Dicom to weird animated GIF via Python

Every now and then, having some coding skills turns out to be useful in the most unexpected ways. In support of a creative project, I need to be able to convert some image files. But these aren’t your normal, run-of-the-mill snapshots. They are images captured during CT and MRI scans. This being France, your medical data is regarded as your… Read more »

Repairing a BBC Master #3: Power checks

Now that we know the sickly BBC Master’s power supply is okay, it’s time to check whether that power is getting to all the chips on the board. Luckily, the schematics help us here in more ways than one. On the first page is a table of all the ICs with pin numbers for their VCC and GND connections. I… Read more »

Prints, posters and more

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In my other life, I’m a photographer. In fact, I’ve been taking pictures since I was a teenager and my degree is in film & photography. It’s deep in my DNA. Maybe being a geek helps. Photography is a combination of aesthetics and technology – now more than ever. Most of my work centres around landscape, the environment and travel,… Read more »

Zolatron: RTC, SRAM and SD board

After my fun with real-time clock chips (here and here) I figured it was time to add one to the Zolatron 64. But there was a catch. The previous experiments had involved microcontrollers with built-in SPI capabilities. That was something the Zolatron sadly lacked. Luckily, someone else has already come up with a solution. The 65SPI project by Daryl Rictor… Read more »

Repairing a BBC Master #2: Basic steps

First, do no harm. Second, check the voltages. That’s how the Hippocratic Oath starts when adapted for electronics. If the device under test is not getting the proper power supply, then you can’t reasonably expect it to work. But there’s something I wanted to check, even before I apply power, and this turned out to be a learning opportunity. With… Read more »

Adventures with real-time clocks – part 2

The story so far: I’d been tinkering with an MCP795W20 real-time clock (RTC) chip and having a frustrating time of it. Weird things were happening. It seemed very finicky. I’d put part of the problem down to using a breadboard (still think I’m not entirely wrong about that). It turns out, however, that the biggest problem was my own stupidity…. Read more »

Repairing a BBC Master: #1 – plan of attack

So my poor Acorn BBC Master Turbo is sick … again. And I feel a little bit responsible. Quick recap: the Master developed a problem some years ago. This was ‘fixed’ when a very generous person donated a motherboard from his machine. I never did find the cause of the problem. Since then, however, the machine has spent a lot… Read more »

Adventures with real-time clocks – part 1

So I decided that I’d like to add a real-time clock (RTC) to the Zolatron project because … why not? Should be easy, I thought. Lots of people have done it. All I need is the right chip. Maybe that’s where I made my mistake. As it turned out, for some reason, I already own three copies of the Microchip… Read more »

Now available on Mastodon

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As it happens, I set up my Mastodon account some time ago, long before Elon Musk’s ego decided it needed a new toy to destroy. I just hadn’t used it much because … well, I didn’t use Twitter much either. However, all the kerfuffle over Twitter has prompted me to look again at Mastodon. You can find/follow me at: @speculatrix@mastodon.online… Read more »

Zolatron 64 6502-based homebrew computer: mission accomplished

Okay, so I’m going to call it. This project is finished. Well, not finished exactly. No project is ever finished. You can always do more. And so it is with the Zolatron – I have ideas and plans that will keep me happily tinkering away for years. But I’ve met my main objective – which is to better understand how… Read more »

Reviving a Centurion

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Something that has been providing me with plenty of inspiration for my Zolatron homebrew project lately is the Usagi Electric YouTube channel, particularly the series of videos on restoring a Centurion mini computer. For one thing, it’s comforting to know there are people more nuts than you. I can just image the reaction I’d get from my More Significant Other… Read more »

What’s better than a 6502 homebrew computer?

Yep, you guessed it – two of them. One of the side effects of ordering PCBs from the likes of JLCPCB is that you have to order at least five copies of each board. This doesn’t quite mean that I have enough PCBs to make five Zolatron 64s. For one thing, each of the machines above uses two of the… Read more »

Zolatron 64: Writing an OS for a 6502 homebrew computer

I’ve said it before and I’ll say it again: I have no idea how you write an operating system. Even though I’ve sort-of written one. I’m calling it ZolOS. The Zolatron 64 6502 homebrew computer project started as idle curiosity that just got out of hand. I figured I’d be happy if I could get as far as writing ‘Hello… Read more »

Zolatron 64: memory expansion

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Things are continuing apace with the Zolatron 64 6502 homebrew computer. In fact, progress has been so rapid that I haven’t really had much time to talk about it. So here’s a quick refresher – and details of the new memory expansion board. Serial killer The 6551 ACIA serial board is dead. Well, it’s not dead, but I’ve stopped using… Read more »