CP/M 8266

March 25, 2017 by 81 Comments

Hands up if you’ve ever used a machine running CP/M. That’s likely these days to only produce an answer from owners of retrocomputers. What was once one of the premier microcomputer operating systems is now an esoteric OS, a piece of abandonware released as open source by the successor company of its developer.

In the 1970s you’d have seen CP/M on a high-end office wordprocessor, and in the 1980s some of the better-specified home computers could run it. And now? Aside from those retrocomputers, how about running CP/M on an ESP8266? From multi-thousand-dollar business system to two-dollar module in four decades, that’s technological progress.

[Matseng] has CP/M 2.2 running in a Z80 emulator on an ESP8266. It gives CP/M 64K of RAM, a generous collection of fifteen 250K floppy drives, and a serial port for communication. Unfortunately it doesn’t have space for the ESP’s party piece: wireless networking, but he’s working on that one too. If you don’t mind only 36K of RAM and one less floppy, that is. All the code can be found on a GitHub repository, so if you fancy a 1970s business desktop computer the size of a postage stamp, you can have a go too.

There’s something gloriously barmy about running a 1970s OS on a two-dollar microcontroller, but if you have to ask why then maybe you just don’t understand. You don’t have to have an ESP8266 though, if you want you can run a bare-metal CP/M on a Raspberry Pi.

Bad Thermal Design And Burning Down The House

March 25, 2017 by 31 Comments

Control boards for 3D printers are a dime a dozen on the usual online marketplaces, and you usually get what you pay for. These boards can burn down your house thanks to a few terrible design choices. [Scott Rider] aka [Crow] took a look at the popular Melzi board, and what he found was horrifying. These boards overheat right at the connector for the heated bed, but the good news is these problems are easily fixed.

The Melzi board has a few problems with its PCB design. The first and most glaring issue is the use of thermals on the pads for the heated bed connector. In low-power applications, thermals — the method of not connecting the entire top or bottom layer to a hole or pad — are a great idea. It makes it easier to solder, because heat isn’t transmitted as easily to the entire copper layer. Unfortunately, this means heat isn’t transmitted as easily to the entire copper layer. In high-power applications, like a connection to a heated bed, these thermals can heat up enough to melt a plastic connector. Once that happens, it’s game over.

Other problems were found in the Melzi board, although you wouldn’t know it just by looking at the Eagle file of the PCB. [Scott]’s Chinesium Melzi board used 1-ounce copper, where 2-ounce copper would be more appropriate. The connector, too, should be rated above the design power loading.

[Scott] made a few tweaks to the board and also added a tiny DS1822Z temperature sensor to the high-current area of his version of a Melzi. Imagine that, 3D printer electronics with a temperature sensor. Slowly but surely, the state of 3D printer electronics is clawing its way to the present.

MIDI Drawings Paint With Piano Keyboards

March 25, 2017 by 9 Comments

Musician [Mari Lesteberg] is making music that paints pictures. Or maybe she’s making pictures that paint music. It’s complicated. Check out the video (embedded below) and you’ll see what we mean. The result is half Chinese scroll painting, and half musical score, and they go great together.

Lots of MIDI recorders/players use the piano roll as a model for input — time scrolls off to the side, and a few illuminated pixels represent a note played. She’s using the pixels to paint pictures as well: waves on a cartoon river make an up-and-down arpeggio. That’s a (musical) hack. And she’s not the only person making MIDI drawings. You’ll find a lot more on reddit.

Of course, one could do the same thing with silent pixels — just set a note to play with a volume of zero — but that’s cheating and no fun at all. As far as we can tell, you can hear every note that’s part of the scrolling image. The same can not be said for music of the black MIDI variety, which aims to pack as many notes into a short period of time as possible. To our ears, it’s not as beautiful, but there’s no accounting for taste.

It’s amazing what variations we’re seeing in the last few years on the ancient piano roll technology. Of course, since piano rolls are essentially punch-cards for musical instruments, we shouldn’t be too surprised that this is all possible. Indeed, we’re a little bit surprised that new artistic possibilities are still around. Has anyone seen punch-card drawings that are executable code? Or physical piano rolls with playable images embedded in them?

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Replica Fallout Terminal

March 25, 2017 by 28 Comments

If you’ve played Fallout 4, you’re familiar with the wall-mounted terminals in the game. They’ve got a post-apocalyptic aesthetic and the glowing green screen that calls out to anyone that grew up with computers and hacker movies from the 80s and 90s. Remember the first time you set your command line text to green? Don’t be embarrassed, we were all young once.

[PowerUpProps] liked the Fallout terminal so much they developed a replica. It’s a build that leans heavily on maker standards, a Raspberry Pi and 3D printing form the basis of the terminal. With ready access to such powerful tools, it makes starting such a project much more approachable. The key to the success of this build is the fine attention to detail in the finishing – the paint job looks incredible, and when photographed appropriately, it could be mistaken for the real thing an in-game screenshot.

An interesting touch is the use of a dark green acrylic window in front of the LCD, which gives the display a tinted hue. We’d like to see this compared with a clear glass window with a classic fishbowl curve to it, combined with greening up in software. The creator readily admits that this looks great at the command line, but is somewhat of a letdown when using the GUI.

Perhaps the only thing the prop build could use is some sort of user interface — the keyboard is only 3D printed and there’s no mouse or other pointing device included. There are some creative solutions to this problem, which we often see in other Fallout projects, like the ever popular Pip-Boy replica builds.

[Thanks to Sjoerd for the tip!]

Doing It With Fewer Bytes Than Bill Gates

March 24, 2017 by 29 Comments

The MITS Altair 8800 occupies a unique place in computing history as the first commercially succesful microcomputer for personal rather than business use. It is famous as the platform upon which the first Microsoft product ran, their first BASIC interpreter.

[Josh Bensadon] has an Altair 8800, and became intrigued by its bootloader. The simplest method of programming the machine is through binary using a set of switches on the front panel, and he remarks that there should be a warning in the manual: “fingers will get sore after repeated use of the small switches on the ALTAIR”.

In the Altair manual there are two listings, one 21 byte, and another in 20 bytes. Bill Gates is on record as saying that their first effort was 46 bytes long, but with more work he managed to create one in 17 bytes. Now [Josh] has beaten that, he’s created an Altair 8800 bootloader in only 14 bytes.

His write-up goes into great detail about how those bytes are shaved off, and provides us with a fascinating insight into the 8800’s architecture. Even if your 8-bit assembler is a little rusty, it’s a fascinating read.

We’ve featured Altair-inspired projects many times here at Hackaday, but rarely the real thing. This Altair PC case with the ability to emulate the original was rather a nice idea, as was this Altair front panel project. If you want the joy without the heartache though, there is an online emulator.

Ten Minute TensorFlow Speech Recognition

March 24, 2017 by 17 Comments

Like a lot of people, we’ve been pretty interested in TensorFlow, the Google neural network software. If you want to experiment with using it for speech recognition, you’ll want to check out [Silicon Valley Data Science’s] GitHub repository which promises you a fast setup for a speech recognition demo. It even covers which items you need to install if you are using a CUDA GPU to accelerate processing or if you aren’t.

Another interesting thing is the use of TensorBoard to visualize the resulting neural network. This tool offers up a page in your browser that lets you visualize what’s really going on inside the neural network. There’s also speech data in the repository, so it is practically a one-stop shop for getting started. If you haven’t seen TensorBoard in action, you might enjoy the video from Google, below.

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Half-Baked Idea: Put Your PLA In The Oven

March 24, 2017 by 22 Comments

[Thomas] wanted to try baking some carbon fiber 3D printing filament because the vendor had promised higher strength and rigidity after the parts were annealed in the oven. Being of a scientific mindset, he did some controls and found that annealing parts printed with the carbon fiber-bearing filament didn’t benefit much from the treatment. However, parts printed with standard PLA became quite a bit stronger and more rigid.

The downside? The parts (regardless of material) tend to shrink a bit in the X and Y axis. They also tend to expand in the Z direction. However, the dimension changes were not that much. The test parts shrunk by about 5% and grew by 2%. He didn’t mention if this was repeatable, which is a shame because if it is repeatable, it isn’t a big deal to adjust part dimensions before printing. Of course, if it isn’t repeatable, it will be difficult to get a particular finished size after the annealing process.

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