Author: Al Williams

4469 Articles

Carbon Fiber With 3D Printing

September 25, 2023 by 31 Comments

[Thomas Sanladerer] wanted to make 3D prints using carbon fiber and was surprised that it was fairly inexpensive and worked well, although he mentions that the process is a bit intense. You can learn what he found out in the video below.

He used an advanced PLA that can endure more temperature than normal PLA. That’s important because the process uses heat and the carbon fiber resin will produce heat as it cures. The first step was to print a mold and, other than the material, that was pretty straightforward.

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The Reverse Oscilloscope

September 25, 2023 by 17 Comments

Usually, an oscilloscope lets you visualize what a signal looks like. [Mitxela]’s reverse oscilloscope lets you set what you want an audio waveform to look like, and it will produce it. You can see the box in the video below.

According to [Mitxela] part of the difficulty in building something like this is making the controls manageable for mere mortals. We really like the slider approach, which seems pretty obvious, but some other controls are a bit more subtle. For example, the interpolation control can create a squarish wave or a smooth waveform, or anything in between.

This is sort of an artistic take on an arbitrary waveform generator but with a discrete-panel user interface. The device contains a Teensy, a Raspberry PI Pico, a 16-bit ADC, and an external DAC. The Pico is little more than an I/O controller, reading the user interface and transmitting it on a serial port.

The outside construction looks excellent (we assume the tape is temporary). The inside is a bit messier, but still nicely done. There are many photos of the construction and details of problems along the way with 12-bit ADCs and power supply experiments.

Of course, if you don’t need the user interface, you can go crazy with waveform generation. We did our own similar project, but you could draw your waveforms on the PC instead of sliders.

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Bill, Steve, And Gary… Computer Pioneers

September 25, 2023 by 52 Comments

If you ask your neighbor who Bill Gates or Steve Jobs is, they’d probably know. But mention Gary Kildall, and you are likely to get a blank stare unless you live next door to another Hackaday reader. [Al’s Geek Lab] has a great three-part documentary on Gary Kildall who, in case you didn’t know, was the man behind CP/M, a very influential operating system in the early days of computing and one that set the stage for the PC revolution.

You probably know the folktale that when IBM was looking for an operating system, Bill Gates took the meeting, and Gary Kildall went surfing instead. But like most capsule histories, there is plenty more to the story, and it isn’t as simple as people make it out.

We forget, sometimes, how innovative Digital Research — Kildall’s company — was for the time. We think of CP/M as the venerable CP/M 2.2, which was fine. But there was multitasking CP/M and GEM — a precursor to the graphical user interface found everywhere today. Sure, it looks antiquated now, but it was light years in front of everyone else.

If you watch the whole series, you’ll learn that the IBM story isn’t totally apocryphal, but the truth is much different. Kildall didn’t want the IBM deal, and for what seemed like good reasons at the time. Of course, Gates negotiated a deal with IBM that would build a huge company, so it is easy to look back and say that not taking the deal was a mistake, but we would have probably made the same decision as Kildall at that time.

This isn’t the first time we’ve wondered what a world where CP/M won would have looked like. If you want to look inside CP/M, you can. Of course, it still powers many retrocomputers and even has some surprising clones.

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Saving A Scope From The Dumpster

September 24, 2023 by 9 Comments

If you read Hackaday, you probably get the title of [SunEstra’s] post: A Casual Date with the Dumpster. Many great hacking projects start with finding one man’s trash. This June, [SunEstra] rescued an old Tektronix 2465B oscilloscope, which appeared to be in good shape. Why we never find four-channel 400 MHz scopes in the dumpster is hard to explain, but we are still happy for him, if not a little jealous.

As you might expect, powering up the scope was a disappointment. Relays clicked. Lights flashed. But no display. Adjusting the grid bias on the CRT brought up the display, but it also brought up something else: an error message.

The scope was complaining of “test failure 05-40.” A look through the manual reveals that is “positive level too positive.” Huh. Too much of a good thing, we guess. The test checks the A5 board, so a visual inspection there was the first step.

Unsurprisingly, there were electrolytic capacitors leaking electrolyte. This is, apparently, a well-known problem with this scope. Replacing the electrolytics with some similar tantalum capacitors. In a few cases, the corrosion had eaten pads off the PCB, and some were damaged during the removal. It took a little ingenuity to connect the new parts on the board.

The result? A working scope. Maybe the scope will help repair the next thing that comes out of the dumpster. Sometimes, the best dumpster dives involve intercepting the gear before it hits the dumpster. We keep hoping to run into one of these on the curb (the linked post seems dead, but the video is still there).

Getting Geared Up For Home Powder Coating

September 24, 2023 by 17 Comments

[Blondihacks] wanted to do powder coating for a model train without a lot of special equipment. She started with an Eastwood kit that runs about $230. Depending on the options, you can get the gun by itself for between $110 – $170. However, you will need more than just this kit. You can see how [Blondihacks] used the kit in the video below.

The idea behind powder coating is simple: an electrostatic charge attracts a powder — usually some polymer — and makes it stick to an item. Then heat or UV light turns the powder into a hard finish much tougher than paint. Powder coating can be thicker than paint and doesn’t run, either.

The gun requires a small air compressor, and you need an electric oven, which could be a toaster oven. It probably shouldn’t be an oven you plan to use for food. It should also be in a well-ventilated area, plus you’ll want a respirator or dust mask. [Blondhacks] used a portable paint booth so as not to spew powder everywhere, which looked nice, although you could just use a big cardboard box. A custom jig to hang the parts while spraying, and she was ready to go.

If you are on a budget, by the way, you can get a kit from Harbor Freight for a bit less. It probably has fewer accessories, and we don’t know how it compares, but it is an option for much less money. Either way, you need a small air pressure regulator, and you also need a dryer and a filter for the air because you need dry and clean air so as not to contaminate the powder.

The part is grounded, and the gun charges the powder as it sprays. Once coated, you stick the part in the oven for about 20 minutes. The results look good and, compared to a painted part, the coating was super tough. For intricate parts, you can heat the part and then dip it in fluid-like powder. If you prefer to stick to regular powder coating, we have some tips.

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That’s Not A Junker… That’s My Generator

September 22, 2023 by 104 Comments

If you live somewhere prone to power outages, you might have thought about buying a generator. The problem is that small generators are cheap but — well — small. Big generators are expensive. [Jake von Slatt] had an idea. He has a “yard car” which we thought might be a junk car but, instead, it is an old car he uses to drive around his yard doing tasks. It has a winch and a welder. Now it has a big generator, too. You can follow the project in the three videos found below.

The project started with a scrap generator with a blown motor. Of course, the car has a motor so — in theory — pretty simple. Remove the generator from the motor and graft it to the car’s motor. But the details are what will kill you.

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Ham Radio Mini Beam

September 22, 2023 by 6 Comments

Years ago, ham radio operators more often than not had land, and usually there weren’t any restrictions on what kind of antenna they could erect on that land. These days you are more likely to live with less or no land, and even if you do own property, you might have restrictions that prevent you from putting up any kind of visible antenna.

But even if that’s not the case, you might not have room for an old-fashioned “tri-bander” or “cubical quad” that the hams of old preferred. [Waters & Stanton] has a 65-year-old design for a miniature beam that he explains, and it produces a good beam antenna in a reduced amount of space. You can watch a video about the antenna below.

The design uses a doublet — a dipole fed with a balanced line and tuned at the feed point. A 22-foot doublet can cover 20 meters down to 10 meters without traps. Adding a director and reflector element provides directionality and gain. A unique arrangement allowed a 12-foot boom to support multiple elements on some bands by introducing a central coil on some elements. For example, the director is tuned to 15 meters using a center coil. But the coil is shorted with a 10 meter quarter stub that acts as a short on that band. You can see a complete explanation in the video.

We were hoping to see a build and some on-the-air testing, but, apparently, that is left as an exercise for the viewer. We imagine that 65 years ago, you’d use a grid dip oscillator to tune the stubs. Today, an antenna analyzer would do the job easily.

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