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.
First, the vintage gaming feature. Building on a brief from editor Ben Hardwidge, I wanted to do something a little more in-depth than the usual how-to guide. The result is a seven-page feature which begins with a look at the wealth of accessories available to turn a Raspberry Pi or other single-board computing into a powerful emulation station, a two-page expert guide to the legalities of emulation in the UK, step-by-step instructions on downloading, installing, and configuring the RetroPie on a Raspberry Pi, and a look at entirely legitimate sources for read-only memory (ROM) game images.
While I’m fully equipped to handle the how-to and look-at-the-shiny-things sections of the guide myself, the legal aspect required an expert eye kindly provided by Eaton Smith LLP partner Chris Taylor. Legal counsel to a variety of game development and publishing companies, Chris kindly walked through the legalities of developing, downloading, and using emulation software and hardware under UK law – and even threw in a cheeky topical reference to Ernest Cline’s Ready Player One ahead of the release of its film adaptation. I’m also grateful to The Internet Archive’s software curator Jason Scott for taking the time to discuss the Archive’s vast trove of software and in-browser emulation functionality.
Meltdown and Spectre, meanwhile, are a lot less fun. The names given to a quartet of security vulnerabilities hard-baked in to the vast majority of processors built since the 1990s, Meltdown and Spectre are unarguably the worst things to happen to the computer industry since the death of the Commodore Amiga. My three-page look discusses the vulnerabilities, how they can be exploited to gain access to supposedly-protected information, and what companies are doing to fix the problems – and, spoiler, the conclusion there is “not nearly enough.” Since the piece was written, though, there’s one thing to note: installation of the KB4056892 patch for Windows 10 includes faulty microcode protection from Intel which can cause systems to reboot spontaneously, which is resolved through the installation of KB4078130 at the cost of disabling protections against one of the two Spectre vulnerabilities.
Finally, Hobby Tech itself opens with a look at the clever but fragile Opendime from cryptocurrency start-up Coinkite. Designed to turn Bitcoin into a digital bearer bond, an Opendime creates a private key which is stored in a secure enclave accessible only by irrevocably modifying the device by popping off a small surface-mount resistor. So long as the resistor is intact, the theory goes, nobody has access to the private key – meaning you can accept the device as payment without risk. Sadly, since my fairly glowing review was written two things have changed: the Opendime I’ve been carrying around on my keyring has unsealed itself without any visible damage to the resistor or the heatshrink which protects it, an issue Coinkite’s founder and support team have singularly failed to address, and the high transaction fees on the Bitcoin network have dropped from around £20 to around 20p meaning one of the major benefits of using a £15 USB device for in-person transactions has been lost.
The iFixit Pro Tech Toolkit, by contrast, is a significantly happier story. I’ve long been a fan of iFixit’s teardowns and the software they developed for presenting the information, so a toolkit with the iFixit seal of approval was high on my want list. Having now received one, I can confirm it’s no disappointment: from the high-quality tools, all bundled with the express intention of making it as easy as possible to dismantle modern electronics, to the smart multi-function storage case, the entire bundle is pleasingly robust.
Finally, Commodore: The Amiga Years. The follow-up to author Brian Bagnall’s Commodore: A Company on the Edge, The Amiga Years was officially cancelled years ago before being resurrected through a crowdfunding campaign. Since the closure of the campaign, however, the project was beset by delays and a last-minute editing decision that sees the final third of the story, taking Commodore to its sad demise, spun out into yet another book – a move backers criticising the decision have positioned as a blatant attempt at extracting more money. As with A Company on the Edge, though, the story told in The Amiga Years is one well worth the entry price – if suffering a little from Bagnall’s wandering editorial process, whereby topics raised as though you should already know them in Chapter 2 won’t be formally introduced until Chapter 5.
All this, and slightly less stuff by people who aren’t me, can be found at your nearest supermarket, newsagent, or digitally via Zinio and similar services.
This month’s HackSpace Magazine includes a review of an entirely unique device designed to make it possible to trade the Bitcoin cryptocurrency in-person as a physical item without any of the security risks that would normally be involved: the Coinkite Opendime.
For those unfamiliar, a primer: cryptocurrencies, including Bitcoin, work on the basis of a distributed ledger system known as the blockchain – a highly-secure database, effectively, which is shared between nodes and which cannot be faked or edited once committed. When you “have Bitcoins” in a “wallet,” what you actually have is the private key required to make transactions on the blockchain to move the coins you own from place to place.
The drawback of this approach compared to cold hard cash is that it becomes impossible to make secure off-chain transactions: you can save your keys to a flash drive, write them in an email, or even print them out and hand them to someone in person, but if you kept a copy it’s perfectly possible for you to transfer the coins to a different “wallet” out from under the recipient’s nose.
The Opendime aims to resolve this. Looking like a denuded flash drive itself, the Opendime is a smart self-contained microcomputer which performs the generation of private keys internally and locks them away – meaning it can receive Bitcoins but not spend them, until such a time as the private key is unlocked by popping a small surface-mount resistor off the board with a physical pin. In other words: if you receive an Opendime which reports it is still sealed, you are guaranteed to be the only person with access to that private key.
Sadly, since penning the relatively-positive review, I’ve encountered a major problem with the Opendime: having carried one on a keyring for a month or so, it spontaneously unsealed itself without the resistor being touched. Support from Coinkite has proven non-existent, and at £15 landed a piece with a minimum order of three units the Opendime is now an expensive but useless trinket while I find myself unable to trust the remaining two in the pack.
The review can be read in full within the magazine itself, which is available in print at all good newsagents and supermarkets and as a free digital download under the Creative Commons licence at HackSpace’s official website.
This month’s Hobby Tech column takes a look at a very special eight-byte – not a typo – microcomputer, walks through turning a spare Raspberry Pi into a Nav Coin-mining cryptocurrency machine, and looks forward to the launch of the ZX Spectrum Next with a look at a deep-dive book detailing the original Spectrum’s neat Ferranti Uncommitted Logic Array (ULA) chip.
First, the Mini C88. Designed by the multi-talented Daniel Bailey as a more affordable version of his C88, swapping the field-programmable gate array (FPGA) on which he implemented his own processor core design for an Arduino Zero and the extremely clever Dynamic Binary Translation (DBT) technique, the C88 is designed to be about as simple as a computer can get. Based on a custom instruction set, the C88 has just eight memory locations of eight bits apiece and is programmed by toggling each bit using a series of pleasingly tactile switches while monitoring the process on the 8×8 LED matrix that serves as its display.
For regular readers, this will all sound familiar: the original FPGA-based C88 and its 32-byte bigger brother the C3232 were the subject of an interview back in Issue 155. While Daniel has still not turned the C88 into a kit you can head out and buy, the Mini C88 is definite progress in that direction – and, as always, anyone interested in the project should hassle him about it on Twitter.
For those with a Raspberry Pi and a desire to play with cryptocurrency, meanwhile, this month’s tutorial will be of definite interest: a guide to turning a Pi into a ‘Stake Box’ for the Nav Coin cryptocurrency. Designed as an alternative to Bitcoin, Nav Coin offers those who run network nodes rewards in the form of a five percent return on their coin holdings when locked up in this manner. Taking less than an hour to set up and requiring nothing more than a low-powered computer, it’s a great way to get involved – and the Nav Coin project itself definitely one to follow.
Finally, while waiting impatiently for my ZX Spectrum Next microcomputer to land – which, I’m pleased to say, has since happened – I enjoyed a re-read of Chris Smith’s excellent The ZX Spectrum ULA: How to Design a Microcomputer. Based on interviews and deep-dive analysis, the book investigates the tricks and techniques which allowed Sinclair Computers to build the ZX Spectrum micro at such a bare-bones cost – which, in turn, was thanks to clever use of an Uncommitted Logic Array (ULA) chip from Scottish electronics giant Ferranti. Effectively a write-once version of the modern FPGA, Ferranti’s ULA saw the number of components in the ZX81 drop to a quarter compared to the ZX80 and is key to how the ZX Spectrum does what it does.
For all this, and a bunch of other interesting things by people who aren’t me, pick up a copy of Custom PC Issue 174 from your nearest supermarket, newsagent, or digitally via Zinio and similar services.
The workshop first: organiser Andrew Back got in touch with me shortly before the OSHCamp workshop day, held in Hebden Bridge as part of the annual Wuthering Bytes technology festival, was due to take place. The scheduled soldering workshop was at risk, he explained, as the person due to run it was no longer available. I was happy to help, and I’m pleased to report a great day was had by all assembling Cuttlefish microcontroller kits – despite the use of some particularly ancient soldering irons with tips which appeared to be made of freshly-hewn coal!
The Haynes Retro Arcade Kit feels like a device which could have been in the DIY console shootout, but it wouldn’t have fared well. Designed by Eight Innovation and slapped with the Haynes brand, the Retro Arcade Kit is a fiddly and distinctly unrewarding soldering kit which ends up as a particularly basic version of Pong. The coin activation system is its only redeeming feature: two pieces of thick solid-core wire sit side by side, and are shorted out by an inserted metal coin to start a fresh game. Not an original trick, but one well implemented – if you ignore the terrible instructions and poor build quality.
Syncthing, meanwhile, has been a mainstay of my toolbox for years. An open-source project designed to keep files on two or more computer systems synchronised, Syncthing is built with security and convenience in mind – and works a treat on the Raspberry Pi. Given that I was needing to find a new home for my off-site backups anyway, as my regular provider CrashPlan is ceasing its cheapest product line, it seemed natural to write up the process of turning a Pi and a USB hard drive into an off-site backup destination.
Starting with the latter, A Gremlin in the Works is another fantastic coffee-table book from retro computing publisher Bitmap Books (the founder of which, Sam Dyer, I interviewed back in Custom PC Issue 136). Written by Mark Hardisty based on exhaustive interviews – and retaining the question-and-answer style of the transcripts, making for an accurate rendition of the subjects’ thoughts but a slightly tiresome read – the two-volume book chronicles the rise and fall of gaming pioneer Gremlin Graphics. As a massive fan of Gremlin’s output – to this day the intro music to Hero Quest brings joy to my heart, and I blame my sweet tooth on a Zool addiction – A Gremlin in the Works is a book I’d long been looking forward to reading, and I’m pleased to say it didn’t disappoint.
Blog in a Box, meanwhile, is an interesting beast. At its heart, it’s a single-purpose GNU/Linux distribution for the Raspberry Pi created by Automattic as a means of making it easier for people to run the WordPress blogging platform from the device. It’s not provided as a downloadable drive image, as with most distributions, though; instead, Automattic has written a cross-platform program which customises various settings – title, passwords, email accounts, things like that – and configures them so the Pi is ready to rock on first boot. It’s a neat idea, but one which still needs polish: I found the Linux version failed to run properly on my Ubuntu 16.04 desktop, and several features promised by the tool were disabled when the Pi actually started up. It’s a tool with promise, though, and I look forward to revisiting it should Automattic release an update.
Finally, the Mooltipass Mini. The brainchild of Mathieu Stephan, the Mooltipass Mini builds on its non-Mini predecessor to create a pocket-sized hardware password safe for all your accounts – or, at least, as many as will fit in 8Mb (1MB) of internal memory. The Mooltipass Mini is a tool for the adequately paranoid: passwords, though not usernames, are stored in the device’s internal memory under AES-256 encryption with the private key located on a removable smart card itself locked with a four-hexadecimal-character PIN. When a password is required, its entry can be found on the screen and the Mooltipass does its best impression of a USB keyboard by typing the account details in on your behalf – or, when the optional software is installed, filling in forms in browser windows automatically upon manual confirmation on the device itself.
Having long advocated for the use of password managers to promote high-quality password use and discourage password reuse, the Mooltipass Mini is a near-perfect companion. It addresses the majority of the problems with traditional password managers, like how to keep the encrypted database accessible while preventing its theft. While there are undeniable issues, such as the £61 (inc. VAT) retail price and the need to buy two so you have a backup to use if the primary one fails, it has become a part of my security arsenal – and one I feel comfortable using thanks to the project’s open-source nature for both the software and underlying hardware.
All this, and a whole mess of other things written by people who aren’t me, is available in the latest Custom PC Magazine from your nearest supermarket, newsagent, or electronically via Zinio and similar digital distribution services.
This month’s Custom PC features a look at the effect of compiler optimisation on applications plus reviews of Google’s AIY Voice Kit for the Raspberry Pi family and Jimmy Wilhelmsson’s Generation 64.
The tutorial, to begin, stemmed from investigations I was carrying out into Google’s Guetzli perceptual JPEG encoder. Having cut my teeth in computing back when every byte – never mind kilobyte – really counted, I have a soft-spot for compression both lossy and lossless. Over the years I’ve toyed with a range of compression algorithms, from LZMA and Robert Jung’s ARJ through to the clever if short-lived Fractal Image Format (FIF). Like most, though, I eventually settled on two popular formats for my image compression needs: JPEG where lossy compression is acceptable and PNG where it isn’t.
Guetzli aims to cut the file size of JPEG files by around a third for no apparent loss in perceived image quality. That was enough to pique my interest, but it comes at a cost: a runtime of minutes per megapixel to recompress each image. As an open-source project, Guetzli is provided in source-code form – so I began to play with the optimisation options available in the GNU Compiler Collection (GCC) to see if I couldn’t speed things up.
As readers of my column will discover, I could indeed speed things up – cutting the time taken to compress the small sample image provided with Guetzli from 14.3 seconds using Google’s precompiled binary version down to just 9.56 seconds. Although not an exhaustive guide to compiler optimisation in general nor even GCC-specific options – a topic which would take a book, rather than a couple of magazine pages, to cover adequately – hopefully the write-up of my experiments will help shine a light on the gains that can be made, the potential pitfalls of excessive optimisation, and the benefits of open-source distribution.
The Google AIY Voice Kit, meanwhile, is something quite special: an add-on for the Raspberry Pi family of microcomputers which, in essence, turns them into a somewhat cut-down version of the company’s Google Home voice-activated assistant platform. Initially distributed with The MagPi Magazine as a cover-mounted giveaway, the kit should soon be available for purchase by the general public – and it’s definitely worth seeking one out.
The kit itself centres around a Hardware Attached on Top (HAT) add-on board, which includes servo and motor control, connectivity for an arcade-style button, and links to a break-out board with a pair of MEMS microphones. Combined with some simple software and a link to Google’s cloud computing platform, the AIY Kit can be made to respond to your natural-language queries or even control external hardware via voice recognition – with some major caveats regarding how often you can use it before you need to start handing over cash for the voice recognition platform.
Finally, Generation 64. Originally written in Swedish by Jimmy Wilhelmsson and with design by Kenneth Grönwall, Generation 64 investigates the influence the Commodore 64 had on the Swedish computing scene – complete with an introduction by the founder of Digital Illusions, also known as DICE, and MOS 6502 creator Chuck Peddle. Translated into English and re-released by Bitmap Books, Generation 64 is an absolutely fantastic read which I would have otherwise missed had it remained untranslated.
Full details on all of these, plus a bunch more stuff written by people who aren’t me, can be found in Custom PC Issue 167 at your nearest supermarket, newsagent, or digitally via Zinio and rival distribution platforms.
Readers of my regular Hobby Tech column this month will find a BBC micro:bit-driven tutorial alongside two reviews covering the remarkable Raspberry Pi Zero W microcomputer and the fascinating Delete by Paul Atkinson.
The idea for the tutorial came about while working on a chapter of my upcoming Micro:bit User Guide, and seemed like a perfect fit for the readers of Custom PC Magazine: turning the low-cost yet extremely flexible micro:bit into an addressable USB-connected 5×5 LED matrix and having it display current CPU load in a constantly-updating bar graph. Naturally, the same technique could be used to graph almost anything.
The secret lies in MicroPython’s REPL, an interactive interpreter which can run on the micro:bit and accept commands via the USB serial port. By switching the micro:bit into REPL mode, it can be slaved to another system over USB. The result: the entire program code, written in Python using the serial, time, and psutil libraries, exists purely on the host machine. A quick bit of Blu-tack later, and my monitor was wearing a CPU monitor which worked even when the display was off.
The Pi Zero W, meanwhile, was a device to which I had been looking forward for quite some time. An upgraded version of the original £5 Raspberry Pi Zero microcomputer, the Pi Zero W differs in only one respect: it has a built-in radio module, the same BCM43438 as found on the far larger and more expensive Raspberry Pi 3.
While the addition of the radio module, which offers Bluetooth, Bluetooth Low Energy, and 2.4GHz Wi-FI connectivity, almost doubles the price of the Pi Zero W to £9.60, it’s money well spent. In almost every Pi Zero project I have built, I’ve ended up using a USB OTG adaptor and low-cost USB Wi-Fi dongle to add network connectivity, and having it on-board – even at a slightly higher cost compared to a USB-connected solution – makes life considerably easier.
Finally, Delete. Billed as “a design history of computer vapourware,” Paul Atkinson’s coffee table book is packed with high-quality photographs – and, for the rarer machines, the occasional rescaled JPEG exhibiting unfortunate compression artefacts – covering machines from an upgraded Sinclair QL to a bright yellow IBM that never left the drawing board. Each comes with pages on its history, with interview subjects detailing features and failures alike, and while not all machines were strictly vapourware few are likely to have a place in the average vintage computing collection. In short: if you like old computers you’ll like Delete, which is available now from Amazon and other bookstores under ISBN 978-0857853479.
As always, you can read the whole column and a whole lot more by picking up Custom PC Issue 166 from your nearest supermarket, newsagent, or electronically via Zinio and similar services.
First, the RTk.GPIO. The brainchild of Ryan Walmsley, interviewed back in Issue 129, the RTk.GPIO is designed to bring all the joy of the Raspberry Pi’s general-purpose input-output (GPIO) header to any PC with a free USB port. A surprisingly sizeable red-hued circuit board, the RTk.GPIO includes a Pi-compatible 40-pin GPIO header with pin-out on the silkscreen. A quick pip install of the Python library later, and you can pretty much take any RPi.GPIO program and have it run natively on your Windows, Linux, or macOS machine.
Perhaps the biggest power of the RTk.GPIO is in assisting with the development of software for Pi add-ons, using the extra computing power of a desktop or laptop to make your life easier then allowing you to transfer your program to a real Raspberry Pi with minimal changes once complete. Its only real downside, in fact, is price: it’s more expensive than picking up a Raspberry Pi Zero and turning it into a USB device, though undeniably smoother to use.
The Kitronik kit, meanwhile, is one of a range of add-ons I’ve been playing with for my upcoming Micro:bit User’s Guide. Based around a GPIO expansion board for the micro:bit’s edge connector, the kit comes with mounting plate, solderless breadboard, jumper wires, and all the components you need to work through the included full-colour tutorial book – plus, in the version I picked up, the micro:bit itself, though the kit is also available without for those who already have the BBC’s miniature marvel.
In the years I’ve been playing with hobbyist electronics, I’ve seen these kits go from the most hastily thrown together things to extremely polished collections of hardware – and Kitronik’s kit definitely sits at the right end of that spectrum. There are nits to be picked, such as the lack of a handy plastic parts box for storage and no use of the lovely breadboard overlay sheets that make the Arduino-centric ARDX kit so easy to use, but it’s hard to imagine someone buying the Kitronik kit and being disappointed.
Finally, the GPIO Hammer Header. I’ve long been a fan of Pimoroni’s products, but the Hammer Header is by far both the simplest and the smartest I’ve seen. Designed for anyone who has purchased a Raspberry Pi Zero and wants to make use of the unpopulated GPIO header but who doesn’t fancy firing up a soldering iron, the kit makes use of cleverly-shaped pins which can make a suitable electrical connection purely mechanically.
The kit gets its name from the acrylic jig used for installation: assemble the jig with the Pi Zero in the middle, then give it a few sharp raps with a hammer to push the pins home. Male and female variants are available, allowing you to quickly install headers on both the Pi Zero and compact pHAT add-on boards, and to my surprise both installed quickly, easily, and without a single poor joint – and in a fraction of the time of soldering all 40 pins by hand.
For all this, and more, pick up the latest Custom PC Magazine from your nearest supermarket, newsagent, or digitally via Zinio or similar services.
In this month’s PC Pro Magazine I take a look at possibly the least original product to have ever come out of Asus’ labs: the Raspberry Pi clone known as the Tinker Board.
Designed to help Asus capture a slice of the lucrative maker market, the Tinker Board is a one-for-one feature-and-footprint clone of the Raspberry Pi 3: it’s a roughly credit-card-sized single-board computer with an ARM processor, wired Ethernet, Wi-Fi and Bluetooth radios, four USB 2.0 ports, an HDMI port, analogue audio, Camera Serial Interface (CSI) and Display Serial Interface (DSI) ports, and a 40-pin general-purpose input-output (GPIO) header. So far, so cloned.
Where Asus has tried to improve upon its inspiration is in the raw specifications: the processor, while 32-bit to the Raspberry Pi 3’s 64-bit, is considerably faster; there’s double the memory, a supposedly gigabit network connection which isn’t bottlenecked by a single-channel USB bus, support for 4K video playback, and high-resolution 24-bit 192KHz audio. If all of that were true, it’d be easy to overlook the higher selling price of the Tinker Board compared to the Pi on which it is based.
Sadly, my review didn’t go smoothly. The Tinker Board has hit the market in a parlous state. The 4K video playback is choppy, the GPIO port barely works and none of its features beyond simply toggling a pin on and off are available, hardware accelerated video playback is barely functional, and the ‘gigabit’ Ethernet port no faster than the 10/100Mb port on any standard Raspberry Pi.
To be fair to Asus, the majority of the problems I encountered – bar, possibly, the Ethernet performance – were likely related to the software provided, which appears to be in a very early alpha stage. It’s a device I’ll be keeping to one side in the hope of revisiting it in the future, should Asus ship improved software.
For a full run-down of my experience with the board, pick up the latest PC Pro at your nearest supermarket, newsagent, or electronically on Zinio and other digital distribution platforms.
"Not only should it be an essential purchase with the micro:bit, I would recommend getting the book before getting the micro:bit. Definitely recommended." "This is an amazing educational tool." "For a newcomer I would recommend this book and the BBC micro:bit. Together, they will make an excellent coder/DIY enthusiast out of you or your child." "This is definitely the book to get you started." "The best book on micro:bit I've found so far." "A wealth of information on micro:bit and it's easy to read." "Just started reading your book, and it's exactly what I was looking for."
"I'm constantly reading tech manuals. This book is above and beyond ANY tech manual I have ever read! It is readable, understandable and a fine companion for the Pi." "I have been using computer manuals for 40 years and this is one of the best I have ever read." "All I was looking for is combined in this fantastic book." "I bought this book on my Kindle and it has transformed my understanding." "A brilliant book to help you out." "This book is a must have and works very well on my Kindle - thank you so much for writing it."
There's a new @TheMagP1 on shelves today, with my review of the Allo DigiOne Player S/PDIF digital transport - and, as always, you can download the issue free under the Creative Commons licence! https://t.co/mfVtVi19tQ