Printed Propeller Blades Repair Indoor Flyer

December 9, 2022 by Tom Nardi 5 Comments

Fair warning for readers with a weak stomach, the video below graphically depicts an innocent rubber band airplane being obliterated in mid-air by a smug high-tech RC helicopter. It’s a shocking display of airborne class warfare, but the story does have a happy ending, as [Concrete Dog] was able to repair his old school flyer with some very modern technology: a set of 3D printed propeller blades.

Now under normal circumstances, 3D printed propellers are a dicey prospect. To avoid being torn apart by the incredible rotational forces they will be subjected to, they generally need to be bulked up to the point that they become too heavy, and performance suffers. The stepped outer surface of the printed blade doesn’t help, either.

But in a lightweight aircraft powered by a rubber band, obviously things are a bit more relaxed. The thin blades [Concrete Dog] produced on his Prusa Mini appear to be just a layer or two thick, and were printed flat on the bed. He then attached them to the side of a jar using Kapton tape, and put them in the oven to anneal for about 10 minutes. This not only strengthened the printed blades, but put a permanent curve into them.

The results demonstrated at the end of the video are quite impressive. [Concrete Dog] says the new blades actually outperform the originals aluminum blades, so he’s has to trim the plane out again for the increased thrust. Hopefully the extra performance will help his spindly bird avoid future aerial altercations.

On the electrically powered side of things, folks have been trying to 3D print airplane and quadcopter propellers for almost as long as desktop 3D printers have been on the market. With modern materials and high-resolution printers the idea is more practical than ever, though it’s noted they don’t suffer crashes very well.

Continue reading “Printed Propeller Blades Repair Indoor Flyer” →

A repair stand for bicycles with an integrated scale

DIY Repair Stand Holds Your Bike And Weighs It

December 4, 2022 by Robin Kearey 24 Comments

If you’ve ever done maintenance or repair work on your bicycle, you’ll know that positioning a bike in your workshop isn’t trivial. You can use your bike’s kickstand, or lean it against a wall, but then you can’t work on the wheels. You can place it upside-down, but then the shifters and brake levers are hard to reach. You can hang it from the ceiling, but then you first need to install hooks and cables in hard-to-reach places. Ideally you’d want to have one of those standing clamp systems that the pros use, but their price is typically beyond a hobbyist’s budget.

Or at least, that’s how it used to be. As [Dane Kouttron] discovered, a simple wall-mounted bike clamp can be had for as little as $35 on eBay, and can easily be converted into a smart mobile repair stand. [Dane] fashioned an adjustable stand from some steel pipes he had lying around, and 3D-printed an adapter bracket to mount the bike clamp on it. This worked fine, but why stop at a simple clamp when you can expand it with, say, an integrated scale to weigh your bikes while you work on them? Continue reading “DIY Repair Stand Holds Your Bike And Weighs It” →

How To Repair? The Death Of Schematics

November 21, 2022 by Al Williams 97 Comments

There was a time when, if you were handy with a soldering iron, you could pretty easily open up a radio or TV repair business. You might not get rich, but you could make a good living. And if you had enough business savvy to do sales too, you could do well. These days there aren’t many repair shops and it isn’t any wonder. The price of labor is up and the price of things like TVs drops every day. What’s worse is today’s TV is not only cheaper than last year’s model, but probably also better. Besides that, TVs are full of custom parts you can’t get and jam-packed into smaller and smaller cases.

Case in point, I saw a “black Friday” ad for a 40-inch 1080p flatscreen with a streaming controller for $98. Granted, that’s not huge by today’s standards and I’m sure it isn’t a perfect picture. But for $98? Even a giant high-quality TV these days might cost a bit more than $1,000 and you can get something pretty great for well under $500.

Looking back, a Sears ad showed a great deal on a 19″ color TV in 1980. The price? $399. That doesn’t sound too bad until you realize that today that would be about $1,400. So with a ratio of about 3.5 to 1, a $30/hour service call would be, today, $105. So for an hour’s service call with no parts, I could just buy that 40″ TV. Add even one simple part or another hour and I’m getting close to the big league TVs.

Did you ever wonder how TV repair technicians knew what to do? Well, for one thing, most of the time you didn’t have to. A surprising number of calls would be something simple like a frayed line cord or a dirty tuner. Antenna wires destroyed by critters was common enough. In the tube days, you could pretty easily swap tubes to fix the bulk of actual problems.

Continue reading “How To Repair? The Death Of Schematics” →

TV Repair By Mail

November 17, 2022 by Al Williams 49 Comments

I don’t think there was ever a correspondence school called the “Close Cover Before Striking School” but since book matches — which used to be a thing when most people smoked — always had that text on them anyway perhaps there should have been. There was a time when electronic magazines, billboards, and even book matches were constantly bombarding us with ads to have a career in electronics. Or computers. Or TV repair. So while we think of distance learning as a new idea, really it is just the evolution of these old correspondence schools which date back quite some time.

How far exactly? Hard to say. There’s evidence of some distance learning going back as far as 1728. In 1837, there was a correspondence course to learn shorthand. By 1858, the University of London started its external program for correspondence work and the University of Chicago had a home study division in 1892. Radio was an early choice of topic, too. In the United States, the United Wireless Telegraph company started a training school — later the Marconi Institute — in 1909. However, it is doubtful that there was any correspondence training going on there until much later.

Continue reading “TV Repair By Mail” →

An LCD mounted inside a Roland synthesizer

Reverse-Engineering A Display Protocol To Repair A Roland Synthesizer

October 15, 2022 by Robin Kearey 26 Comments

Repairing electronic devices isn’t as hard as it used to be. Thanks to the internet, it’s easy to find datasheets and application notes for any standard component inside your gadget, and once you’ve found the faulty one, you simply buy a replacement from one of a million web shops — assuming you don’t end up with a fake, of course. When it comes to non-standard components, however, things get more difficult, as [dpeddi] found out when a friend asked him for help in repairing a Roland Juno-G synthesizer with a broken display.

The main issue here was the fact that the display in question was a custom design, with no replacement or documentation available. The only thing [dpeddi] could figure out from the service manual was the basic pinout, which showed a parallel interface with two lines labelled “chip select” — an indication that the display contained two separate controllers. But the exact protocol and data format was not documented, so [dpeddi] brought out his logic analyzer to try and decode the signals generated by the synthesizer.

After a bit of trial and error, he was able to figure out the protocol: it looked like the display contained two KS0713-type LCD controllers, each controlling one half of the screen. Finding a compatible replacement was still proving difficult, so [dpeddi] decided instead to decode the original signals using a microcontroller and show the picture on a modern LCD driven by SPI. After some intial experiments with an ESP32, it turned out that the task of reading two reasonably fast parallel buses and driving an even faster serial one was a bit too much for the ESP, so [dpeddi] upgraded to a Raspberry Pi Pico. This worked a treat, and thanks to a 3D-printed mounting bracket, the new display also fit snugly inside the Roland’s case.

The Pico’s code is available on [dpeddi]’s GitHub page, so if you’ve also got a dodgy display in your Juno-G you can simply download it and use it to plug in a brand-new display. However, the method of reverse-engineering an existing display protocol and translating it to that of a new one is pretty universal and should come in handy when working with any type of electronic device: say, a vintage calculator or multimeter, or even another synthesizer.

A bike computer sits on a wooden background. The back of the bike computer has a 3D printed attachment with two white translucent zip ties running through the back.

Repairing A Bike GPS With 3D Printing

October 7, 2022 by Navarre Bartz 10 Comments

We love hacks that keep gadgets out of the trash heap, and [Brieuc du Maugouër] has us covered with this 3D printable replacement mount he designed for his bike GPS.

One of the most frustrating ways a gadget can fail is when a small, but critical part of the device fails. [du Maugouër] combined a 3D printed back and four M2x6mm screws to make a robust new mount to replace the broken OEM mount on his handlebar-mounted GPS. Slots for zip tie mounting are included in case the replacement mount breaks before yet another replacement can be printed. Apparently [du Maugouër] agrees with Chief O’Brien that “in a crunch, I wouldn’t like to be caught without a second backup.” [Youtube]

It’s exciting that we’re finally in a time when 3D printed replacement parts are living up to their potential. This would be a lot easier if more manufacturers posted 3D printed design files instead of getting them pulled from 3D file platforms, but makers will find a way regardless of OEM approval.

We’ve covered a lot of bike hacks over the years including DIY Bike Computers and GPS Trackers. Do you have a project that keeps something from becoming trash or might save the world another way? There’s still time to enter the Save the World Wildcard round of the Hackaday Prize (closes October 16th).

Hackaday Prize 2022: Repairing A Vintage Laptop With Modern Components

July 27, 2022 by Robin Kearey 23 Comments

Laptop computers may be ubiquitous today, but there was a time when they were the exclusive preserve of rich businesspeople. Back in the early ’90s, the significant added cost of portability was something that few were willing to pay. As a result, not many laptops from those days survive; for those that do, keeping them running can be quite a challenge due to their compact construction and use of non-standard components.

[Adalbert] ran into these problems when he got his hands on a Toshiba T3200SXC from 1991. As the first laptop ever to feature a color TFT display, it’s very much worth preserving as an historical artifact. Sadly, the original display was no longer working: it only displayed a very faint image and went completely blank soon after. Leaky capacitors then destroyed the power supply board, leaving the laptop completely dead. [Adalbert] then began to ponder his options, which ranged from trying to repair the original components to ripping everything out and turning this into a modern-computer-in-an-old-case project.

In the end he went for an option in between, which we as preservationists can only applaud: he replaced the display with a modern one of the correct size and resolution and built a new custom power supply, keeping the rest of the computer intact as far as possible. [Adalbert] describes the overall process in the video embedded below and goes into lots of detail on his hackaday.io page.

Connecting a modern LCD screen was not as difficult as it might seem: where the old display had an RGB TTL interface with three bits per color, the new one had a very similar system with six bits per color. [Adalbert] made an adapter PCB that simply connected the three bits from the laptop to the highest three bits on the screen. A set of 3D-printed brackets ensured a secure fit of the new screen in the classic case.

For the power supply [Adalbert] took a similar approach. He designed a PCB with several DC/DC converters that fit easily inside the computer’s case, leaving enough space to add a battery. This made the old Toshiba more portable than it ever was — believe it or not, the original T3200SXC could only be used with a mains connection.

Once the laptop was restored to working order, [Adalbert] added a few finishing touches: a sound card and speakers made it suitable as a gaming platform, and a network card gave it rudimentary online capabilities. The end result is a T3200SXC that looks and feels exactly the way it did when it was new, but with a few added features. That’s a really satisfying result: many classic laptop projects add modern computing hardware, or even completely replace the original contents. You might also want to check out [Adalbert]’s unusual 3D printer based PCB manufacturing technique that he used for the new power supply.

Continue reading “Hackaday Prize 2022: Repairing A Vintage Laptop With Modern Components” →