From A Dead Laptop To A Portable KVM And PiTop

An essential tool of many sysadmins is a portable terminal ready to plug into an ailing rack-mounted server to administer first aid. At their simplest, they are simply a monitor and keyboard on a trolley, but more often they will be a laptop pre-loaded with tools for the purpose. Sysadmins will hang on tenaciously to now-ancient laptops for this application because they possess a hardware serial port.

[Frank Adams] has taken a different route with his emergency server crash cart, because while he’s used an old laptop he hasn’t hung onto it for its original hardware. Instead, he’s used a Teensy and an LVDS driver board to replace the motherboards of two old Dell Latitude laptops, one of which is a simple KVM device and the other of which is a laptop in its own right featuring a Raspberry Pi 3. He’s produced a video as well, which we’ve placed below the break.

There was a time when laptop display panels were seen as unhackable, but the advent of cheap driver boards has meant that conversions such as this one have become a relatively well-worn path. The job he’s done here is a particularly well-executed one though, making good use of the generous amount of space to be found in an older business-class laptop. There isn’t a battery because this application doesn’t demand one, however, with the battery compartment intact it does not seem impossible that a suitable charger/monitor board could be included along with a boost converter to provide his 12V supply.

This isn’t the first Pi laptop in a re-used commercial machine’s case we’ve seen, there was also this Sony Vaio.

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A Nurse Call System Becomes Turing Complete

George Mallory, a famous English mountaineer, once suggested that it was of no use to climb mountains. Instead, he posited, the only reason to climb a mountain is because it is there. Likewise, when you become an expert in nurse call systems like those found in hospitals, you may find that you do things with them that are of similar use. Making a Turing-complete nurse call system is something you do because you can.

[Erik] has been working on this particular call system, known as Netrix, and used Wireshark to sniff out all of its protocols. With this information he realized that it would be possible to use the system’s routing features to perform all of the tasks that any Turing complete system can do: conditional branching and memory access. He set up a virtual machine and set about implementing all of these tasks using the nurse call system’s features.

The setup for this project is impressive, and belies an extensive knowledge of this one proprietary system but also of computer science in general. It’s interesting to see how something can be formed into a working computer system from parts that otherwise might not be used that way. Even things that aren’t electronic can be used as Turing-complete computers.

Photo via Wikimedia Commons

Our Right To Repair Depends On A Minimally Viable Laptop

It’s never been harder to repair your electronics. When the keyboard in your shiny new MacBook dies, you’ll have to send it to a Genius. When the battery in your iPhone dies, you’ll have to break out the pentalobe screwdrivers. Your technology does not respect your freedom, and this is true all the way down to the source code: the Library of Congress is thankfully chipping away at the DMCA in an effort that serves the Right to Repair movement, but still problems remain.

The ability — or rather, right — to repair will inevitably mean using electronics longer, and keeping them out of the garbage. That’s less e-waste, but it’s also older, potentially slower and less powerful portable workstations. This is the question: how long should you keep your electronics running? When do you start getting into the false economy of repairing something just because you can? What is the minimally viable laptop?

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3D Printing Logic Gates

It may seem a paradox, but in the future tiny computers may dump electronics and return to their mechanical roots. At the macroscale, mechanical computers are fussy and slow, but when your area is down to a few molecules, electronics have trouble working but mechanical systems do just fine. In addition, these devices don’t use electricity directly, don’t generate electronic signatures, and may be less sensitive to things like radiation that damage electronics. A recent paper in Nature Communications discusses how to 3D print common logic gates using both macro-scale 3D printing techniques and a much smaller version with microstereolithography. You can see a video of gates in action below.

The gates use a bistable flexible mechanism. The larger gates use ABS plastic and measure about 250mm square. The smaller gate measures less than 25 mm square. They also use a special technique to make gates as small as 100 microns theoretically possible, although some of that is future work for the team.

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Computer Algebra for Electronic Design

Don’t get me wrong. Like most people, there’s nothing I enjoy more than solving a long, involved math problem by hand. But, sometimes, a few pages of algebraic scratches on paper is just a means to an end. I find this especially true during electronic design sessions, be it circuit design or PCB layout; I just need the answer, and any time spent finding it distracts me from the larger task at hand. For me, at least, this seems to happen at least once a week, and about five years ago I decided to do something about it. I had heard of computer algebra packages, of course, but they weren’t taught as part of the undergraduate engineering curriculum when I went to school. So, I set about learning one: let the computers do the math!

The package I chose is wxMaxima, a document-based front-end to the Maxima computer-algebra system. Descended from code originally written in the late 1960s, it’s a general-purpose package supporting symbolic computation for algebra and calculus. There’s solid, mature code underneath with a modern UI veneer on top. Plus, it’s FOSS.

As I’ve progressed, I’ve found that some additional functions make the Maxima environment especially convenient for circuit design. A few are simple enough that I’d typically just re-create them as needed, so I never really got organized – there were several versions of my “library” floating around on various machines. I finally got my act together, cleaned up the most-frequently used functions, and put them into a GitHub repo.

Let’s have a look at how we can use them to take the tedium out of math for some design problems.

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Travelling The Oregon Trail With An Apple II Robot

For one reason or another, we’re going with a retro-futuristic 80s aesthetic in this case, [Mike] decided to turn an Apple IIe into a robot. If you have to ask why, you’ll never know, but this project does have some interesting things going for it. There’s a voice synthesizer, a brand spankin’ new power supply, and it rolls around on the floor thanks to Apple BASIC.

Since this is a mobile robot, there needs to be a power supply in there somewhere. The Apple II had a fantastic switching power supply, but it ran off mains voltage. To make this Apple run off a 14.8 V LiPO battery, [Mike] needed to re-engineer this power supply to give +5, +12, -5, and -12 Volts. The easiest is the positive voltage, and for that, he used a big ‘ol LM1084 linear regulator for the +5 V line. This outputs a ton of heat and probably isn’t the best solution, but it is a solution that works. The +12 line was again another linear regulator, an LM7812CV. Since this is dropping 14.8 V down to 12, the efficiency isn’t that bad, and since there’s no floppy drive it’s not pulling much current anyway. The negative voltages are a MAX764 / MAX765 inverting switching regulators. This completely replaces the original power supply in the Apple II, and is a decent reference design for anyone who wants to make a luggable Apple II laptop.

To move this thing around, the motors run on their own 11.1 V LiPO, with a bunch of Pololu gear tying everything together. The BASIC code was written on an emulator, transferred over with the Floppy Emu. Movement is controlled through the output pins on the joystick port, and there’s a text to speech module that was obviously needed and ties this project together wonderfully. You can check out the video demo of the build below.

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Review: IchigoJam Single Board Computer

It won’t replace your beloved Rasbperry Pi, but it’s worth saying hello to this “Strawberry Jam”, straight out of Japan. It’s an equally delicious way to get people interested in the basics of coding.

My hackerspace friend Jim is a lucky bloke, for last year he was able to take an extended holiday through a succession of East Asian countries. We were treated to online pictures of beautiful scenery and beaches, city lights, and of course exciting tech destinations such as hardware markets and hackerspaces. On his return he tossed a package on the table in front of me and said “Jenny, you might like to take a look at that, these are big in Japan!” Inside was an electronic kit and a few pieces of documentation, with Japanese text.

A Different Way To Get Kids Coding

The contents of the IchigoJam kit.
The contents of the IchigoJam kit.

What he’d given me was an IchigoJam (Best translation I’ve been given is “Strawberry Jam”), a small single-board computer aimed at young people. In the style of the 8-bit machines of the 1980s, it runs a comprehensive BASIC interpreter and plugs into a TV set, though it brings itself up-to-date with a USB-A socket for a keyboard. At its heart is an NXP LPC1114F102 ARM Cortex-M0 microcontroller with 32KB of Flash and 4KB of SRAM, and though the board Jim passed to me has a surface-mount example it’s clear that it was also designed for the now-obsolete DIP variant of the chip. If you were to think of this as an odd hybrid of a BASIC Stamp, a Raspberry Pi, and one of the smaller MBED boards, you probably wouldn’t be too far from the mark. What follows is my impression of it based on the information at hand. Sadly the IchigoJam website and forum seems only available to Japanese viewers and returns an error code from my European perspective.

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