8 bit

54 Articles

An Arduino From The Distant Past

February 6, 2019 by 20 Comments

Arduinos are a handy tool to have around. They’re versatile, cheap, easy to program, and have a ton of software libraries to build on. They’ve only been around for about a decade and a half though, so if you were living in 1989 and wanted to program a microcontroller you’d probably be stuck with an 8-bit microprocessor with no built-in peripherals to help, reading from a physical book about registers and timing, and probably trying to get a broken ribbon cable to behave so it would actually power up. If you want a less frustrating alternate history to live in, though, check out the latest project from [Marek].

He discovered some 6502 chips (Polish language, Google Translate link) that a Chinese manufacturer was selling, but didn’t really trust that they were legitimate. On a lark he ordered some and upon testing them he found out that they were real 6502s. Building an 8-bit computer is something he’d like to do, but in the meantime he decided to do a project using one of these chips as a general-purpose microcontroller similar to a modern Arduino. The project has similar specs as an Arduino too, including 8kB of RAM memory, 8kB of I/O address space, and various EPROM capabilities. [Marek] went on to build a shield board for it as well, for easy access to some switches and LEDs. It’s a great build that anyone interested in microcontrollers should check out.

Keep in mind that an ATtiny45 has 8 bits like the 6502 but only costs around $1 USD, whereas a 6502 would have cost around $200 in today’s dollars. It’s really only in modern times that we can appreciate the 6502 as a cheap 8-bit microcontroller for that reason alone, but we can also appreciate how it ushered in a computer revolution since competing Intel and Motorola chips cost around six times more before it showed up. They became so popular in fact that people still regularly use them to build retrocomputers of all kinds.

The Embroidered Computer

January 16, 2019 by 5 Comments

By now we’ve all seen ways to manufacture your own PCBs. There are board shops who will do small orders for one-off projects, or you can try something like the toner transfer method if you want to get really adventurous. One thing we haven’t seen is a circuit board that’s stitched together, but that’s exactly what a group of people at a Vienna arts exhibition have done.

The circuit is stitched together on a sheet of fabric using traditional gold embroidery methods for the threads, which function as the circuit’s wires. The relays are made out of magnetic beads, and the entire circuit functions as a fully programmable, although relatively rudimentary, computer. Logic operations are possible, and a functional schematic of the circuit is also provided. Visitors to the expo can program the circuit and see it in operation in real-time.

While this circuit gives new meaning to the term “wearables”, it wasn’t intended to be worn although we can’t see why something like this couldn’t be made into a functional piece of clothing. The main goal was to explore some historic techniques of this type of embroidery, and explore the relationship we have with the technology that’s all around us. To that end, there have been plenty of other pieces of functional technology used as art recently as well, but of course this isn’t the first textile computing element to grace these pages.

Thanks to [Thinkerer] for the tip!

 

Chiptunes On A Solar Panel

April 6, 2018 by 16 Comments

With its vintage sound, there’s no mistaking the unique 8-bit sound of video games from the 80s and 90s. It became so popular that eventually sparked its own genre of music known as “chiptune” for which musicians are still composing today. The music has some other qualities though, namely that it’s relatively simple from a digital standpoint. [Robots Everywhere] found that this simplicity made it perfect as a carrier for wireless power transmission.

The project acts more like a radio transmitter and receiver than it does a true wireless power transmitter, but the principle is the same. It uses a modified speaker driver and amplifier connected to a light source, rather than to a speaker. On the receiving end, there is a solar panel (essentially a large photodetector) which is wired directly to a pair of earbuds. When the chiptune is played through the amplifier, it is sent via light to the solar panel where it can be listened to in the earbuds.

The project is limited to 24,000 bytes per second which is a whole lot more useful than just beaming random audio files around your neighborhood, although that will still work. You can also use something like this to establish a long-distance serial link wirelessly, which can be the basis of a long distance communications network.

Thanks to [spiritplumber] for the tip!

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An Amstrad PCW For The 21st Century

October 30, 2017 by 11 Comments

If you were a computer-mad teen in the late 1980s, you were probably in the process of graduating from an 8-bit machine to a 16-bit one, maybe an Amiga, or an Atari ST. For the first time though you might not have been the only computer owner in your house, because there was every chance your parents might have joined the fun with a word processor. Maybe American home offices during this period might have had PC clones, but for Brits there was every chance that the parental powerhouse would have been an Amstrad PCW.

Amstrad were the masters of packaging up slightly outdated technology for electronic consumers on a budget, and the PCW was thus a 1970s CP/M machine for the 1980s whose main attraction was that it came with monitor and printer included in the price. [James Ots]’ parents had one that interested him enough that  he has returned to the platform and is documenting his work bringing it up to date.

It was the most recent progress in booting into CP/M from an SD card by hijacking the printer ROM that caught our eye, but reading all the build logs that is only the tip of the iceberg. He’s connected another monitor, made a joystick port and a soundcard, and added a memory upgrade to his PCW. Most of these machines would have only been used with the bundled word processor, so those are real enhancements.

We’ve featured quite a few projects involving Amstrad’s CPC home computers, such as this one with a floppy emulator. Amstrad are an interesting company for followers of consumer electronics of the ’70s and ’80s, they never had the out-there tech wackiness of their great rival Sinclair but their logo could be found on an astonishing variety of appliances. The “AMS” in Amstrad are the initials of the company founder [Alan Sugar], who is rather better known in 2017 as the British host of The Apprentice. It is not known whether he intends to lead the country.

This 6502 Computer Project Is A Work Of Art

August 21, 2017 by 30 Comments

If you were a home constructor in the 8-bit era, the chances are that if you built a microcomputer system you would have ended up with a bare printed circuit board and a terminal. If you were on a budget you might have had a piece of stripboard as well, or maybe even wire-wrap. Beautiful cases were out of reach, they came with expensive commercial computers that were not the preserve of impoverished hobbyists.

Constructing an 8-bit machine in 2017 is a much easier process, there are many more options at your disposal. There is no need to make a bare PCB when you have a 3D printer, and this is demonstrated perfectly by [Dirk Grappendorf]’s 6502 computer project. He’s built from scratch an entire 6502 system, with a text LCD display, and housed it in a case with a keyboard that would put to shame all but the most expensive commercial machines from back in the day.

But this is more than just a hobby project thrown together that just happens to have a nice case, he’s gone the extra mile to the extent that this is professional enough that it could have been a product. If you’d been offered [Dirk]’s machine in 1980 alongside the competitors from Apple and Commodore, you’d certainly have given it some consideration.

We’ve seen retrocomputers too numerous to mention on these pages over the years, so if they are your thing perhaps it’s time to draw your attention to our VCF West reports, and to our reviews of computer museums in Germany, and Cambridge or Bletchley, UK.

Thanks [Colin] for the tip.

8-bit Computer For On-The-Go Programming

June 16, 2017 by 13 Comments

If there was one downside to 8-bit computers like the Commodore 64, it’s that they weren’t exactly portable. Even ignoring their physical size, the power requirements would likely have required a prohibitively large power bank of some sort to lug around as well. The problem of portability has been solved since the late ’70s, but if you still want that 8-bit goodness in a more modern package you’ll have to look at something like retrocomputing madman [Jack Eisenmann]’s DUO Travel computer.

The computer is based around the ubiquitous ATmega328 which should make the ease at which it is programmable apparent. Even so, its 14-button keypad makes it programmable even without another computer. While it has slightly less memory than a standard C-64, it’s still enough for most tasks. And, since its powered by a 9-volt battery it doesn’t require any external power sources either.

The most impressive part of the build, however, is the custom programming language specifically tailored for this platform. After all, a 14-button keypad wouldn’t be a great choice if you had to program in Perl or C all the time. There is some example code on the project page for anyone interested in this specific implementation. While it’s not the most minimal computer [Jack] has ever built, it’s certain to be much more practical.

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Homemade Computer From 1970s Chips

June 16, 2017 by 39 Comments

Sometimes it starts with a 555 timer and an op-amp. Other times with a small microcontroller. But the timing’s not so great and needs a dedicated timing crystal circuit. And maybe some more memory, and maybe the ATtiny should be swapped out for some 74LS-series chips. And now of course it needs video output too. Before you know it, you’re staring at a 40-chip computer that hearkens back to a simpler, yet somehow more complex, time of computing. At least that’s where [Marcel] is with his breadboard computer based on 1970s-era chips.

For what it does, this homebrew computer is relatively simple and straightforward. It gets 8 bits of processing power from 34 TTL chips. Another 6 round out the other features needed for the computer to operate. It is capable of rendering 64 colors in software and has more than enough memory for a computer of this sort. So far the only recurring problem [Marcel] has had has been with breadboard fatigue, as some of the chips keep popping out of the sockets.

This is a great project for anyone interested in homebrew or 8-bit computing, partially because of some of the self-imposed limitations that [Marcel] imposed on himself, like “only chips from the 70s”. It’s an impressive build on its own and looks to get much better since future plans call for a dedicated PCB to solve the issue with the worn-out breadboards. If you’re already invested in a project like this, don’t forget that the rabbit hole can go a little deeper: you can build a computer out of discrete transistors as well.