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

Custom PC, Issue 153

Custom PC Issue 153My regular Hobby Tech column celebrates its third year this month, and I’d like to think it does so in style. As well as a two-page review of the Raspberry Pi 3, the column details how to build a Raspberry Pi Zero-based energy usage graph into a cheap box frame and interviews Raspberry Pi Foundation director of hardware James Adams about his designs and inspiration.

First, the Pi 3. I’ve previously written about the board in a cover feature for The MagPi and in Linux User & Developer, so there should be no major surprises in this review – beyond a focus more on the hobbyist community’s desires and concerns, given the title of the column. The interview, though, is all-new: a small, separate extract of my interview was published in The MagPi’s Raspberry Pi 3 launch issue, but the material used in Hobby Tech is fresh – including detailed information on just how that Wi-Fi and Bluetooth radio module talks to the new BCM2837 SoC and the challenges of conformance testing something that has an intentional radio emitter inside.

The build was a project I worked on after picking up a cheap electricity and gas monitor for my house. While the website works well for viewing live usage and historical graphs, I wanted something that wouldn’t look out of place in the living room and hopefully remind everyone to turn things off when they leave! A cheap Raspberry Pi Zero was the perfect platform, and combine with a Pimoroni Unicorn HAT fits snugly in the back of a wooden box frame. Some paper on the front diffuses the LEDs to prevent glare and make it look less like a hack and more like a piece of furniture – though with the consequence that the photos look a little washed out compared to the bright, colourful display in the flesh – and everything else is a software concern.

All this, and interesting things written by people who aren’t me, is available from your local supermarket, newsagent, or electronically via Zinio and similar services.

Linux User & Developer, Issue 164

Linux User & Developer Issue 164My review for this month’s Linux User & Developer magazine is of a device I’ve been playing with for a while now: the Raspberry Pi 3, the first single-board computer from the Raspberry Pi Foundation to include a 64-bit CPU and integrated radio chip.

Following my cover feature for The MagPi magazine, the Raspberry Pi 3 once again graces a magazine cover – and well it should. The switch from ARM Cortex-A7 to ARM Cortex-A53 processors cores in the new Broadcom BCM2837 system-on-chip (SoC) brings with it a considerable performance boost over the Raspberry Pi 2, which itself left the original single-core Raspberry Pi in the dust.

That’s even before discussing the integrated wireless connectivity. Boasting 2.4GHz Wi-Fi, Bluetooth 4.1, and Bluetooth Low Energy, the Raspberry Pi 3 certainly ticks a lot of boxes on the connectivity front – even if the integrated Ethernet port still communicates with the SoC through a shared single USB channel. Best of all, the board is entirely compatible with accessories and software written for earlier models – going all the way back to the early raft of add-ons for the original Raspberry Pi.

One discovery that cropped up between the MagPi launch feature and this review, though, was heat generation: testing under my thermal camera, published on imgur for the curious, revealed that the Raspberry Pi 3 gets considerably hotter than its predecessors – over 100°C under CPU load. This leads to a couple of issues: potential burns if you poke the chip and thermal throttling which dramatically harms performance if the Pi 3 is installed in a case. Coupled with even harsher throttling – from 1.2GHz to just 600MHz – when used with marginal power supplies or low-quality micro-USB cables, there are caveats aplenty.

For the full low-down, pick up a copy of Linux User & Developer Issue 164 from your nearest supermarket, newsagent, or electronically via services such as Zinio.

Linux User & Developer, Issue 163

Linux User & Developer Issue 163This month’s Linux User & Developer includes my review of the Arduino-produced and Intel-chip-toting Genuino 101 microcontroller and the final five-page news spread, with publisher Imagine shuffling things around and taking the news coverage in-house after lo these many years.

Kindly supplied as a press sample by Intel, the Genuino 101 is special for a number of reasons. Firstly, it’s one of the first commercially-available devices to be sold under the new Genuino brand outside the US – a necessity thanks to some hairy legal wrangling between two competing companies who have a claim to the Arduino trademark. Secondly, it’s the first outing for Intel’s new Curie module, a wearable-centric system-on-chip that combines microcomputer and microcontroller functionality.

Where Intel’s previous efforts at developing boards for the maker market have been somewhat hard to love, it’s definitely doing something right with the Genuino 101. The board is based on the popular Arduino Uno layout, includes 5V-safe pins despite running 3.3V logic, and can run most Arduino sketches unmodified. Better still, the Curie module includes integrated Bluetooth Low Energy support and an accelerometer sensor.

The design of the chip, though, is odd, and it’s something on which I focus during the review: the Curie uses two processors, an x86 Quark based on the old Pentium microarchitecture to run an underlying real-time operating system (RTOS) and an Argonaut RISC Core (ARC) which takes care of being a microcontroller and actually running the Arduino sketch. At the time of writing, the divide was stark: the Quark is entirely locked off from user access, taking over automatically for tasks like Bluetooth communication when requested by the ARC. While Intel has promised to release the source for the RTOS, allowing users to run their own code on the Quark as well as the ARC, this has yet to materialise.

Despite this, I was impressed with the Genuino 101 – but to read my full conclusion, you’ll have to hie thee hence to a supermarket, newsagent, or snag an electronic copy via Zinio or similar digital distribution services.

Custom PC, Issue 152

Custom PC Issue 152In this month’s Hobby Tech column I review the Proster VC99 multimeter, the Intel/Arduino Genuino 101 microcontroller development board, and discuss the challenges in developing meaningful benchmarks for testing devices where memory is measured in kilobytes.

Unusually for a hardware review, the multimeter was actually a personal purchase: I’d been using a Maplin-branded multimeter for quite some time, but the low cost and seemingly broad features of the Proster VC99 – also known as the Vichy 99, and sold under a variety of badges – convinced me it was time for an upgrade. While doing so cost me a back-lit display, I gained a variety of functions from frequency counting up to a neat analogue bar-graph on the display for seeing spikes and dips that would otherwise be lost on a numerical output.

The frequency counter came in particularly handy for my Genuino 101 review: writing a simple Arduino Sketch which does nothing more than toggle a pin on and off as fast as possible, I was able to read how quickly that happened to give me an idea of the IO performance of the Genuino compared with other Arduino boards I have lying around. Coupled with a look at the Intel Curie module which powers the device, providing Bluetooth connectivity and an integrated accelerometer, that’s enough for a solid review.

I don’t want to do solid reviews, though, I want to do great reviews, so the last page of this month’s five-page spread looks at how I benchmarked the compute performance of the Genuino 101 against an Arduino Nano for a direct, head-to-head comparison. It’s not as easy as it sounds: with mere kilobytes of memory, it’s not like I could just install PC Mark and be done with it. Interested parties will find a detailed explanation of how I went about modifying the traditional Dhrystone and Whetstone benchmarks to run on both devices, including trimming things to fit into the Arduino Nano’s tiny memory allowance, and how to interpret the results.

All this, plus stuff by people who aren’t me, is available at your nearest supermarket, newsagent, or from the comfort of your home via digital distribution services including Zinio.

The MagPi, Issue 43

The MagPi Issue 43It’s a special week for the Raspberry Pi Foundation: it’s celebrating its fourth birthday with the launch of the new Raspberry Pi 3. It’s a special day for me, too: the latest MagPi magazine boasts a total of thirteen pages of my content, including the cover splash: a detailed and thorough look at the new model.

Boasting on-board Wi-Fi (a community request since the original model launched four years ago), Bluetooth 4.1, Bluetooth Low Energy, and a faster 64-bit ARMv8 processor, the new Pi 3 is a bit of a beast. My cover feature for the magazine begins with a look at those behind it with a double-page spread featuring interviews with project co-founder Eben Upton and the Foundation’s director of hardware and the man responsible for circuit design James Adams – and a massive thank-you to both for sparing the time to talk to me at one of their busiest ever periods!

The feature then moves on to a look a the board itself, with a hero photo of the board spread across another two pages. Each major feature of the board, from the shiny new 64-bit BCM2837 system-on-chip (SoC) processor to the BCM43438 radio module – which required me to get out the microscope in order to capture its markings – has a call-out with close-up photography and an explanation of how it has changed since the Raspberry Pi 2.

Next up is a benchmark spread, which required me to come up with a detailed suite of tests. After some experimentation, I settled on a selection of classic benchmarks – SysBench CPU in single- and multi-threaded modes, Linpack with and without NEON support, Whetstone, Dhrystone, SysBench memory read and write, Ethernet throughput, Quake III Arena timedemo performance, and power draw at load and idle. As an added bonus, I also came up with a way of measuring general-purpose input-output (GPIO) performance under Python, writing a simple benchmark to toggle a pin on and off as quickly as possible and measuring the speed with a frequency counter connected to the GPIO header.

The next double-page spread looks at helping the reader get started with the new device. I walk readers through modifying an existing Raspbian installation to boot on the Pi 3 by editing config.txt, setting up the Wi-Fi module, enabling true OpenGL acceleration on the graphics processor, and how to write programs to get the best performance on the Pi 3. Sadly, I was unable to explain how to use the Bluetooth 4.1 and Bluetooth Low Energy features, as software support was not available at the time of writing.

The spread then ends with a look at five things you could do with a Pi 3 in order to take advantage of the new features and boosted performance. My work for the magazine continues, though, with a review of the Proster VC99 multimeter and Pimoroni pHAT DAC, before coming to a close with a one-page news piece regarding the production status of the popular Raspberry Pi Zero – helping to explain why it has been so difficult to get hold of and settling concerns that it may be bumped to the back of the production queue now the Pi 3 is out.

All 13 pages of my content, and plenty of other stuff by people who aren’t me, are available from your nearest supermarket or newsagent, or as a free PDF download under a Creative Commons licence from The MagPi’s official website.

Linux User & Developer, Issue 162

Linux User & Developer Issue 162In addition to my regular four-page news spread, this month’s Linux User & Developer features a review of a maker-oriented computer-on-module (COM): the LeMaker Guitar.

The Guitar comes from the same company that brought us the Banana Pro, but while LeMaker has ditched its fruit-themed product nomenclature it’s still drawing inspiration from the same source: the Guitar the Chinese company’s equivalent to the Raspberry Pi Compute Module, based on the same SODIMM-layout module design and featuring a bundled break-out board to make the device’s features more accessible to hobbyists.

Where it improves on the Compute Module’s design is in its specifications: an Action system-on-chip (SoC) processor proves considerably more capable than the ageing BCM2835 of the Raspberry Pi Compute Module, there’s more RAM, and it even has Wi-Fi connectivity – though this, sadly, is based on a module attached to the break-out board, meaning that it’s not something you’ll have available should you decide to build your own circuit with the Guitar module at its heart.

When I reviewed the device, I was particularly impressed with the performance for the price – especially given that the Compute Module is considerably more expensive than the Guitar. In the time since the review, though, retailers have significantly discounted the Compute Module ahead of the planned launch of a 64-bit, 1.2GHz Compute Module 3 later this year based on the same BCM2837 SoC as the newly-launched Raspberry Pi 3. If you’re not in a rush, in other words, it may be worth seeing how much the Compute Module 3 costs before designing anything around the Guitar.

The full review, along with my four-page news spread, can be found gracing the shelves of your nearest supermarket, newsagent, or as a series of zeroes and ones on digital distribution services including Zinio.

Custom PC, Issue 151

Custom PC Issue 151In my latest Hobby Tech column for Custom PC, I take a look at the Pi Zero-specific pHAT family of add-on boards from local electronics wizards Pimoroni, review the Guitar computer-on-module from China’s LeMaker, and show readers how to enhance a Raspberry Pi with a simple reset-stroke-power switch.

Firstly, the pHATs. The launch of the Raspberry Pi Zero, reviewed in last month’s Hobby Tech, brought with it the opportunity for Pi experts like Pimoroni to come out with some add-on devices matching the same form factor – which is, unsurprisingly, exactly what the company has done. The result is a family of, at the time of the review, three tiny add-on boards: the Explorer pHAT, Scroll pHAT, and pHAT DAC. Each comes with unpopulated GPIO, giving the user the option of soldering on the bundled female header for the ability to easily remove the device or soldering it directly to a Pi Zero to make an ultra-compact electronic sandwich.

The Explorer pHAT is the most versatile of the bunch, adding 5V outputs, inputs, analogue inputs, and even a pair of motor control channels to the Pi’s otherwise feature-light 3.3V GPIO header. The Scroll pHAT, meanwhile, features some bright white LEDs in a 5×11 matrix and comes with software for scrolling messages. Finally, the pHAT DAC is an ultra-compact digital to analogue converter capable of playing back 192KHz 24-bit audio via a pre-fitted 3.5mm jack or optional pair of RCA jacks. In short: there’s a little something for everyone.

The Guitar is LeMaker’s follow-up device to what was previously known as the Banana Pi – and, like its predecessor, LeMaker is taking design cues from the Raspberry Pi Foundation. This time, it’s made a Compute Module-alike: a small SODIMM-layout computer-on-module which comes bundled with a break-out board to access its various features. Considering the high price of the official Compute Module, I had high hopes for the budget-friendly Guitar – and I’m pleased to say that it mostly didn’t disappoint.

Finally, the reset switch tutorial. A variant of the tutorial I prepared for The MagPi tailored specifically to the Custom PC audience, it walks the reader through adding a simple switch to any Raspberry Pi – but focusing on the new Zero – in order to quickly reset the device in the event of a crash. As an added bonus, it also allows you to power the Pi on from a shut-down state.

All this, plus a bunch of stuff written by people other than me, can be yours in Custom PC Issue 151. Either pick up a physical copy from wherever magazines congregate, or snag it digitally via Zinio or similar distribution services.

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.