What’s all this?

Question MarkWell, it’s a portfolio of Gareth Halfacree’s work, silly. He’s 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 book the Raspberry Pi User Guide, which has sold over 100,000 copies and has been translated into numerous languages, or his contributions to national magazines, radio programmes and books including Imagine Publishing’s Genius Guide and Tips, Tricks, Apps & Hacks series and his eponymous “Gareth Halfacree’s Hobby Tech” feature, a five-page spread in Dennis Publishing’s Custom PC Magazine each month. Read more

The MagPi, Issue 42

The MagPi Issue 42This month’s instalment of The MagPi, the official magazine of the Raspberry Pi Foundation, includes a short project I created upon request from editor Russell Barnes: soldering a reset switch to a Raspberry Pi Zero.

While part of a feature on projects specifically for the Zero, the reset switch mod is actually applicable to any modern Raspberry Pi. It makes use of the RUN header, which when shorted out causes the processor on the Pi to act as though the power has been briefly cut. The result: an instant hard reboot, even if you’ve found a way to crash the system hard. The header also doubles as a remote power switch: if the Pi is powered off but plugged into a live power supply, shorting the RUN header will begin the boot process.

Attaching a switch to the reset header is as simple as soldering two pins, but the audience of the magazine spans the gamut from absolute beginner to highly-qualified engineer. As a result, a very specific angle was chosen for the tutorial: introducing someone to the art of soldering, using the simple two-pin reset switch as a less daunting entry point than the significantly larger GPIO header soldering project found back in Issue 40.

As always, the tutorial includes plenty of photography taken in my home studio. For much of the work I do, I’ve found my Nikon 40mm macro lens to be indispensable; the only time it typically leaves my camera is if I’m doing portraiture or low-light photography (in which case it’s replaced by an f1.8 50mm prime lens) or if I need wide-angle or telephoto shots (15-35mm and 70-300mm lenses respectively) during event coverage.

The tutorial, plus various exciting Pi-related things written by people other than myself, can be found gracing the shelves of supermarkets and newsagents throughout the country, or can be downloaded free of charge from the official website under a Creative Commons licence.

Linux User & Developer, Issue 161

Linux User & Developer Issue 161To say this month’s Linux User & Developer is a bumper issue is something of an understatement: in addition to my usual four-page news spread, you’ll find a three-strong group test of Steam Machines and a detailed step-by-step guide to building your own Linux box from a pile of parts.

First, the group test. Editor Gavin Thomas contacted me with the news that they had an Alienware Steam Machine in, and asked whether I would be able to source and review a rival device for a head-to-head. I went one better, the overachiever that I am, and thanks to the very lovely people at CyberPower and Zotac I was able to pick up a Syber and NEN to be run through their paces alongside the Alienware.

For Linux User & Developer, the Steam Machines were very new territory. The magazine has previously focused largely on professional uses for Linux, but the launch of mainstream-targeted console-beating gaming PCs running Steam OS – Valve’s gaming-centric customisation of Debian Linux – couldn’t be ignored. I started by designing a series of benchmarks which could be run across all three machines in order to provide a performance comparison, which then needed to take into account the price difference between the two entry-level machines from Alienware and CyberPower and the top-end Zotac NEN. The winner? Well, you’ll have to read the review.

A major group test like this would normally be enough, but Gavin also asked me to come up with a cover feature for the issue: building your own Linux machine. As with the group test, this issue marks the first time Linux User & Developer has strayed into the PC-building arena, and Gavin was looking for someone who could lend an expert eye to the hardware side of the feature.

After an initial hiccough with a parts supplier that let me down, the wonderful people at Overclockers UK were kind enough to loan me a shopping cart full of hardware, including an Intel Skylake processor. The specifications of the machine were kept low enough to appeal to buyers on a budget looking for a future-proof bargain, while having enough poke to ensure a pleasant experience. Naturally, the hardware was chosen specifically with Linux compatibility in mind – though the Skylake family of processors does require the Linux 4.4 kernel or newer to run at its full potential, which is covered in the software-centric second half of the feature.

Issue 161 is definitely a personal highlight, containing as it does such a large percentage of contents from my trusty keyboard. You can see the result for yourself with a trip to your local supermarket, newsagent, or through digital distribution services such as Zinio.

Custom PC, Issue 150

Custom PC Issue 150There’s a bit of a theme to four of the five pages that make up this month’s Hobby Tech column, and with little surprise: I’ve been focusing on the Raspberry Pi Zero, that remarkable £4 microcomputer which is still proving impossible for retailers to keep in stock. That’s not to say it’s entirely Pi-themed, though: I found room for a look at the lovely CodeBug, too.

Naturally, the first thing I had to do when the Raspberry Pi Zero – a fully-functional Raspberry Pi microcomputer, equivalent in specification to the Raspberry Pi Model A+ but with twice the RAM at 512MB and a new 1GHz stock speed for the BCM2835 processor. The fact that the Raspberry Pi Foundation was able to pack all that into a device around half the footprint of the already-tiny Model A+ is impressive enough, but with a retail price of just £4 the Pi Zero is nothing short of revolutionary.

Sadly, my hope that stock issues would be cleared up by the time the issue hit shop shelves proved unfounded: while stock has appeared at the official outlets several times since the Pi Zero launched, it has immediately sold out again – making the device difficult to get hold of and leaving the market rife with sandbaggers flogging the £4 device for anything up to £50 on auction sites. My recommendation: be patient, keep an eye out the official outlets, and don’t reward the sandbaggers with your custom.

With the Pi Zero in hand, I figured a tutorial would be a logical next step. Perhaps one of the most impressive demonstrations of the new form factor’s flexibility comes in turning it into a true random number generator (TRNG) – at least, what Broadcom claims is a TRNG – for a USB-connected server or PC, improving security for a tenth the cost of the nearest off-the-shelf TRNG. While I used the simple method of attaching a USB-to-TTL serial adapter to the Pi Zero’s GPIO header, it’s even possible to create the same device with a single USB cable for data and power by replacing the stock kernel with one tweaked for USB OTG use – a cost-saving trick for another column, perhaps.

Finally, the CodeBug. I’d been planning on reviewing this for some time, but getting my hands on a sample proved tricky until oomlout was kind enough to loan me a unit from the device’s original crowd-funding campaign. Designed for educational use, and the inspiration for the BBC’s much-delayed micro:bit, the CodeBug is a microcontroller with on-board inputs and outputs and a built-in battery connector. Programmed using a modified version of the block-based Scratch language, it’s a great tool for teaching basic computer concepts – and I now have my hands on a few upgrades for the device, which will be appearing in a future issue.

All this, plus a bunch of stuff written by people who aren’t me, can be yours with a trip to any good newsagent, supermarket, or from the comfort of wherever you’re reading this via Zinio and other digital distribution services.

The MagPi, Issue 41

The MagPi Issue 41Following on from last month’s Pi Zero extravaganza, my workload for the latest issue of the Raspberry Pi Foundation’s MagPi was pretty light: a single review, looking at the wonderful Bare Conductive Touch Board Starter Kit.

I actually received and wrote this review some time ago, but various flat-plan changes led to it being bumped from its planned issue with the first suitable gap being in this New Year’s edition – published, as is so often the case with print publications, just before Christmas. Thankfully, the Touch Board isn’t really something that ages, and the model you would buy today is the same as the one I reviewed a few months back.

For those not familiar with the company’s output, Bare Conductive made a name for itself with a conductive paint suitable for making paper-based circuits. This was followed by the Touch Board, an Arduino-compatible microcontroller with built in capacitive touch and distance-tracking sensor capable of playing MP3 audio files from a micro-SD card depending on which of its inputs were triggered. The Starter Kit, then, unsurprisingly brings both inventions together: there’s a pot of the conductive paint plus a tube for more accurate dispensing, a brush, a Touch Board, crocodile clips, a rechargeable speaker, micro-SD, USB cable, and everything you need to build three example projects.

The bundled book is extremely good: printed on quality paper in full colour and with a modern layout, it goes some way to justifying the far-from-impulse near-£100 price point of the kit. So too does the out-of-box experience: MP3 files are pre-loaded on the micro-SD card, and if you connect the touch board to a USB port for power and poke each contact in turn you’ll be given voice guidance through its capabilities and use.

If you want to read more about the kit, the review is available in the free MagPi Issue 41 PDF or in print at newsagents and supermarkets throughout the UK.

Linux User & Developer, Issue 160

Linux User & Developer Issue 160In this month’s Linux User & Developer, following my regular four-page news spread, you’ll find a review of a device that’s a little out of the ordinary: the NeuG, a true random number generator (TRNG) which costs a remarkably small amount.

When you’re using cryptography, you’re chewing up your system’s supply of randomness – or entropy. Linux, in common with other operating systems, works to fill its entropy pool by sampling a variety of things: traffic coming in on the network port, where you’re pointing the mouse and how fast it’s moving, and even how long it takes you to press particular keys. That’s all well and good for a desktop, but for a headless server it can take a while to fill a depleted entropy pool.

Coupled with the fact that it’s very difficult for a computer to produce truly random output, there’s a market for true random number generators. These devices typically cost a small fortune but use a variety of techniques – ranging from physically breaking down pieces of hardware with high voltages and measuring the resulting changes to pointing a webcam at a lava lamp – to generate a constant stream of high-quality entropy.

Enter the NeuG, which was kindly supplied for test by the Free Software Foundation. While it looks like a flash drive that has lost it’s casing, the device is actually a miniature computer in its own right. Using on-board analogue sensors, the NeuG can generate what is claimed to be a stream of true random numbers – numbers which are then pushed through a conditioning hash and spat out of a virtual serial port. Simply link the NeuG to something like the rngd entropy gathering daemon, and kiss goodbye to entropy exhaustion in even headless or virtualised environments.

I have been extremely impressed with the NeuG, especially given its low $50 cost. While there are cheaper alternatives – such as using a $5 Pi Zero and USB TTL serial adapter to create something similar using the BCM2835’s on-board hardware random number generator module – the NeuG’s free nature, whereby the design and source code are all available for review and modification, make it a great choice where certified security isn’t a requirement.

For the full run-down, including benchmarks, you can pick up the latest issue of Linux User & Developer from your nearest newsagent, supermarket, or electronically via Zinio and similar digital distribution platforms.

Custom PC, Issue 149

Custom PC Issue 149This month’s Hobby Tech has just two component parts: a long-term review of the Tenma 60W Digital Soldering Station, and a in-depth guide to building an ultrasonic distance sensor using a Spark Core for a somewhat novel application: shaming me into using my standing desk more.

Looking at the tutorial first, it all stemmed from an office move in which I bought a vast quantity of Ikea furniture. Among it all was a new desk, which for a small extra fee I was able to get with a simple hand-crank mechanism fitted to adjust its height. As I spend the vast majority of my life in front of a computer, I thought a little change like spending some of the day standing instead of sitting would do me the world of good – but, as could be expected, after an initial burst of enthusiasm I found myself using the desk in sitting mode more often than not.

This month’s project was my attempt to rectify that. Using a cheap ultrasonic distance sensor and a Spark Core microcontroller – now known as a Particle Photon, following a major rebranding exercise – I built a device which could track the distance between the surface of the desk and the ceiling and thus report whether it was in sitting or standing mode. When a mode change was detected, it would post a message to Twitter – thus publicly shaming me if I spent too long in sitting mode.

It’s a bit of a daft project, but one which demonstrates some useful techniques: it uses a resistor ladder to lower the 5V output from the ultrasonic sensor to a Spark Core-friendly 3.3V, it shows how a Wi-Fi-connected microcontroller can report readings to a remote system, and even uses If This Then That (IFTTT) to automatically post messages to Twitter based on those readings. As to whether it actually encouraged me to spend more time standing? Not so much.

As the tutorial’s complexity meant taking up a three-page spread, there was only room for one additional feature this month: a two-page long-term review of the Tenma 60W Digital Soldering Station, which I bought some time ago to replace my Maplin-branded variable-output soldering iron. Despite its surprisingly reasonable cost, purchased from the ever-reliable CPC, it’s proven a sturdy tool and is an easy recommendation for anyone looking for an entry-level upgrade from fixed-output irons. It’s also a pleasure to be able to form a long-term opinion on something: all too frequently I review items on a short-term basis, which reveals nothing about their reliability over time. Having been using the Tenma for well over a year now, though, I can personally guarantee its longevity.

All this, plus a variety of interesting things written by people who aren’t me, can be yours at your local newsagent, supermarket, or electronically via Zinio and similar digital distribution services.

The MagPi, Issue 40

The MagPi Issue 40This month’s MagPi, the official magazine of the Raspberry Pi Foundation, is just a little bit special: it is, to my knowledge, the first magazine ever to include a cover-mounted computer. The release of the magazine today also represents the launch of a brand-new Raspberry Pi model: the Raspberry Pi Zero.

I’ve been lucky enough to have been playing with the Pi Zero for some time, having worked on three of the hardware projects you’ll find between the covers of this extra-special issue. After peeling the Pi Zero from the cover, readers will be shown how to solder general-purpose input/output (GPIO) headers onto its otherwise extremely flat face, connect its serial port to a computer for use as a true random number generator (TRNG), and use it with an existing HAT add-on to act as a mood lamp.

The three projects I created for this issue were chosen from a long, long list. The Pi Zero is an exciting device: it features the same specifications as the Raspberry Pi Model A, but in a brand-new form factor a fraction of the size of the original. Naturally, some features have been cut: just like the Model A there’s no Ethernet chip, but there are also no CSI or DSI connectors and no analogue audio or video ports – though composite video is broken out to a solder pad for the adventurous. The ports that do remain have also been modified: the full-size HDMI port is replaced by a mini-HDMI, and the full-size USB port is a micro-USB port which requires a USB On-The-Go (OTG) adapter before it can be connected to standard USB peripherals.

In doing this, the Foundation has created a device that excites me even more than the full-size models. With a production cost so low that it can be cover-mounted on a high-street magazine, it’s now possible to put a full Linux computer in more project than ever before – and with a simple low-cost USB OTG adapter and a Wi-Fi dongle, it can be networked for a total outlay of well below $10. It is, in short, a game-changer, and I look forward to working on many more Pi Zero-related projects in the near future.

If that wasn’t enough, you’ll also find my review of the Tenma 60W Digital Soldering Station which has been my trusty companion in various projects over the last couple of years. It’s always nice to be able to give a device a good, long-haul test before drawing your conclusions and I’ve certainly put the miles in on the Tenma. As I warn in the review a hobbyist doesn’t strictly need a soldering station, but it does make life easier – and the low cost of this unit, purchased from CPC, makes it easy to recommend for those who fancy an upgrade.

All this, plus more – and, remember the cover-mounted Pi Zero – is available in your nearest WH Smith. The magazine itself is also available as a DRM-free PDF download from the official website, licensed under Creative Commons terms, but obviously you’ll have to buy a Pi Zero separately if you want to follow along with any of my projects.

The Official Raspberry Pi Projects Book

The Official Raspberry Pi Projects BookI’ve been writing for The MagPi, the official magazine of the Raspberry Pi Foundation, since its major relaunch under the editorial leadership of Russell Barnes. That’s long enough to have built up a reasonable amount of content – and it’s that content you’ll find the The Official Raspberry Pi Projects Book, published today under a Creative Commons licence.

Inside the 200 page book, which is available in print and as a DRM-free PDF download, you’ll find several pieces of my work. The first is entitled ‘Crowdfundings Greatest Hits,” an eight-page investigation of some of the biggest Pi-related crowd-funded projects around – and some of its biggest failures, too. This was a great piece to work on, involving plenty of research and interviews, and was the first to break the news that Azorean was relying on additional external investment to fulfil rewards in its Ziphius campaign – rewards which have still not been fulfilled, more than a year after its original launch date.

You’ll also find reprints of several of my reviews: there’s the Pimoroni Display-o-Tron 3000 add-on, the Weaved IoT remote access system, the 4Tronix Agobo low-cost robot chassis, Velleman’s 3D Printing Pen, and the excellent Swanky Paint from local coding outfit WetGenes. Naturally, each is accompanied by photography which is also published under a Creative Commons licence – and is, as always, available for reuse from my Flickr page.

This marks the first book to which I have contributed which is published under a Creative Commons licence, but it certainly won’t be the last. Allowing for free non-commercial reuse and encouraging sharing and copying, it’s an approach at the complete opposite end of the spectrum to that taken by most publishers – and one of which I heartily approve.

You can download The Official Raspberry Pi Projects Book for free from the official website, while print copies are available from the swag store or the usual high-street outlets.

Linux User & Developer, Issue 159

Linux User & Developer Issue 159My review for this month’s Linux User & Developer Magazine is the frankly impressive CompuLab Fitlet miniature PC, which joins my usual four-page news spread between the publication’s ever-colourful covers.

I first reviewed the Fitlet in Custom PC Issue 148, published last month, but where that review focused on the device’s suitability for the hobbyist and for general-purpose computing my version for Linux User naturally takes the perspective of a die-hard Linux… well, user. As a result, the fact that CompuLab supplied it with a pre-installed version of Linux Mint 17.2 was a bonus – although there’s nothing to stop you wiping the system and installing any other flavour you fancy, thanks to its entirely standard architecture.

Traditionally, driver support in Linux has always been a pain when it comes to shiny new hardware. I’ve lost count of the number of times I’ve had a device on the test-bench and found that it requires a bleeding-edge kernel or an array of patches to even boot – but not so the Fitlet. Everything, from the wireless to accelerated graphics, was working just fine out-the-box with the sole exception of the General Purpose Input-Output (GPIO) header – an oversight the company has since corrected with the release of an official SDK.

The sheer array of options on offer is enough to turn anyone’s head, too. Those who like an uncluttered desk will find the VESA bracket accessory a must-have; others might find the DIN rail mount a better choice; still more could opt for the larger passive heatsink to overclock the CPU – a one-setting feature directly in the BIOS, requiring no modification and with no effect on warranty – to wring some more performance out. It’s even possible to spec the Fitlet with different ports thanks to its modular Function And Connectivity Extension T-card (FACET) system: the dual-Ethernet single-eSATA default can be quickly modified to quadruple-Ethernet, if that’s your sort of thing.

It’s fair to say I’m a big fan of the Fitlet, and to read the review in full – plus all the latest happenings in the world of open source – all you need do is head to your nearest newsagent or supermarket, or download the issue digitally via Zinio or similar services.