Custom PC, Issue 174

Custom PC Issue 174This 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.

Custom PC Magazine, Issue 158

Custom PC Magazine Issue 158This month, my regular Hobby Tech column is interview-heavy. You’ll find two pages dedicated to Grant Macaulay of Theo Lasers, another two to Barry Getty of the Dark Water Foundation, and a final page reviewing the Genuino Zero microcontroller simply for a change of pace.

First, Grant. I met Grant at the recent Maker Faire UK, where he was showcasing prototypes of the Theo Laser laser cutters. These devices immediately caught my eye: rather than the usual red or beige metal, the cases were made from unfinished laser-cut wood. Each housed a low-power diode laser, and the top-end model was set to retail for around £1,000. A few months later Grant was getting ready to hit the go-live button on a Kickstarter campaign to fund the project, and kindly took some time to walk me through his hopes for Theo Lasers – not to mention the thinking behind his decision to release everything from the hardware designs to the source code under a permissive, open-source licence.

Barry’s another contact from an event: Liverpool MakeFest 2015. There, I talked to Barry as his Dark Water Foundation ran a Lego-based workshop teaching the young and the not-so-young how to build open-source remote-operated submersible vehicles (ROSVs). Like Grant, Barry’s work didn’t stop when my original interview ended and I recently caught up with him to discuss some new designs: the Dark Control boards. Designed for use with the Raspberry Pi, these add-on boards allow for connecting up to six motors – important, he tells me, for full freedom of movement – quickly and easily, while also adding support for radio control systems and inertial measurement units.

Finally, the Genuino Zero. Kindly provided by oomlout as part of a collection of hardware I’m slowly working my way through testing, the Genuino Zero – known as the Arduino Zero in the US – drops Arduino’s traditional 8-bit ATmega microcontroller family in favour of a 32-bit ARM Cortex-M0+. The result is a board that looks for all the world like an Arduino Uno, but which offers considerably different capabilities and improved performance.

All this, and the usual selection of interesting things written by people who aren’t me, can be found in your nearest supermarket, newsagent, or electronically via Zinio and similar digital distribution platforms.