A Breadboard Block For 8-Bit CPUs

October 12, 2020 by 21 Comments

Breadboard CPUs are a fantastic learning experience and require serious dedication and patience. Occasionally, CPU builders eschew their breadboards and fab their design onto a PCB. But this takes away the flexibility and some of the opportunity for learning that breadboard CPUs offer. [c0pperdragon] was doing the same sort of repetitive wiring from project to project as most 8-bit breadboard CPUs use memory, a bus, an IO controller, ROM, and a few other passive components.

Taking a compromise approach, [c0pperdragon] built a PCB that can be used as a building block in his custom CPUs which they have titled “ByteMachine”. A single row of 34 pins offer power, clock, reset, 19 address bus lines, 8 data bus lines, and a ROM selector. This means that the CPUs can fit on a single breadboard and can run faster as the impedance of the breadboard has less effect on the circuit. With 512 KB of RAM and 512 KB of ROM, in a ZIF socket for easy reprogramming, ByteMachine has plenty of space.

One drawback is the lack of IO. There is no dedicated address space as this would require decoding logic between the RAM and the CPU. [C0pperdragon] added a simple 8-bit output register provided by a 74-series logic IC. The data is displayed on 8 red LEDs and can be accessed via pins. Input is accomplished in a similar way with just 8 bits of digital input provided.

[C0pperdragon] has built the 65C02, 65C816,  Z84C00, and the i8088 with the ByteMachine. Each was documented with incredible schematics, pictures, and test programs on GitHub. Next time you’re looking to build a CPU on a breadboard, maybe start with a ByteMachine. In some ways, it might improve your learning experience as it makes the incredible mass of wires we’ve seen on other projects a tad more manageable.

Thanks [Reinhard Grafl] for sending this one in!

Inputs Of Interest: The OrbiTouch Keyless Keyboard And Mouse

October 12, 2020 by 19 Comments

I can’t remember how exactly I came across the OrbiTouch keyboard, but it’s been on my list to clack about for a long time. Launched in 2003, the OrbiTouch is a keyboard and mouse in one. It’s designed for people who can’t keyboard regularly, or simply want a different kind of experience.

The OrbiTouch was conceived of by a PhD student who started to experience carpal tunnel while writing papers. He spent fifteen years developing the OrbiTouch and found that it could assist many people who have various upper body deficiencies. So, how does it work?

It’s Like Playing Air Hockey with Both Hands

To use this keyboard, you put both hands on the sliders and move them around. They are identical eight-way joysticks or D-pads, essentially. The grips sort of resemble a mouse and have what looks like a special resting place for your pinky.

One slider points to groups of letters, numbers, and special characters, and the other chooses a color from a special OrbiTouch rainbow. Pink includes things like parentheses and their cousins along with tilde, colon and semi-colon. Black is for the modifiers like Tab, Alt, Ctrl, Shift, and Backspace. These special characters and modifiers aren’t shown on the hieroglyphs slider, you just have to keep the guide handy until you memorize the placement of everything around the circle.

You’re gonna need a decent amount of desk space for this. Image via OrbiTouch

The alphabet is divided up into groups of five letters which are color-coded in rainbow order that starts with orange, because red is reserved for the F keys. So for instance, A is orange, B is yellow, C is green, D is blue, E is purple, then it starts back over with F at orange. If you wanted to type cab, for instance, you would start by moving the hieroglyph slider to the first alphabet group and the color slider to green.

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Add Creativity To Your BOM: Hack Chat

October 12, 2020 by 2 Comments

Join us on Wednesday, October 14th at noon Pacific for the Harnessing Your Creativity Hack Chat with Leo Fernekes!

You’re sitting at your bench, surrounded by the tools of the trade — meters and scopes, power supplies and hand tools, and a well-stocked parts bin. Your breadboard is ready, your fingers are itching to build, and you’ve got everything you need to get started, but — nothing happens. Something is missing, and if you’re like many of us, it’s the one thing you can’t get from eBay or Amazon: the creative spark that makes innovation happen.

Creativity is one of those things that’s difficult to describe, and is often noticed most when it’s absent. Hardware hacking requires great buckets of creativity, and it’s not always possible to count on it being there exactly when it’s called for. It would be great if you could somehow reduce creativity to practice and making it something as easy to source for every project as any other commodity.

While Leo Fernekes hasn’t exactly commoditized creativity, judging from the breadth of projects on his YouTube channel, he’s got a pretty good system for turning ideas into creations. We’ve featured a few of his builds on our pages, like a discrete transistor digital clock, the last continuity tester you’ll ever need, and his somewhat unconventional breadboarding techniques. Leo’s not afraid to fail and share the lessons learned, either.

His projects, though, aren’t the whole story here: it’s his process that we’re going to discuss. Leo joins us for this Hack Chat to poke at the creative process and see what can be done to remain rigorous and systematic in your approach but still make the process creative and flexible. Join us with your questions about finding the inspiration you need to turn parts and skills into finished projects that really innovate.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 14 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Running Way More LED Strips On A Raspberry Pi With DMA

October 12, 2020 by 18 Comments

The Raspberry Pi is a powerful computer in a compact form factor, making it highly useful for all manner of projects. However, it lacks some of the IO capabilities you might find on a common microcontroller. This is most apparent when it comes to running addressable LED strings. Normally, this is done using the Pi’s PWM or audio output, and is limited to just a couple of short strings. However, [Jeremy P Bentham] has found a way to leverage the Pi’s hardware to overcome these limitations.

The trick is using the Raspberry Pi’s little-documented Secondary Memory Interface. The SMI hardware allows the Pi to shift out data to 8 or 16 I/O pins in parallel using direct memory access (DMA), with fast and accurate timing. This makes it perfect for generating signals such as those used by WS2812B LEDs, also known as NeoPixels.

With [Jeremy]’s code and the right supporting hardware, it’s possible to run up to 16 LED strips of arbitrary length from the Raspberry Pi. [Jeremy] does a great job outlining how it all works, covering everything from the data format used by WS2812B LEDs to the way cache needs to be handled to avoid garbled data. The hack works on all Pis, from the humble Pi Zero to the powerful Pi 4. Thanks to using DMA, the technique doesn’t overload the CPU, so performance should be good across the board.

Of course, there are other ways to drive a ton of LEDs; we’ve seen 20,000 running on an ESP32, for example.

[Thanks to Petiepooo for the tip!]

Ask Hackaday: With Landline Use In Decline, What’s To Be Done With The Local Loop?

October 12, 2020 by 100 Comments

Walking is great exercise, but it’s good for the mind too: it gives one time to observe and to think. At least that’s what I do on my daily walks, and being me, what I usually observe and think about is the local infrastructure along my route. Recently, I was surprised to see a number of telephone company cabinets lying open next to the sidewalk. Usually when you see an open box, there’s a telephone tech right there, working on the system. But these were wide open and unattended, which I thought was unusual.

I, of course, took the opportunity to check out the contents of these pedestals in detail. Looking at the hundreds of pairs of brightly colored wire all neatly terminated and obviously installed and maintained at great expense, I was left wondering why someone would leave such a valuable asset exposed to the elements. With traditional POTS, or plain old telephone service, on the decline, the world may no longer have much use for the millions of miles of copper cable feeding back to telco central offices (COs) anymore. But there’s got to be something this once-vital infrastructure is still good for, leading me to ask: what’s to be done with the local loop?

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HALWOP Recreates Retro Style With The Raspberry Pi

October 12, 2020 by 5 Comments

Modern computers are incredible feats of engineering, but there are many that still yearn for the simpler times. When keyboards clacked and a desktop computer quite literally dominated the top of your desk. There’s a whole community of folks who scratch that itch by restoring vintage computers, but not everyone has the time, money, or skill for such pursuits. Plus, even the most lovingly cared for Apple II isn’t going to help you watch YouTube.

Those who wish to recreate the look and feel of a vintage computer with modern internals will certainly be interested in the HALWOP by [Maz_Baz]. While its 3D printed case isn’t a replica of any one computer, it does draw inspiration from iconic machines like the Apple Lisa and IBM XT. It’s an amalgamation of design ideas that seemed like a good idea circa 1982 or so, with plenty of 90° angles and air vents to go around.

Considering the size of the Raspberry Pi 4 that powers the HALWOP, most of the case is just hollow plastic. But of course, the whole idea depends on it being almost comically large. On the plus side, [Maz_Baz] says you can use one of those empty compartments to hold a Anker PowerCore 26800 battery pack. At least in theory that makes it a “luggable” computer, though good luck trying to move it around.

In addition to the Pi 4 and battery pack, the HALWOP also uses a seven-inch touch LCD and Keychron K2 Bluetooth mechanical keyboard. Since everything is so modular, assembly is about as simple as it gets. Outside of the USB cables that power everything, you just need a long enough ribbon cable to connect the LCD to the Pi.

We know the purists don’t like the idea of a “retro” computer based on the Raspberry Pi, but of course, such projects aren’t about maintaining historical accuracy. They are a way to bridge the gap between modern technology and the unique aesthetics of a bygone era. Designs like the HALWOP allow a new generation to experience a taste of what computing was like in the early days, without giving up the ground that’s been gained in the intervening years.

Spin The Video Track With A Mechanical Flair

October 12, 2020 by 16 Comments

One of the most difficult user interfaces to get right is video editing. It is complex and fiddly with large amounts of precision required even after four or five hours of straight editing. Seeking to bring some of that interface out into the real world, [Zack Freedman] built a mechanical video editing keyboard.

The keyboard in question features popular shortcuts and keys to breeze through different parts of editing. The biggest feature is, of course, the large scrubbing knob, allowing [Zack] to fly through long video with precision. We’ve seen our fair share of mechanical keyboards that aren’t traditional keyboards on Hackaday before, such as this number pad or this macro pad.

One of the unique constraints of this project was the fact that Zack had a deadline of two days. This self-imposed deadline was to help focus the work and drive it towards completion. This meant that it had to be designed in such a way that roadblocks or troublesome features could be designed around or cut out altogether. At its heart, this project is just 14 mechanical switches, 4 potentiometers, and a Teensy to drive it all. It is the design, prototyping, and thought that went into this project that makes it noteworthy. There are plenty of lessons here about how to manage a project’s timeline and advice about how to actually finish it.

Code, STL’s, diagrams, and instructions are all on his GitHub.

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