Author: Al Williams

4337 Articles

Kim-1: Memory Problem Resolved

July 10, 2023 by 20 Comments

At the very start of the personal computer revolution, there were relatively inexpensive boards with little more than a CPU, some memory, a display, and switches or a keypad. Some of these had expansion ports meant to allow you to build up, and some were just “trainers” to learn about computers. While you could argue that the Altair fell into this category, it had a case and a proper bus. The computers we are thinking about were usually just on a single board and — with luck — had an edge connector for expansion. Perhaps the most famous of these was the KIM-1 and [Old VCR] shows us how he brought one back to life.

These were highly popular mainly because of the low price of $245 back in 1976. For that price you got a calculator-style keyboard and LED display, 1K of RAM, and 2K of ROM. [Old VCR] has several and noticed that one was developing memory problems.

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A Quick Look At The Hilbert Transform

July 9, 2023 by 30 Comments

While the Fourier transform gets all the attention, there are other transforms that engineers and mathematicians use to transform signals from one form to another. Sometimes you use a transform to make a signal more amenable to analysis. Other times, you do it because you want to manipulate it, and the transform is easier to change than the original signal. [Electroagenda] explains the Hilbert transform, which is often used to generate single-sideband signals.

The math behind the transformation is pretty hairy. However, if you understand the Fourier transformer, you can multiply the Fourier transform by -i sgn(ω), but that isn’t really going to help you much in a practical sense. If you don’t want to bog down in the math, skip immediately to section two of the post. That’s where it focuses more on the practical effect of the transform. You can think of the transform as a function that produces a 90 degree phase shift with a constant gain. For negative frequencies, the rotation is 90 degrees and for positive frequencies, the shift is negative.

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Roll Your Own Simple Tube Tester

July 8, 2023 by 5 Comments

You can easily get carried away when trying to test things. For example, if you want to know if your car is working, you could measure the timing of the ignition and put the car on a dynamometer. Or you could just start it and figure that if it runs and moves when you put it in drive, it is probably fine.

When [Thomas Scherrer] wanted to test some tubes, he made the same kind of assumption. While tubes can develop wacky failure modes, the normal difference between a working tube and a failing tube is usually not very subtle. He made a simple test rig to test tubes at DC and one operating point. Not comprehensive, but good enough most of the time. Have a look at what he did in the video below.

The tester is just a few resistors, a tube socket, and some bench power supplies. Of course, you may have to adapt it to whatever tube you are testing. If we had a lot of tubes to do, we might make the rig a bit more permanent, but for an afternoon of testing, what he has would be fine.

In addition to the power supplies, you’ll need at least one, preferably two, volt meters. He was able to validate his results with a proper tube tester. The results matched up well. While this won’t solve all your tube testing problems, it will give you a quick start.

You can build your own modern tube tester, of course. Or pick up a vintage one. Our favorite one uses punched cards.

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Watch Those 1% Resistors

July 7, 2023 by 54 Comments

Decades ago, electronic components were not as easy to acquire as they are today. Sure, you could get some things at Radio Shack. But you might not have many choices, and the price would be on the high side. TV repair components were another option, but, again, big bucks. Some places sold surplus parts, which could be cheap. These often came from manufacturing runs where a company bought 10,000 components and made 8,000 products. But today, you can order parts inexpensively and get them on your doorstep in a day or, sometimes, even less. Are these inexpensive parts really any good? [Denki Otaku] likes to find out. In a recent video, he checks out some Amazon-supplied 1% resistors to find out how good they are. You can watch his results below.

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Russian Weather Satellite Reuses Name, Yields Images

July 7, 2023 by 13 Comments

Which Russian weather satellite has the name Meteor 2? According to [saveitforparts], pretty much all of them. He showed how to grab images from an earlier satellite with the same name a while back. That satellite, though, met with some kind of disaster, so he’s posted a new video about reading data from the new Meteor 2 and you can watch it below.

The interesting part, we thought, was that the software he’s using, Raspberry-NOAA v2, doesn’t know about this incarnation of the bird which has only been up for a few weeks. That means he had to find a satellite with similar orbital parameters. Eventually, the program will have the setup for this satellite.

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Retrotechtacular: The Nuclear Cruise Ship Of The Future Earns Glowing Reviews

July 7, 2023 by 33 Comments

The average modern cruise ship takes about 250 tons or 80,000 gallons of fuel daily. But can you imagine a cruise ship capable of circling the globe fourteen times before it needed to top off? That was the claim for the NS Savannah, a nuclear-powered cruise ship born out of President Eisenhower’s “Atoms for Peace” initiative.

The ship was a joint project of several government agencies, including the US Maritime Administration. With a maiden cruise in 1962, the vessel cost a little more than $18 million to build, but the 74-megawatt nuclear reactor added nearly $30 million to the price tag. The ship could carry 60 passengers, 124 crew, and over 14,000 tons of cargo around 300,000 nautical miles using one set of 32 fuel elements. What was it like onboard? The video below gives a glimpse of nuclear cruising in the 1960s.

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Hackaday Podcast 226: Ice, Snow, And Cooling Paint In July

July 7, 2023 by 3 Comments

This week, Editor-in-Chief Elliot Williams and Al Williams shoot the breeze about all things Hackaday. We start off with some fond remembrances of Don Lancaster, a legendary hardware hacker who passed away last month. There’s also news about the Hackaday Prize (the tool competition) and a rant about fast computers and slow software, a topic that drew many comments this week.

In the What’s That Sound event, Al proves he’s more of a Star Trek fan than a videogamer. But there were plenty of correct answers, but only one winner: [Wybrandus]. There’s always next week, so keep playing!

Elliot may be dreaming of cooler weather since he talks about ice sculptures, snow measurements, and a paint that can make things cooler. We don’t know what Al is dreaming about, but he is worried about his fuses, and the ins and out of open source licensing.

Along the way, you’ll hear about personal vehicles, sky cameras, and zapping weeds with extreme solar power. As usual, there is an eclectic mix of other posts. What has the Hackaday crew been up to? Field trips! Hear about Dan Maloney’s visit to the SNOTEL network to measure snowfall and a report from Al and Bil Herd’s trip to the Vintage Computer Festival Southwest.

What to read along? The links below will get you started. Don’t forget to tell us what you think in the comments!

Or, download a copy for posterity to file away in your archive.

Where to Follow Hackaday Podcast

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