brainwagon

Yep, been spending some time thinking about homebrew computer architectures. I’ve also been reading Gordon Bell’s Computer Engineering, pondering some of the older and earlier computing architectures. Caxton Foster’s Computer Architecture describes a simple computer architecture called “Blue”, which has only 16 instructions, and uses only direct addressing. It’s a pretty primitive machine (more like […]

Just another link to inspire me in my glacial moves toward designing a CPU of my own: The D16/M is a general-purpose, stored-program, single-address, 16-bit digital computer using two’s complement arithmetic. It manages subroutine calls and interrupts using a memory stack. The processor may directly address 64K words of memory or I/O. Its timing and […]

My blog may be unavailable for a short time today as I perform some needed upgrades. If all goes well, any down time should last only a few minutes. Don’t despair! I’ll be back shortly. Addendum: Upgrade seemed to go smoothly and without any problems. If you are experiencing any strangeness, try refreshing this page. […]

I haven’t had all that much time to work on the Gameduino between holidays, visiting family and a business trip, but I have been meaning to put together a simple “button box” for the Gameduino, basically consisting of just four buttons (L/R/thrust/fire). I suppose I could have included hyperspace too, but 4 buttons was sufficient […]

I’ve seen lots of bashing of Michael Bay and his movies this weekend. Amongst the blogging world, there seems to be almost universal contempt the flashy, soul-less combination of flashy cars and collagen injected supermodels. And yet his latest release Transformers: Dark of the Moon just claimed the all time Independence Day record, amassing 156 […]

I was bored, and feeling stupid. So, I was scanning around looking for numbers stations. And, if you look, you shall find. Here’s one transmitting Morse code using AM, on 5.898Mhz. Not sure what this one is, but it’s not uncommon to find numbers stations on that frequency. Numbers Station on 5.898 Mhz, Morse Code […]

Over at the tymkrs blog, they’ve been learning a bit about RTTY as a digital mode, but I found their description a bit theoretical. I’d describe radio teletype (RTTY) as a popular digital mode, particularly among contesters. It encodes text as a stream of five bit code words using a system known as Baudot, and […]

I was digging around trying to find some software to help me design a magnetic loop antenna for use on VLF frequencies. I stumbled across this page, which provided a lot of interesting insights, as well as a Spice model to help you understand how they work. Magnetic Loop Antenna Theory The article clarified something […]

Dieter Muller has an amazingly interesting collection of interesting ideas about building homebrew cpus with TTL logic. I’m sure to old school logic designers, most of these are old hat, but to the nearly crazed home experimenter, they are quite illuminating. His hints on ALU design are what brought me to the site, so I’m […]

It’s been quite some time since I’ve hunted for any beacons, and I’ve never really payed much attention to HF pirate beacons. Typically these are solar powered beacons which are deployed somewhere in the deserts of the American Southwest, and charge during the day and transmit simple sequences of Morse characters once the sun goes […]

It was a convenient time to renew my blog’s hosting plan over the weekend, so I made my payment and you can be assured that the brainwagon blog (which as many as a dozen of you inexplicably read) will be available for another 12 months. It got me thinking about the many bloggers I know […]

I spent most of the week in New York, so Field Day snuck up on me without me making any serious plans. But since Jeri has been homebrewing her own SDR I’ve been thinking more about that, and thought that I would dust off my SDR-IQ receiver and at least make some recordings of the […]

In a previous blog post about a year ago, I pointed you at Jack Eisenmann’s 4 bit computer built from TTL chips. It was cool, made entirely on breadboards tucked away inside a big plastic container. Or, I used to think it was cool, until I saw what he’s been up to: an 8 bit […]

Anyone who has seen my projects on the Atari 2600 might reasonably conclude that I have a thing for retro computing. The saying goes “it is no virtue to do with more, what can be done with less” and I can’t think of someone whose projects have embodied that more than demo coder Linus Akesson […]

Most of the websites that I link to are related to specific topics or projects. But every once in a while, you find one that has a bunch of good stuff that matches some of your esoteric interests, and you wonder how one person could do it all. Inspired by Jeri Ellsworth’s latest video showing […]