This is a portfolio site for Gareth Halfacree, the former systems administrator to the left – or above, on a mobile device – currently earning a living as a full-time technology journalist and technical author. You may know him from his best-selling books the Raspberry Pi User Guide and the Official BBC micro:bit User Guide, or his contributions to national magazines, radio programmes, and publications including Imagine Publishing’s Genius Guide and Tips, Tricks, Apps & Hacks series – or even his eponymous “Gareth Halfacree’s Hobby Tech” feature, a five-page spread in Dennis Publishing’s Custom PC Magazine each month. Read more
Hobby Tech this month takes a look at a trio of very different products: the Clockwork GameShell modular hand-held console, the Dexter GiggleBot BBC micro:bit-powered robot, and the Coinkite Coldcard hardware cryptocurrency wallet.
First, the Coldcard. Designed by the company behind the Opendime (reviewed in Issue 175, and dead due to an apparent design flaw a week later), the Coldcard is roughly the size of a small stack of credit cards but provides a full hardware wallet for the Bitcoin and Litecoin cryptocurrencies. At least, that’s the theory: sadly, in practice, the device proved difficult to use owing to software glitches, hardware flaws, and a lack of third-party software support which reduces you to using only one wallet package to interface with the Coldcard.
The GiggleBot, by contrast, is a significantly more polished product. While the documentation still needs work, the robot itself – featured two individually-addressable motors, a line- or light-following sensor board, RGB LEDs, and expansion potential from Grove-compatible connectors and a pair of servo headers – is exceptionally impressive, and a great introduction to basic robotics for younger programmers. Those looking to make the leap from the block-based MakeCode environment to Python, though, will discover that the two libraries are far from equivalent in terms of feature availability – something that, again, will hopefully be addressed in the future.
Finally, the Clockwork GameShell. Produced following a successful crowdfunding campaign, the device is based around a Raspberry Pi-like single-board computer dubbed the Clockwork Pi and runs a customised Linux distribution with neat menu system. Its internals, interestingly, are modular, with each contained inside a snap-together transparent plastic housing – a decision which makes for a slightly bulky Game Boy-like outer shell and, sadly, is the direct cause of some overheating problems for the system-on-chip (SoC) during more intensive games like Quake. These issues, though, are largely outweighed by sheer novelty value: a few minutes of FreeDoom in the palm of your hand is sure to raise a smile.
The full reviews can be read in Custom PC Issue 184, available from your nearest supermarket, newsagent, or digitally via Zinio and similar services.
In Hobby Tech this month, there’s a look at a project which has genuinely transformed my mornings, a tiny temperature-controlled soldering iron with a hackable firmware, and the latest brain-melting program-’em-up from Zachtronics.
Starting with the game first, Exapunks caught my eye as soon as I saw it announced by developer Zachtronics. Taking the assembler programming concept of earlier titles TIS-100 and Shenzhen-IO, Exapunks wraps them up in a 90s near-future cyberpunk aesthetic alongside a plot driven by a disease called “the phage” which turns victims into non-functional computers. Because of course it does.
Anyone familiar with Zachtronics’ work will know what to expect, but Exapunks really dials things up. From the puzzles themselves – including one inspired by an early scene in the classic film Hackers – to, in a first for the format, the introduction of real though asynchronous multiplayer on top of the standard leaderboard metrics, Exapunks excels from start to oh-so-tricky finish.
The MiniWare TS100 soldering iron, meanwhile, sounds like it could be straight from Exapunks – or, given its name, TS-100: a compact temperature-controlled soldering iron with built-in screen and an open-source firmware you can hack to control everything from default operating temperature to how long before it enters power-saving “sleep mode.” While far from a perfect design – and since supplanted by the TS80, not yet available from UK stockists – the TS100 is an interesting piece of kit, with its biggest flaw being the need to use a grounding strap to avoid a potentially component-destroying floating voltage at the iron’s tip.
Finally, the project: an effort, using only off-the-shelf software tied together in a Bash shell script, to print out a schedule of the days’ tasks on my Dymo LabelWriter thermal printer. Using the code detailed in the magazine, the project pulls together everything from weather forecasts to my ongoing tasks and Google Calendar weekly schedule – along with a word of the day and, just because, a fortune cookie read out by an ASCII-art cow.
All this, and a variety of other topics, is available in the latest Custom PC Magazine on newsagent and supermarket shelves or electronically via Zinio and similar services.
In my Hobby Tech column this month, I take a look at the disappointing Planet Computers Gemini PDA, the significantly less disappointing Proto-Pic Program-o-Tron, and the recent updates designed to make the Raspbian operating system for the Raspberry Pi significantly more welcoming to newcomers.
First, the Gemini PDA. I’ve long been a fan of the clamshell personal digital assistant (PDA) form factor, and it was with a heavy heart that I finally hung up my Psion Series 5 after it became clear that smartphones had won that particular war. Now, the format is back courtesy of Planet Computers and the crowdfunded Gemini PDA – a design based on the Psion Series 5 and put together by one of the staff responsible for the original, but which misses its mark at almost every turn.
At its heart, the Gemini PDA is an Android smartphone – even the non-4G version, which is simply an Android smartphone with the cellular radio removed. While it’s possible to run a Debian-based Linux on top, the experience is poor – but, that said, no more poor than the buggy Android build supplied with the device, which insists on booting up in German despite being clearly marked as a UK model. The hardware, too, disappoints: performance under Linux is not where it should be, and while the keyboard is a near-perfect match to the original Psion design the clever sliding hinge mechanism is entirely missing in favour of a loose and flimsy metal kickstand that fails to provide nearly enough support.
Many thanks must go to the National Museum of Computing (TNMOC), which kindly provided an original Psion Series 5MX PDA for direct head-to-head comparison during the review.
The Program-o-Tron, after a disappointing start to the month, proved considerably better. Again crowdfunded, the Proto-Pic device is designed to make life easier for those working with Atmel ATmega microcontrollers. Rather than having to program each chip individually from a PC, the Program-o-Tron allows you to hold six hex files on an SD card and flash them onto a chip inserted in the ZIF socket at the push of a button – and, even better, to take a dump of the contents of a chip, including its fuse settings, to clone it without ever needing to touch the original program code.
Finally, the recent update to Raspbian operating system for the Raspberry Pi brought a couple of changes for the better: a lightening of the load when it comes to pre-installed software, complete with a tool to add packages back in on-demand, and a first-run welcome wizard which walks newcomers through configuring the Wi-Fi networking, localisation settings, and choosing a new password. The latter is particularly welcome: since launch, the default for Raspbian has been to keep the ‘pi’ and ‘raspberry’ username and password combination, making it easy for attackers to gain access to systems accidentally or deliberately connected to public networks. By asking users to choose a new password on first boot, the hole is closed.
To read more, pick up Custom PC Issue 182 from your nearest newsagent, supermarket, or digitally via Zinio or similar distribution platforms.
Readers over a certain age will remember the glorious, though brief, age of the personal digital assistant: pocket-size gadgets, typically though not always in clamshell format, exemplified by Psion’s classic Series 5MX. The rise of the smartphone was the death of the PDA, but there’s a company still clinging to the dream: Planet Computers, with its Gemini PDA.
Reviewed in the latest HackSpace Magazine in Gemini 4G form, which adds an LTE radio for data and voice traffic allowing the device to double as a cumbersome smartphone, the Gemini traces its lineage all the way back to the Psion Series 5. Sadly, as a loaner Series 5MX kindly provided by The National Museum of Computing (TNMOC) proved, the resemblance is only skin-deep: the clever sliding keyboard mechanism of Psion’s design is replaced in the Gemini by a straightforward fold supported by a too-weak metal hinge at the back which only loosens over time.
Given HackSpace’s target audience, my review focused less on the device as supplied – running Android 7 – and more on how it acts when given a customised version of Debian Linux supplied for the more technical user by Planet Computers. Installation wasn’t straightforward, sadly, and use even less so – and a battery life test revealed the unoptimised nature of the Debian port, cutting nearly four hours off the device’s lifespan during a video playback test.
I’m still a believer that there’s a demand out there, albeit small, for what would be a true Psion Series 5MX successor: robust, chunky yet pocket-size, with an outdoor-readable display based perhaps based on colour E-Ink technology. Sadly, the Gemini isn’t it.
The full review is available now, both in print and as a free-as-in-speech-and-beer digital download from the official website.
In this month’s Hobby Tech column I take a look at two LED-adorned educational electronics kits, the Kitronik :GAME ZIP 64 and the Kano Pixel Kit, along with Mark Hardisty’s latest retrogaming project, The Classic Adventurer.
Kitronik’s :GAME ZIP 64, which will henceforth be known as the much easier to both read and type Game Zip 64, is a clever little add-on for the BBC micro:bit educational platform. Designed to mate with the BBC micro:bit’s edge connector, the Game Zip 64 adds 64 individually-addressable RGB LEDs, a major upgrade on the single-colour 25-LED matrix on the BBC micro:bit itself, buttons to form a four-way directional control pad, two fire buttons, a piezoelectric buzzer, and – interestingly – a vibration motor.
While the sample Python programs – Snake and Pong – are pretty poor, Kitronik has produced a series of lesson plans around the device which are absolutely fantastic, and put the £40 asking price well into ‘bargain’ territory for anyone looking to move on from the built-in features of the bare BBC micro:bit itself.
The Kano Pixel Kit is, on the face of it, a similar device: a matrix of 128 LEDs – twice the number of the Game Zip 64 – dominate the front, but control is limited to a function dial and a couple of buttons. It’s also Kano’s first truly standalone product, eschewing the normal Raspberry Pi for an on-board Espressif ESP-WROOM-32 microcontroller. As with the Kano Computer Kit, the Pixel Kit’s software – which, sadly, is not available for mainstream Linux, despite coming in a Raspberry Pi variant – is fantastic, but its development cost is likely behind the eyebrow-raising £75 asking price.
Finally, Mark Hardisty’s latest project – after putting his groundbreaking tome on the history of Gremlin Graphics to bed and recreating some classic artwork in Inlay – is The Classic Adventurer, a magazine dedicated to the glory days of interactive fiction. Available in print and also, all credit to him, as a free-as-in-beer DRM-unencumbered PDF download, each issue is packed with brilliant art and fascinating articles ranging from interviews to reviews with some behind-the-scenes stuff thrown in for good measure. It’s a fantastic project, and definitely one to follow.
All this, plus the usual raft of other people’s work, can be found at your nearest newsagent, supermarket, or electronically via Zinio and similar digital distribution platforms.
This month’s Custom PC Magazine sees my Hobby Tech column take a look at TheC64 Mini, a rather annoyingly-stylised recreation of the classic Commodore 64, experiment with Raspberry Pi-powered cluster computing via GNU Parallel, and drink a toast to the memory of the late and lamented Rick Dickinson.
First, Rick. Best known for having been Sinclair Radionics’ – later Research, still later Computers – in-house industrial designer, Rick is the man responsible for the iconic look of the ZX80, ZX81, Sinclair Spectrum, and Sinclair QL, among other devices. While blame for their keyboards lies further up the chain, Rick did the best with his instructions to the point where his designs are still immediately recognisable today. Sadly, Rick had been in ill health of late, and recently passed; my article in this month’s magazine serves as a ode to his memory.
TheC64 Mini, then, feels like a bit of an insult, being as it is the modern incarnation of a device from US Sinclair rival Commodore. Created by Retro Games Limited – not to be confused with Retro Computers Limited, creators of the two-years-late-and-counting ZX Vega+ handheld console, but rather a separate company formed by a split between RCL’s directors present and former – TheC64 Mini appears, at first glance, to be a breadbin-style Commodore 64 that’s been shrunk in the wash.
While deserving plaudits for actually existing, unlike the ZX Vega+, TheC64 Mini isn’t exactly a stellar success: inside its casing, which is dominated by a completely fake keyboard, is a tiny Arm-based single-board computer running Linux and a hacked-around version of the Vice emulator. Its emulation suffers from input lag, something RGL originally attempted to blame on people’s TVs before releasing an update which reduced the problem without completely fixing it, and the bundled Competition Pro-style joystick compounds the problem by being absolutely awful to use courtesy of a rubber membrane design that should have been left on the drawing board.
Finally, the cluster computing tutorial walks the reader through creating a multi-node cluster – of Raspberry Pis, in this instance, though the tutorial is equally applicable to anything that’ll run SSH and GNU Parallel – and pushing otherwise-serial workloads to it in order to vastly accelerate their performance. In the sample workload, which passes multiple images through Google’s Guetzli processor, run-time went from 1,755 seconds in single-threaded serial mode to 125 seconds running on the eight-node cluster – housed in a Ground Electronics Circumference C25 chassis, because if you’re going to do something you should do it in style.
All this, and the usual selection of other interesting articles, can be found in your nearest newsagent, supermarket, or electronically via Zinio and similar digital distribution platforms.
This month’s Hobby Tech column takes a look at an open-source microcontroller-driven hobbyist oscilloscope and a book which aims to document art in video games, while also walking readers through the rather handy trick of setting up a reverse SSH tunnel.
First, the tutorial. Since Code42 announced that CrashPlan Home, my chosen off-site backup solution, was being discontinued, I’ve been looking into alternatives. A Raspberry Pi with a USB hard drive and a copy of Syncthing installed does the job nicely, except for the issue of management: once it’s off-site, I’d have to configure someone else’s router to forward a port so I can SSH into it. An easier alternative: a reverse SSH tunnel.
Where a traditional SSH connection goes from local device to remote host, a reverse tunnel goes from remote device to an intermediary device – in my case, a home server on my own network. Your local device then also connects to said intermediary device, and you have full access to the remote device regardless of whether or not it’s behind one or more firewalls or even whether you know its public-facing IP address.
The first of the reviews, meanwhile, is a little cheeky: while the device on test is based on the JYE Tech DSO138 open-source oscilloscope design and firmware, I’ve been using a clone rather than an original – having spotted it on offer during an Amazon sale and been unable to resist a bargain. While the conclusions I draw on the scope’s functionality and usability apply equally to both, a first-party JYE Tech version is likely to feature better build quality and certainly includes better support.
Finally, my review of the coffee table tome – yes, another one – Push Start: The Art of Video Games is one of those rare occasions where I’ve been disappointed by what should have been a product aiming for a very low bar. While the full-colour hardback publication includes plenty of high-quality pictures, it also includes some extremely low-quality screenshots as well – particularly noticeable at the beginning where vector games are captured as bitmaps using MAME’s default ultra-low resolution, and at the end where tell-tale artefacts show the use of third-party JPEG images rather than first-party captures. Worse still is the limited accompanying text, which is riddled with errors.
The latest Hobby Tech is available now from newsagents, supermarkets, and electronically via Zinio and similar digital distribution services.
This month’s issue of The MagPi, the official Raspberry Pi magazine, has a review which took an unexpected turn: the Andrea Electronics PureAudio Array Microphone Development Kit, or MDK.
When Andrea’s kit – which is comprised of a PureAudio-branded USB soundcard based on a common low-cost USB audio chip, a SuperBeam stereo microphone with Velcro fixing pad, and some downloadable software – arrived, it did so under a different name: the Speech Development Kit, or SDK. The brief documentation provided explained that the kit made it easy to develop your own voice-activated software, detecting a trigger phrase and running tasks accordingly.
Sadly, that turned out not to be the case. While the bundled software does indeed activate on a trigger phrase, that’s all it does; to actually achieve anything, you need to write your own software. Not even basic text-to-speech or speech-to-text functionality is included, and while Andrea provided at-the-time unreleased ‘vocabulary files’ for individual instructions these were extremely limited and not user expandable. Worse, the clever filtering library – the only thing that makes the kit stand out from an off-the-shelf microphone and cheap USB soundcard – does not appear to the system as a driver, and is functional only with software you write yourself and the bundled extremely simple demonstration program.
Throughout the review, Andrea Electronics remained in constant communication, and took all my criticisms of the bundle on board. The result: a rapid shift in targeting, removing consumer- and hobbyist-oriented marketing from the bundle and repositioning it as a microphone – rather than speech – development kit aimed solely at professional developers. While it’s still not something I could recommend, it is at least now properly placed in the market.
For the full review, you can pick up The MagPi Issue 69 in print now at your nearest supermarket or newsagent, or download the full issue for free under a Creative Commons licence from the official website.
This month’s Hobby Tech features two different Raspberry Pi add-ons, one designed to get the best possible audio quality out of the popular single-board computer and the other designed to get the best possible audio quality into it, along with a review of Mark Hardisty’s Inlay in tradebook paperback format.
First, the let’s-play-high-quality-audio add-on: the Allo DigiOne. Reviewed in its Player format, which bundles the DigiOne S/PDIF hardware attached on-top (HAT) board with a Raspberry Pi 3, micro-SD card, power supply, and admittedly neat acrylic case – which, unfortunately, makes it really difficult to remove said micro-SD card – the DigiOne is designed to output digital audio over an RCA or BNC connector. Its primary selling point: as-low-as-possible jitter, claimed to be measured at 0.6 picoseconds – though its creators seemingly accusing optical outputs, which the DigiOne lacks, of having 4 nanoseconds of ‘jitter’ when they appear to actually mean ‘delay’ is disappointing.
The Andrea PureAudio Microphone Development Kit, by contrast, is less about the sound that comes out of a Pi and more about what goes into it. A bundling of a cheap off-the-shelf USB soundcard in custom plastic packaging with a PureAudio array microphone – the self-same design Asus used to give away with selected motherboards – the Andrea Electronics bundle originally came to me as the Speech Development Kit, full of promise about how Andrea’s clever audio library would bring crystal clarity to your applications and allow you to quickly and easily build applications you could control with your voice.
Considerable back-and-forth with the company followed, and by the morning on which the column was due with my editor a decision had been made: the Speech Development Kit, which was nothing of the sort and completely failed to deliver on its promises, became the Microphone Development Kit. While still below par – the biggest failing that, unlike the Windows driver that used to be bundled with the Asus version, the clever noise-reducing beam-forming and other-sound-enhancing Linux audio library which is the primary selling point of the kit can only be used in applications you write yourself, and will do nothing for applications like Skype or Audacity – it, at least, now sets a more realistic tone for would-be buyers.
Finally, something for the eyes. The creation of Mark Hardisty, whose A Gremlin in the Works was reviewed back in Issue 168, Inlay is a book about classic game cover art primarily concentrated on the eight-bit era. Where most coffee table books of this type simply reproduce the art as it originally appeared, Hardisty took a more challenging route: the book contains painstaking vector recreations of the original art, minus distracting titles and flashes, producing a derivative work which is clearer and crisper than anything you’ve seen before. My only regret: picking up the cheaper tradebook paperback edition, which lacks the wide format of the hardback edition and thus has less of each cover available for viewing.
All this, and the usual selection of interesting tidbits written by others, is available at your nearest newsagent, supermarket, or electronically via Zinio and similar services.