Custom PC, Issue 126

Custom PC Issue 126My monthly Custom PC column, Gareth Halfacree’s Hobby Tech, continues with a look at the toys and projects that have been entertaining me over the past four weeks including the acquisition of a core memory module, the Raspberry Pi GertDuino add-on board, and a guide – teased on the cover splash – to mining the Bitcoin cryptocurrency on said Pi.

First, the GertDuino. I won’t repeat myself with a summary of the device’s features – which are readily available in my review summary for Linux User & Developer Issue 135 – except to say that, as is usual for reviews in Hobby Tech, the review is written from a very personal perspective. As a result, the reader can enjoy a summarised version of my first few days with the device – including the heartache I had getting the blessed thing to work with the Arduino integrated development environment (IDE).

For the usual vintage computing portion of the column, I took a look at a new – to me – acquisition: a core memory module, pulled from a Soviet-era industrial computer of some description. The predecessor to modern transistor-based memory, magnetic core – literally a mesh of magnetic toroids which can be flipped to hold either a 0 or a 1 – has had an inestimable impact on modern computing, to the point where even today the process of saving memory contents to permanent storage for review is known as a ‘core dump.’

Also, the thing looks amazing under a microscope.

Finally, this month’s semi-regular tutorial section looks at using a USB-connected application specific integrated circuit (ASIC) to rapidly mine the Bitcoin cryptocurrency on a low-power Raspberry Pi. Prompted by my good friend Martyn Ranyard – the joint owner of a considerably more powerful mining rig than the one I created – the tutorial walks the reader through the exact steps I took to add Bitcoin mining facilities to my multipurpose Pi-based home server.

All this, plus a bunch of interesting stuff written by people who aren’t me, can be yours with a trip to your local supermarket, newsagent or a digital purchase on distribution services like Zinio. If you’d rather not risk missing an issue, Dennis Publishing is currently offering subscriptions at 50 per cent off the normal rate until the 31st of January.

Linux User & Developer, Issue 135

Linux User & Developer, Issue 135In Linux User & Developer this month, in addition to my usual four-page spread of the latest news from the open source, open hardware and open governance spheres, you’ll find a review of a new add-on board for the Raspberry Pi: the GertDuino.

Developed by Gert van Loo, the GertDuino is a slimmed-down and simplified design based on the microcontroller-powered portion of the Gertboard – originally reviewed way back in Linux User & Developer Issue 121 from December 2012. Unlike the Gertboard, the Gertduino is a zero-footprint design which sits entirely on top of the Pi to expand the capabilities of its general-purpose input-output (GPIO) header.

Powered by a pair of Atmel microcontrollers – a primary ATmega328 and a secondary ATmega48 – the GertDuino offers full compatibility with Arduino Shield add-on boards, the ability to run stand-alone in Arduino mode, and a variety of other snazzy features including an on-board real-time clock with optional battery backup and a bidirectional IrDA interface. Both these latter features are powered by the ATmega48, allowing the more technically minded user to put the Pi and the ATmega328 into a low-power sleep mode pending a wake-up interrupt from the ATmega48.

There’s no denying the Gertboard is a clever design, but it does fall into several of the traps of its predecessor. Switching between the board’s various modes is achieved using unlabelled jumpers, while one of the most handy modes – the ability to query Arduino Shields which use serial communications directly from the Pi – requires optional jumper straps which then get in the way of mounting the Shield itself. Documentation, too, is poor – and aimed primarily at those with embedded development or C coding experience already.

Is it worth the price of admission? Well, you’ll have to buy Linux User & Developer Issue 135 to find out – either from your local newsagent, supermarket, or digitally via Zinio and similar distribution platforms.