously selected based on tensile strength, expected wind and ice loading, and the electrical load the line was expected to carry.

Once the engineers had their say, the hard work of physically stringing the wires began out in the field. One suspects that the work today is much the same as it was almost eighty years ago, save for much more stringent health and safety regulations. The prowess needed to transfer the wires from lifting sheaves to the insulators is something to behold, and the courage required to work from ladders hanging from wires at certain death heights is something to behold. But to our mind, the real heroes were the logistics fellows, who determined how much wire was needed for each span and exactly where to stage the reels. It’s worth sparing a moment’s thought for the daring photographer who captured all this action, likely with little more than a leather belt and hemp rope for safety.

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Fighting The Scourge Of “Screwdriver Mange”

August 16, 2024 by 45 Comments

We’ve all got our favorite hand tools, and while the selection criteria are usually pretty subjective, it usually boils down to a combination of looks and feel. In our opinion, the king of both these categories when it comes to screwdrivers is those clear, hard acetate plastic handles, which are a joy to use — at least until the plastic starts to degrade and exude a characteristically funky aroma.

But perhaps we can change that if these experiments on screwdriver “mange” hold up. That’s [357magdad]’s unappealing but accurate description of the chemical changes that eventually occur in the strong, hard, crystal-clear handles of your favorite screwdrivers. The polymer used for these handles is cellulose acetate butyrate, or CAB, which is mostly the same cellulose acetate that replaced the more explode-y cellulose nitrate in things like pool balls and movie film, except with some of the acetate groups replaced with a little butyric acid. The polymer is fine at first, but add a little UV light and over time the outer layer of CAB decomposes into a white flaky cellulose residue while the butyric acid volatilizes, creating the characteristic odor of vomitus. Lovely.

In the video below, [357magdad] takes a look at different concoctions that all allegedly cure the mange. TL, DW; it was a dunk in household ammonia that performed the best, well ahead of other common agents like vinegar and bleach. The ammonia — or more precisely, ammonium hydroxide — works very quickly on the cellulose residue, dissolving it readily and leaving the handle mange-free and looking nearly new after some light scrubbing. None of the other agents came close, although acetone did manage to clear up the mange a bit, at the cost of softening the underlying CAB in a process that’s probably similar to acetone smoothing ABS prints.

As for the funky smell, well, the results were less encouraging. Nothing really got rid of the pukey smell, even a roll in baking soda. We suspect there won’t be much for that, since humans can detect it down to 10 parts per million. Consider it the price to pay for a nice-looking screwdriver that feels so good in your hand. Continue reading “Fighting The Scourge Of “Screwdriver Mange”” →

Hackaday Podcast Episode 284: Laser Fault Injection, Console Hacks, And Too Much Audio

August 16, 2024 by 1 Comment

The summer doldrums are here, but that doesn’t mean that Elliot and Dan couldn’t sift through the week’s hack and find the real gems. It was an audio-rich week, with a nifty microsynth, music bounced off the moon, and everything you always wanted to know about Raspberry Pi audio but were afraid to ask. We looked into the mysteries of waveguides and found a math-free way to understand how they work, and looked at the way Mecanum wheels work in the most soothing way possible. We also each locked in on more classic hacks, Elliot with a look at a buffer overflow in Tony Hawks Pro Skater and Dan with fault injection user a low-(ish) cost laser setup. From Proxxon upgrades to an RC submarine to Arya’s portable router build, we’ve got plenty of material for your late summer listening pleasure.

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Unusual Tool Gets An Unusual Repair

August 15, 2024 by 25 Comments

In today’s value-engineered world, getting a decade of service out of a cordless tool is pretty impressive. By that point you’ve probably gotten your original investment back, and if the tool gives up the ghost, well, that’s what the e-waste bin is for. Not everyone likes to give up so easily, though, which results in clever repairs like the one that brought this cordless driver back to life.

The Black & Decker “Gyrodriver,” an interesting tool that is controlled with a twist of the wrist rather than the push of a button, worked well for [Petteri Aimonen] right up until the main planetary gear train started slipping thanks to stripped teeth on the plastic ring gear. Careful measurements of one of the planetary gears to determine parameters like the pitch and pressure angle of the teeth, along with the tooth count on both the planet gear and the stripped ring.

Here, most of us would have just 3D printed a replacement ring gear, but [Petteri] went a different way. He mentally rolled the ring gear out, envisioning it as a rack gear. To fabricate it, he simply ran a 60° V-bit across a sheet of steel plate, creating 56 parallel grooves with the correct pitch. Wrapping the grooved sheet around a round form created the ring gear while simultaneously closing the angle between teeth enough to match the measured 55° tooth angle in the original. [Petteri] says he soldered the two ends together to form the ring; it looks more like a weld in the photos, but whatever it was, the driver worked well after the old plastic teeth were milled out and the new ring gear was glued in place.

We think this is a really clever way to make gears, which seems like it would work well for both internal and external teeth. There are other ways to do it, of course, but this is one tip we’ll file away for a rainy day.

Ryobi Battery Pack Gives Up Its Secrets Before Giving Up The Ghost

August 14, 2024 by 44 Comments

Remember when dead batteries were something you’d just toss in the trash? Those days are long gone, thankfully, and rechargeable battery packs have put powerful cordless tools in the palms of our hands. But when those battery packs go bad, replacing them becomes an expensive proposition. And that’s a great excuse to pop a pack open and see what’s happening inside.

The battery pack in question found its way to [Don]’s bench by blinking some error codes and refusing to charge. Popping it open, he found a surprisingly packed PCB on top of the lithium cells, presumably the battery management system judging by the part numbers on some of the chips. There are a lot of test points along with some tempting headers, including one that gave up some serial data when the battery’s test button was pressed. The data isn’t encrypted, but it is somewhat cryptic, and didn’t give [Don] much help. Moving on to the test points, [Don] was able to measure the voltage of each battery in the series string. He also identified test pads that disable individual cells, at least judging by the serial output, which could be diagnostically interesting.  [Don]’s reverse engineering work is now focused on the charge controller chip, which he’s looking at through its I2C port. He seems to have done quite a bit of work capturing output and trying to square it with the chip’s datasheet, but he’s having trouble decoding it.

This would be a great place for the Hackaday community to pitch in so he can perhaps get this battery unbricked. We have to admit feeling a wee bit responsible for this, since [Don] reports that it was our article on reverse engineering a cheap security camera that inspired him to dig into this, so we’d love to get him some help.