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
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.
The launch of a hardware refresh for the low-cost yet surprisingly-capable Raspberry Pi single-board computer is always a great opportunity to take stock of how the project has progressed since its launch six years ago, and the result is this: a special cover feature for The MagPi celebrating the release of the Raspberry Pi 3 Model B+, or Pi 3 B+ to its friends.
Following roughly the same format as my cover feature for the launch of the Raspberry Pi 3 from March 2016, and my cover feature for the Pi Zero’s launch back in November 2015, my multi-page feature begins with an overview of the board highlighting its key new features with high-resolution call-out photography: the new Broadcom BCM2837B0 system-on-chip which dispenses with the old plastic package for a new direct-die layout protected by a metal heatspreader; the new dual-band 2.4GHz and 5GHz Wi-Fi and Bluetooth radio module; a Pi Zero-inspired ground plane antenna, which boosts wireless performance still further; a Power over Ethernet (PoE) header for the optional PoE HAT; gigabit Network connectivity; and a custom-designed power management integrated circuit (PMIC) which improves regulation and assists with the clockspeed increase to 1.4GHz.
Taking a brief pause for a quick getting-started guide for those new to the Raspberry Pi, the feature then gets into its stride with a full suite of benchmarks across two pages. Measuring everything from CPU and memory performance to Ethernet throughput, power draw, and Wi-Fi signal quality, the benchmarks don’t just cover the Pi 3 B+ and its immediate predecessor; the benchmarks compare the new board to every single mainstream model of Raspberry Pi in the project’s history, all the way back to the original Model B from the initial pre-production run. If you’ve ever wondered how things have improved over time, this feature will let you know exactly that.
A further two pages are taken up by my interview with Raspberry Pi Foundation co-founder Eben Upton, who first introduced me to the project all those years ago. Diving into the changes and improvements made in the Pi 3 B+’s design, which is the work of engineer Roger Thornton, the interview also includes several behind-the-scenes images and – because I can never resist the opportunity – a thermal imaging analysis demonstrating how the new packaging and thicker PCB help the Pi 3 B+ deal with heat dissipation, despite its faster clock speed compared to the hot-running Pi 3.
To read through the full feature, which also includes a more detailed getting-started guide and ten project ideas which take advantage of the board’s increased power, head to your local newsagent, supermarket, or download the issue digitally under the permissive Creative Commons licence from the official website.
My contribution to the latest issue of HackSpace Magazine is a detailed look at the ZX Spectrum Next, an open-hardware reimplementation of the Sinclair ZX Spectrum microcomputer with a wealth of improvements and enhancements.
Officially licensed from the current owner of the Spectrum rights – Sky In-Home Services, oddly enough, which requires only that a portion of any proceeds are donated to charity – the ZX Spectrum Next builds on the original with a Z80 implementation on a field-programmable gate array (FPGA) which can be run in accelerated mode at up to 14MHz, up to 2MB of memory, SD card storage, built-in joystick ports, crystal-clear HDMI video output, four-channel AY sound, support for original Spectrum keyboards or modern PS/2 keyboards, and even optional real-time clock, ESP8266 Wi-Fi, and Raspberry Pi Zero-based co-processor add-ons.
Despite these upgrades – and more I haven’t mentioned, including a brand-new operating system dubbed NextOS, 256-colour display modes, and hardware sprite support – the ZX Spectrum Next also boasts full backwards compatibility with software and hardware designed for the original Spectrum family, which is something of an impressive achievement given the relatively modest resources available to its creators following a successful crowdfunding campaign for its production.
The ZX Spectrum Next reviewed here, though, isn’t quite the finished article. Provided to backers eager to get their hands on the device as early as possible, the board-only ZX Spectrum Next Issue 2A is aimed primarily at developers. It also comes with an annoying design flaw, which was discovered post-review: a missing capacitor which can cause stability issues when coupled with low-quality power supplies. The finalised Issue 2B, its creators promise, will include the missing capacitor along with a keyboard and chassis housing designed by Sinclair’s long-term industrial designer Rick Dickinson.
For a full look at the ZX Spectrum Next, you can pick up Hackspace Magazine Issue 5 at your nearest supermarket, newsagent, or as a free download under the Creative Commons licence at the official website.
The launch of the shiny new Raspberry Pi 3 B+ offers a chance to revisit the entire history of the Pi family, benchmarking each device in turn from the original Raspberry Pi Model B launch board with its somewhat limited 256MB of RAM right through to the shiniest and newest board. This post collates the results from a range of different benchmarks, demonstrating how the power of the Pi has changed over the years.
If attempting to replicate the results yourself, there is one key fact to note: the Raspberry Pi has enjoyed somewhere in the range of a 30 percent performance uplift in the last couple of years through software and firmware optimisation alone; comparing the same benchmark run on a Pi using the latest Raspbian operating system today with results gathered a year or more ago will give a false reading, which is why all these results have been gathered using the same firmware and software revision.
First, the ZX Spectrum Next. The product of a highly successful crowdfunding campaign that drew in around three quarters of a million pounds from backers across the world, the ZX Spectrum Next is exactly what it sounds like: the next entry in the long-running Sinclair Spectrum family, long after even its most ardent fans had given up hope. Although based around ‘soft’ cores running on a central FPGA, the Next isn’t an emulator: the open design is entirely compatible with every piece of software or hardware you can throw at it, complete with accessories designed for the original Spectrum. It’ll even fit in a 16K/48K chassis, if you don’t mind drilling a few extra holes.
Those holes, you see, are needed for just some of the Next’s shiny new features: a pair of joystick ports, HDMI and VGA video outputs, and even the ability to insert a Raspberry Pi Zero into a special header for use – once the software has been written – as a co-processor, or as it was known at the time a “copper.” There’s room for up to 2MB of RAM, triple-chip FM synthesis, even Wi-Fi network support – though a design flaw discovered shortly after the review went to print means that anyone with the early-release Model 2A will need to solder a small capacitor onto the voltage regulator for full reliability, an issue fixed with Model 2B onward.
The NesPi, by contrast, is a lot simpler. At its heart, it’s a plastic case into which you can install a Raspberry Pi B+, 2, or 3. Its designers, though, have decided to create something a little different, and the Nintendo Entertainment System ‘inspired’ housing also includes daughterboards which offer four front-facing USB ports – two where the controllers would connect and another two under the ‘cartridge’ flap – along with working power and reset buttons. The Ethernet port is also brought to the front, for no readily apparent reason, while the dedicated power board includes a header for an optional cooling fan.
Finally, Britsoft is a book that has been on my shelves awaiting review for a little while now. A Read Only Memories publication, this impressive hardback tome gathers interview content originally created for the 2014 documentary From Bedrooms to Billions charting the rise of the British computer games industry. You’d be hard pushed, off the top of your head, to think of a luminary of the era not included in the title’s impressive 420 pages, and I had but one real complaint: the layout of the book is easier on the eye than the brain, often making it difficult to follow which speaker is talking and which topic you’re reading.
All this, and the usual collection of stuff by other people, is available now at your nearest newsagent, supermarket, or digitally via Zinio and similar services.
This month’s MagPi magazine includes a review of the Allo DigiOne Player, a clever though high-priced add-on for the Raspberry Pi which its creator claims gives it pitch-perfect digital audio capabilities.
Designed as a ‘digital transport’ – a device which provides a digital, rather than analogue, signal for decoding by an external digital-to-analogue converter (DAC) – the DigiOne Player is a plug-and-play design based on Allo’s DigiOne S/PDIF HAT. As the name suggests, the primary part of the Player is a Hardware Attached on Top (HAT) add-on for the Raspberry Pi which provides a Sony/Philips Digital Interface (S/PDIF) audio output on an RCA or BNC jack; the Player is simply a bundle which includes a Pi, case, and cabling.
There’s no denying that the DigiOne is a clever design, with a surprising amount of hardware crammed into a small space. At nearly £150, though, it’s priced head and shoulders above the competition and lacks some of their features – such as the optical output of the £30 JustBoom Digi HAT, ditched due to what Allo calls unacceptable built-in jitter levels avoided through the use of electrical connectivity.
For my conclusion on the device’s value, you can pick up The MagPi Issue 67 at your nearest supermarket, newsagent, or for free download under a Creative Commons licence via the official website.