Author: Al Williams

4296 Articles

A 17th Century Music Computer

April 12, 2025 by 10 Comments

We don’t think of computers as something you’d find in the 17th century. But [Levi McClain] found plans for one in a book — books, actually — by [Athanasius Kirker] about music. The arca musarithmica, a machine to allow people with no experience to compose church music, might not fit our usual definition of a computer, but as [Levi] points out in the video below, there are a number of similarities to mechanical computers like slide rules.

Apparently, there are a few of these left in the world, but as you’d expect, they are quite rare. So [Levi] decided to take the plans from the book along with some information available publicly and build his own.

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GPS Broken? Try TV!

April 11, 2025 by 38 Comments

GPS and similar satellite navigation systems revolutionized how you keep track of where you are and what time it is. However, it isn’t without its problems. For one, it generally doesn’t work very well indoors or in certain geographic or weather scenarios. It can be spoofed. Presumably, a real or virtual attack could take the whole system down.

Addressing these problems is a new system called Broadcast Positioning System (BPS). It uses upgraded ATSC 3.0 digital TV transmitters to send exact time information from commercial broadcast stations. With one signal, you can tell what time it is within 100 ns 95% of the time. If you can hear four towers, you can not only tell the time, but also estimate your position within about 100 m.

The whole thing is new — we’ve read that there are only six transmitters currently sending such data. However, you can get a good overview from these slides from the National Association of Broadcasters. They point out that the system works well indoors and can work with GPS, help detect if GPS is wrong, and stand in for GPS if it were to go down suddenly.

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Audio Effects Applied To Text

April 11, 2025 by 4 Comments

If you are a visual thinker, you might enjoy [AIHVHIA’s] recent video, which shows the effect of applying audio processing to text displayed on an oscilloscope. The video is below.

Of course, this presupposes you have some way to display text on an oscilloscope. Audio driving the X and Y channels of the scope does all the work. We aren’t sure exactly how he’s doing that, but we suspect it is something like Osci-Render.

Does this have any value other than art? It’s hard to say. Perhaps the effect of panning audio on text might give you some insight into your next audio project. Incidentally, panning certainly did what you would expect it to do, as did the pass filters. But some of the effects were a bit surprising. We still want to figure out just what’s happening with the wave folder.

If text isn’t enough for you, try video. Filtering that would probably be pretty entertaining, too. If you want to try your own experiments, we bet you could do it all — wave generation and filtering — in GNU Radio.

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The Jupiter Ace Remembered

April 11, 2025 by 11 Comments

It is hard to imagine that it has been more than four decades since two of the original designers of the Sinclair ZX Spectrum broke off to market the Jupiter Ace. [Nemanja Trifunovic] remembers the tiny computer in a recent post, and we always love to recall the old computers that used TVs for screens and audio tape recorders for mass storage.

One thing we always loved about the Jupiter Ace is that while most computers of the era had Basic as their native tongue, the Ace used Forth. As the post points out, while this may have given it great geek cred, it didn’t do much for sales, and the little machine was history within a year. However, the post also proposes that Forth wasn’t the real reason for the machine’s lack of commercial success.

Why did they pick Forth? Why not? It is efficient and interactive. The only real disadvantage was that Basic was more familiar to more people. Books and magazines of the day showed Basic, not Forth. But, according to the post, the real reason for its early demise was that it was already using outdated hardware from day one.

The Ace provided only 3K of RAM and did not offer color graphics. While this may sound laughable today, it wasn’t totally out of the question in 1978. Unfortunately, the Ace debuted in 1982. There were options that offered much more for just a little less. There is also the argument that as users became less technical, they just wanted to load pre-programmed tapes or cartridges and didn’t really care what language was running the computer.

Maybe, but we did and we can’t help but imagine a future where Forth was the language of choice for personal computers. Given how few of these were made, we see a lot of projects around them or, at least, replicas. Of course, these days that can be as simple as a single chip.

Ask Hackaday: What’s A Sun-Like Star?

April 10, 2025 by 20 Comments

Is a bicycle like a motorcycle? Of course, the answer is it is and it isn’t. Saying something is “like” something else presupposes a lot of hidden assumptions. In the category “things with two wheels,” we have a winner. In the category “things that require gasoline,” not so much. We’ve noticed before that news stories about astronomy often talk about “sun-like stars” or “Earth-like planets.” But what does that really mean? [Paul Gilster] had the same questions, if you want to read his opinion about it.

[Paul] mentions that even textbooks can’t agree. He found one that said that Centauri A was “sun-like” while Centauri B was sometimes considered sun-like and other times not. So while Paul was looking at the examples of press releases and trying to make sense of it all, we thought we’d just ask you. What makes a star like our sun? What makes a planet like our planet?

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Going To The Top With A Raspberry Pi Elevator

April 9, 2025 by 17 Comments

[BorisDigital] was mesmerised by a modern elevator. He decided to see how hard it would be to design his own elevator based on Raspberry Pis. He started out with a panel for the elevator and a call panel for the elevator lobby. Of course, he would really need three call panels since he is pretending to have a three-floor building.

It all looks very professional, and he has lots of bells and whistles, including an actual alarm. With the control system perfected, it was time to think about the hydraulics and mechanical parts to make a door and an actual lift.

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You Shouldn’t Build An X-Ray Machine, But You Could

April 9, 2025 by 18 Comments

Ever wanted your own X-ray machine? Of course you have! Many of us were indoctrinated with enticing ads for X-ray specs and if you like to see what’s inside things, what’s better than a machine that looks inside things? [Hyperspace Pirate] agrees, and he shows you the dangers of having your own X-ray machine in the video below.

The project starts with an X-ray tube and a high voltage supply. The tube takes around 70,000 volts which means you need a pretty stout supply, an interesting 3D printed resistor, and some mineral oil.

The output display? A normal camera. You also need an intensifying screen, which is just a screen with phosphor or something similar. He eventually puts everything in lead and reminds you that this is a very dangerous project and you should probably skip it unless you are certain you know how to deal with X-ray dangers.

Overall, looks like a fun project. But if you want real credit, do like [Harry Simmons] and blow your own X-ray tube, too. We see people build similar machines from time to time. You shouldn’t, but if you do, remember to be careful and to tell us about it!

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