Author: Dan Maloney

3288 Articles

Compact Driver Powers Steppers With USB-C PD

August 24, 2024 by 12 Comments

NEMA-17 steppers are (almost) a dime a dozen. They’re everywhere, they’re well-known to hackers and makers, and yet they’re still a bit hard to integrate into projects. That’s because the motor alone isn’t much use, and by the time you find or build a driver and integrate it with a microcontroller, you’ve probably expended more effort than you will on the rest of the project. This USB-C PD stepper driver aims to change that.

What caught our eye about [Josh Rogan]’s PD Stepper is his effort to make this a product rather than just a project. The driver is based on a TMC2209 for silent operation and a lot of torque thanks to the power delivery capabilities of USB-C PD. The PCB is very nicely designed and has an AS5600 rotary magnetic encoder for closed-loop operation. There’s also an ESP32-S3 on-board, so WiFi and Bluetooth operation are possible — perfect for integration into Home Assistant via ESPHome.

[Josh]’s mechanical design is top-notch, too, with a machined aluminum spacer that fits on the back of a NEMA-17 motor perfectly and acts as a heat spreader. A machined polycarbonate cover protects the PCB and makes a very neat presentation. [Josh] has kits available, or you can roll your own with the provided build files.

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A Game Of Snake On A LEGO Mechanical Computer

August 23, 2024 by 6 Comments

Really, [OzzieGerff] had us at “LEGO.” But then he took it to another place entirely and built a completely mechanical, nearly 100% LEGO version of Snake. And it’s just as cool as it sounds.

Mind you, it’s a little hard to grok how this whole contraption works, which has been in the works for a while, but we’ll try to summarize as best we can. The most important aspect of this build is that there are no electronics at all — everything is done with mechanical linkages, with some Technics pneumatic components and a couple of electric motors to provide the oomph. The three main components are the input section, which consists of a two-axis joystick, a tail buffer, which keeps track of the length of the snake’s tail as gameplay progresses, and the largest component, the 16×16 display.

The joystick translates user inputs into pneumatic signals which pass through a mechanical filtering unit that prevents the head of the snake from doubling back on itself. The filtered inputs then pass into the screen reader, a complex device that probes the status of a given pixel on the display and determines the status of the snake’s head. If it touches a snake pixel, the game’s over. Hitting a blank pixel moves the head of the snake by one and takes one pixel off the end, while a food pixel extends the snake’s length.

Keeping track of the length of the snake is the job of the buffer, which uses Technics tank tracks and levers. Setting a one is done by flipping the lever to one side as it passes under the write head; a read head further down the track senses which way the lever is flipped and translates it into a pneumatic signal. The buffer has four channels, one for each possible direction the snake’s head could be moving. The signals drive a screen writer, which moves a pyramidal follower across a series of push-rods that flip the corresponding pixel on the display to show the proper icon. Simplicity itself? No, but the video below will make things a lot clearer.

It doesn’t look like [Ozzie] is quite done with this game, as he doesn’t show any actual gameplay yet. We’d love to see and hear that — we suspect it’ll make quite a racket. We’ll be keeping an eye out for this one, but while we wait, check out this rope braiding machine or watch Lego break steel.

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A Field Guide To The North American Substation

August 22, 2024 by 15 Comments

Drive along nearly any major road in the United States and it won’t be long before you see evidence of the electrical grid. Whether it’s wooden poles strung along the right of way or a line of transmission towers marching across the countryside in the distance, signs of the grid are never far from view but often go ignored, blending into the infrastructure background and becoming one with the noise of our built environment.

But there’s one part of the electrical grid that, despite being more widely distributed and often relegated to locations off the beaten path, is hard to ignore. It’s the electrical substation, more than 55,000 of which dot the landscape of the US alone. They’re part of a continent-spanning machine that operates as one to move electricity from where it’s produced to where it’s consumed, all within the same instant of time. These monuments of galvanized steel are filled with strange, humming equipment of inscrutable purpose, seemingly operating without direct human intervention. But if you look carefully, there’s a lot of fascinating engineering going on behind those chain-link fences with the forbidding signage, and the arrangement of equipment within them tells an interesting story about how the electrical grid works, and what the consequences are when it doesn’t.

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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”” →