Back in the 70’s when computers were fairly expensive and out of reach for most people, [David Hagelbarger] of Bell Laboratories designed CARDIAC: CARDboard Illustrative Aid to Computation. CARDIAC was designed as an educational tool to give people without access to computers the ability to learn how computers work.
The CARDIAC computer is a single-accumulator single-address machine, which means that instructions operate on the accumulator alone, or on the accumulator and a memory location. The machine implements 10 instructions, each of which is assigned a 3-digit decimal opcode. The instruction set architecture includes instructions common to simple Von Neumann processors, such as load, store, add/subtract, and conditional branch.
Operating the computer is fairly simple–the cardboard slides guide you through the operation of the ALU and instruction decoder, and the flow chart shows you which stage to go to next. The program counter is represented by a cardboard ladybug which is manually moved through the program memory after each instruction completes.
Even though the CARDIAC is dated and very simplistic, it is still a useful tool to teach how microprocessors work. Although modern processors include multi-stage pipelines, finely-tuned branch predictors, and numerous other improvements, the basic principles of operation remain the same.
In case you haven’t been reading Hackaday for the last few weeks, we just had an amazing 10th anniversary party in Pasadena this weekend, full of workshops, talks, and a party that reportedly went until four in the morning. One of the amazing hackers we invited to give a talk was [Quinn Dunki], creator of Veronica, the modern 6502 computer stuffed inside an old radio.
We first saw Veronica a few years ago, but [Quinn] figures she’s been building her computer for about five years now. She’s a software developer by trade that decided one day to dip her toes into the murky seas of hardware development and build a computer from the ground up. She chose the 6502 as the brains of her contraption, laid out everything on single-sided boards etched in a kitchen, and connected everything with a backplane. Right now it has a USB keyboard, (technically a PS/2 keyboard with a USB plug), NES controllers, a VGA display, and a monitor and Pong in ROM. [Quinn]’s goal was to build a computer that could program itself, and after five years, she’s accomplished that goal.
[Quinn] admits her software background was responsible for a few of her admittedly bad design choices; the VGA is generated by an ATMega microcontroller, working under the theory that if she could clock the micro fast enough, she could do VGA. She now believes an FPGA would have been a better choice for video output, but now that the video circuit is done, she probably won’t revisit that problem.
There is one thing missing from Veronica, and something that [Quinn] will be working on in the future: mass storage. Right now every program Veronica can run is either stored in ROM or entered via the keyboard. A hard drive is the next problem to solve, either with an SD card, or a Compact Flash or IDE hard drive.
Sometimes you come across a build so far along you wish you could go back and enjoy it just a bit at a time. This C65 build is so far along, it’s like binge watching a retro computer build. One that never actually existed.
Okay, that’s admittedly a bit rash. But technically the C65 (successor to the Commodore C64) never saw its way through development. A good place to start looking in on the build is from the second post way back in March. The FPGA-based project is already looking promising with proof-of-concept display tests. Are we the only ones surprised by the 1920 native display resolution?
The Wikipedia page on the C65 gives a good idea of how awesome this would have been back in the day had it actually made it to market. We suppose it joins the Commodore lists of would-haves and should-haves with the likes of the C128.
Like parents standing on the porch waiting to see their children off to their first day of school we waited for what comes next in a release to production. Among our children: The C116 ($49 Sinclair killer), the C264 ($79 office computer), and the V364 – The computer with an interactive desktop that could speak (courtesy of [John Fegans] who gave us the lion’s share of what made the C64 software great).
Something happened then, and by something I mean nothing. Nothing happened. We waited to assist in production builds and stood ready to make engineering change notices, and yet nothing happened. It was around this time that [Mr. Jack Tramiel] had left the company, I know why he left but I can’t tell due to a promise I made. Sadly, without [Tramiel’s] vision and direction the new product releases pretty much stopped.
Meanwhile in Marketing, someone came up with the idea to make the C264 more expensive so that they could then sell it for a prohibitively high price in. They changed the name, they told us to add chips, and they added software that (at best) wasn’t of interest to the users at that price. They wanted another C64, after all it had previously been the source of some success. Meanwhile the C116 and the V364 prototypes slowly melded into the random storage of a busy R&D lab. We literally didn’t notice what had happened; we were too busy arguing against abominations such as the C16 — a “creation” brought about by a shoving a TED board into a C64 case (the term inbred came to mind at the time).
Michigan Tech was throwing out a bunch of old electronic equipment, and [Evan] snagged quite a gem: a UHF signal generator built by Hewlett Packard circa 1955. He stripped all of the remaining electronics out of the case, but kept the slide-out trays and the front instrument panel to create this antique-looking file server.
The bottom tray was where the bulk of the electronics were housed, and since widespread adaptation of transistors for electronics wasn’t common at the time (the first silicon transistor wasn’t made until 1954), the original equipment was all vacuum tubes. This meant that there was just enough space for a motherboard, heat sink, and a couple of power supplies.
The hard drives are held in custom housings in the top portion of the case. The real magic, however, is with the front display panel. [Evan] was able to use the original meters, including a display for “megacycles” which is still technically accurate. The meters are driven by a USB-to-serial cable and a python script that runs on the server.
The antique case is a great touch for this robust file server. Make sure to put it in a prominent place, like next to your antique tube radio.
Reddit user [popson] just finished off this impressive monitor mount build. Designed completely in Sketchup, it’s adjustable and will fit monitors from 20″ to 27″.
While designing it they stuck with standard material sizes, and it makes use of a lot of cold rolled steel — box tube, angle, and tube. Wide aluminum channel provides the adjust-ability for various monitor sizes, and standard VESA monitor mounting brackets guarantee monitors will fit.
There’s a lot of welding involved, but like [popson] says, he’s no pro — it’s not that hard to do. Once everything was done, they painted it glossy black to protect it from rusting.
The adjustment knobs are even home-made, cut from a wooden plank using a hole saw, sanded, and varnished.
He’s even added RGB LED light strips onto each of the monitors for a fully immersed gaming experience.
Sometimes changing your computer mouse can be uncomfortable for a while until you get used to the replacement. It may also take some time to get used to new features or the lack of features the new mouse has. [Jon] bought an awesome wireless mouse that he really likes but it is missing one critical feature: rapid fire for gaming. He previously modded his old wired mouse to have a rapid fire button using a 555 timer. That worked fine as the mouse ran off the USB’s 5 volts, and that’s the voltage the 555 timer needed. The new wireless mouse has a 1.5 volt battery and can not support the 555 timer. What’s a gamer to do?
[Jon] searched around the ‘net but could not find any wireless rapid fire mods. Eventually, he did find a low-voltage variation called the LMC555 and ordered a few for his project. The new wireless mouse was taken apart in order to find out how the mouse buttons work. In this case, the signal pin is pulled low when the mouse button is pushed. Now that it is known how the mouse button works, just a couple of resistors, a capacitor, an NPN transistor and a push button switch are all that are necessary to finish up this mod. When the push button is pressed, the LMC555 timer activates the transistor in order to ground the mouse button signal pin. This happens to the tune of 1236 times a minute! That is a lot of rapid firing.
The few components were soldered up neatly and packed into the limited spare area inside the mouse. A hole drilled in the side of the mouse’s housing holds the new rapid fire push button in an ergonomically pleasing location.
Earlier, we mentioned [Jon] has done this mod before on a wired mouse. He learned about that project here on Hackaday. Check it out if your wired mouse is craving a rapid fire button.