Custom PC, Issue 133

Custom PC Issue 133This month’s Hobby Tech is an absolute giant: seven pages long, owing to a bonus two-page review of the Nvidia Jetson TK1 development board – and many thanks to the guys at Zotac for granting me exclusive access to the UK’s only press sample ahead of its retail launch! The usual five pages are filled with a tutorial on using relays with the Raspberry Pi, an in-depth look at the Phenoptix MeArm, and a tour of the excellent DOSBox software.

The Jetson TK1 is a good place to start. It’s no Raspberry Pi: launching at £199.99 via Maplin – despite a far lower $192 US RRP – the board is designed for developers with big pockets. Despite this, it may actually be worth the cash: it’s by far the fastest single-board computer I’ve ever had on my test bench, with four 2.3GHz Cortex-A15 CPU cores, a fifth ‘Shadow Core’ for background tasks, and 192 Kepler-class graphics processing cores on its sadly actively-cooled chip. There are, however, issues that will trouble hobbyists looking to use the system. Most surprising of these is a lack of OpenCL support, despite the Tegra K1 on which the Jetson TK1 is based supporting it just fine.

From the high-end to the pocket-friendly with the next review: the Phenoptix MeArm. Supplied by Ben Gray, its designer, the MeArm is a kit of laser-cut acrylic parts and a selection of hobby servos for building a desktop robotic arm. Compatible with anything that can drive servos – or even things, like the Raspberry Pi, that can’t, if you add an I2C controller board – the MeArm is a fascinating entry point to hobbyist robotics, and doubly so thanks to its open nature and extremely low cost.

The tutorial this month is an extension to the Twitter-connected doorbell which appeared in Issue 130. Although the original design worked fine, it lacked an audible alert. The solution: using a relay to trigger the original doorbell’s sounder unit, turning my design into a drop-in upgrade for any wired doorbell while also teaching the basics of how relays can extend the capabilities of a microcontroller or microcomputer platform.

Finally, DOSBox. While I’m a big believer in using real-metal hardware for my vintage computing, even I have to admit that sometimes emulators can be extremely handy – and DOSBox is one of the handiest around. More properly termed a simulator, DOSBox allows you to run old MS-DOS software on modern systems – complete with filters that improve the graphics and full network support. Designed primarily for gaming, its compatibility with images created using the KryoFlux – reviewed in Issue 131 – mean it’s perfect for retrieving data from ageing floppy disks, as well as playing Doom the way it should be played!

All this, plus a bunch of other interesting things written by people who aren’t me, can be yours with a trip to your nearest newsagent or supermarket. If you’d prefer not to leave the house, try a digital copy via Zinio or similar services.

Custom PC, Issue 125

Custom PC Issue 125In this most recent issue of my eponymous column, Gareth Halfacree’s Hobby Tech, I take an all-too-rare field trip to my local Hackspace, investigate a “sold as seen” Famiclone, and review the Dangerous Prototypes ATX Breakout Board.

First, the review. Kindly provided by the lovely people at Phentopix, the ATX Breakout Board was designed by Dangerous Prototypes to address the biggest issue surrounding bench power supplies in the hobbyist market: they’re all either crap, or frustratingly expensive. By tapping into a standard ATX PSU – the exact same type you’d fine inside any desktop computer from the last decade and more – the kit provides a range of voltages at a surprisingly capable amperage, and all for a fraction of the cost of a true bench power supply.

Each major rail of the PSU – 3.3V, 5V, 12V and a handy -12V for audio components – is broken out to screw terminal banana sockets, to which the user can connect bare wires or their own test leads. For those lucky enough to have a working ATX PSU from the 90s, there’s also a -5V connection – but, sadly, this rail was removed in most modern units. That said, it’s still a wide range of voltages, and the board includes over-current protection, a dedicated power switch and even room for a bundled resistive load to be soldered on for the rare PSUs that won’t start unloaded.

I have to admit, when the board arrived – complete with very attractive transparent housing designed by Phenoptix and cut on the in-house laser – I wasn’t sure it would be up to the job. It’s small, it’s simple, and it’s cheap – but it has also all-but replaced my real bench-top PSU for everything that doesn’t need precise current control or strange voltage steps.

Next, the Good Boy. A ‘Famiclone’ – the colloquial name given to unauthorised replicas of Nintendo’s Family Computer, or Famicom – purchased from eBay for a few quid ‘untested,’ I wasn’t expecting much and boy did I get it. The Good Boy proved a perfect example of why it’s important to do a physical check before powering up second-hand machines of unknown provenance: someone somewhere had given it far more power than it could handle, and several components had quite literally exploded. For now, it’s on the to-do pile awaiting replacement parts.

Finally, my visit to Leeds Hackspace. A community-led club for programmers, hackers, gamers, electronics enthusiasts, engineers, makers, and the plain curious, Leeds Hackspace is one of a growing number – known in the US as Hackerspaces – around the world. Every Tuesday, the club runs an open evening where non members are welcome to attend, use the equipment, chat and receive help – as do most other Hackspaces.

If you’re hacker-minded, going to a Hackspace is like being let loose in a sweet shop: there are oscilloscopes, laser cutters, 3D printers, drill presses, and a variety of other pieces of equipment most of us don’t have room for in our houses or wallets; there are projects on display like converted arcade machines, automated Nerf turrets, kids’ toys, railway station display boards, and Bitcoin mining rigs; and there are the people.

It’s the people, in fact, that really make a Hackspace. Welcoming and inclusive, the guys and gals at Leeds Hackspace are some of the friendliest people I’ve ever met and always willing to show off their latest projects or give a newbie a hand. It’s convinced me, in fact, that in the new year I should really investigate a paid-for membership – even if it is annoyingly far away, there being no Hackspace yet founded in Bradford.

All this, plus the usual snippets of news from the world of the maker, can be found in Custom PC Issue 125 at your local newsagent, supermarket, delivered by subscription or digitally via Zinio and similar services. Oh, and if you’re quick you’ll be able to use the team’s annual Mince Pie Megatest to make your Christmas dinner go off with a sweet treat.