Silicon ChipMax’s Cool Beans - February 2020 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Subscriptions: PE Subscription
  4. Publisher's Letter
  5. Feature: The Fox Report by Barry Fox
  6. Feature: Techno Talk by Mark Nelson
  7. Feature: Net Work by Alan Winstanley
  8. Project: Audio DSP by Design by Phil Prosser , Words by Nicholas Vinen
  9. Project: Motion-Triggered 12V Switch by Nicholas Vinen
  10. Project: USB Keyboard and Mouse Adaptor for Micros by Tim Blythman
  11. Project: Stamp-sized digital audio player by Jim Rowe
  12. Project: Colour Maximite Computer
  13. Feature: Circuit Surgery by Ian Bell
  14. Feature: Practically Speaking by Mike Hibbett
  15. Feature: Using Stepper Motors by Paul Cooper
  16. Feature: Max’s Cool Beans by Max the Magnificent
  17. Feature: AUDIO OUT by Jake Rothman
  18. Feature: Make it with Micromite by Phil Boyce
  19. Feature: Electronic Building Blocks by Julian Edgar
  20. PCB Order Form
  21. Advertising Index

This is only a preview of the February 2020 issue of Practical Electronics.

You can view 0 of the 80 pages in the full issue.

Articles in this series:
  • Techno Talk (February 2020)
  • Techno Talk (February 2020)
  • Techno Talk (March 2020)
  • Techno Talk (March 2020)
  • (April 2020)
  • (April 2020)
  • Techno Talk (May 2020)
  • Techno Talk (May 2020)
  • Techno Talk (June 2020)
  • Techno Talk (June 2020)
  • Techno Talk (July 2020)
  • Techno Talk (July 2020)
  • Techno Talk (August 2020)
  • Techno Talk (August 2020)
  • Techno Talk (September 2020)
  • Techno Talk (September 2020)
  • Techno Talk (October 2020)
  • Techno Talk (October 2020)
  • (November 2020)
  • (November 2020)
  • Techno Talk (December 2020)
  • Techno Talk (December 2020)
  • Techno Talk (January 2021)
  • Techno Talk (January 2021)
  • Techno Talk (February 2021)
  • Techno Talk (February 2021)
  • Techno Talk (March 2021)
  • Techno Talk (March 2021)
  • Techno Talk (April 2021)
  • Techno Talk (April 2021)
  • Techno Talk (May 2021)
  • Techno Talk (May 2021)
  • Techno Talk (June 2021)
  • Techno Talk (June 2021)
  • Techno Talk (July 2021)
  • Techno Talk (July 2021)
  • Techno Talk (August 2021)
  • Techno Talk (August 2021)
  • Techno Talk (September 2021)
  • Techno Talk (September 2021)
  • Techno Talk (October 2021)
  • Techno Talk (October 2021)
  • Techno Talk (November 2021)
  • Techno Talk (November 2021)
  • Techno Talk (December 2021)
  • Techno Talk (December 2021)
  • Communing with nature (January 2022)
  • Communing with nature (January 2022)
  • Should we be worried? (February 2022)
  • Should we be worried? (February 2022)
  • How resilient is your lifeline? (March 2022)
  • How resilient is your lifeline? (March 2022)
  • Go eco, get ethical! (April 2022)
  • Go eco, get ethical! (April 2022)
  • From nano to bio (May 2022)
  • From nano to bio (May 2022)
  • Positivity follows the gloom (June 2022)
  • Positivity follows the gloom (June 2022)
  • Mixed menu (July 2022)
  • Mixed menu (July 2022)
  • Time for a total rethink? (August 2022)
  • Time for a total rethink? (August 2022)
  • What’s in a name? (September 2022)
  • What’s in a name? (September 2022)
  • Forget leaves on the line! (October 2022)
  • Forget leaves on the line! (October 2022)
  • Giant Boost for Batteries (December 2022)
  • Giant Boost for Batteries (December 2022)
  • Raudive Voices Revisited (January 2023)
  • Raudive Voices Revisited (January 2023)
  • A thousand words (February 2023)
  • A thousand words (February 2023)
  • It’s handover time (March 2023)
  • It’s handover time (March 2023)
  • AI, Robots, Horticulture and Agriculture (April 2023)
  • AI, Robots, Horticulture and Agriculture (April 2023)
  • Prophecy can be perplexing (May 2023)
  • Prophecy can be perplexing (May 2023)
  • Technology comes in different shapes and sizes (June 2023)
  • Technology comes in different shapes and sizes (June 2023)
  • AI and robots – what could possibly go wrong? (July 2023)
  • AI and robots – what could possibly go wrong? (July 2023)
  • How long until we’re all out of work? (August 2023)
  • How long until we’re all out of work? (August 2023)
  • We both have truths, are mine the same as yours? (September 2023)
  • We both have truths, are mine the same as yours? (September 2023)
  • Holy Spheres, Batman! (October 2023)
  • Holy Spheres, Batman! (October 2023)
  • Where’s my pneumatic car? (November 2023)
  • Where’s my pneumatic car? (November 2023)
  • Good grief! (December 2023)
  • Good grief! (December 2023)
  • Cheeky chiplets (January 2024)
  • Cheeky chiplets (January 2024)
  • Cheeky chiplets (February 2024)
  • Cheeky chiplets (February 2024)
  • The Wibbly-Wobbly World of Quantum (March 2024)
  • The Wibbly-Wobbly World of Quantum (March 2024)
  • Techno Talk - Wait! What? Really? (April 2024)
  • Techno Talk - Wait! What? Really? (April 2024)
  • Techno Talk - One step closer to a dystopian abyss? (May 2024)
  • Techno Talk - One step closer to a dystopian abyss? (May 2024)
  • Techno Talk - Program that! (June 2024)
  • Techno Talk - Program that! (June 2024)
  • Techno Talk (July 2024)
  • Techno Talk (July 2024)
  • Techno Talk - That makes so much sense! (August 2024)
  • Techno Talk - That makes so much sense! (August 2024)
  • Techno Talk - I don’t want to be a Norbert... (September 2024)
  • Techno Talk - I don’t want to be a Norbert... (September 2024)
  • Techno Talk - Sticking the landing (October 2024)
  • Techno Talk - Sticking the landing (October 2024)
  • Techno Talk (November 2024)
  • Techno Talk (November 2024)
  • Techno Talk (December 2024)
  • Techno Talk (December 2024)
  • Techno Talk (January 2025)
  • Techno Talk (January 2025)
  • Techno Talk (February 2025)
  • Techno Talk (February 2025)
  • Techno Talk (March 2025)
  • Techno Talk (March 2025)
  • Techno Talk (April 2025)
  • Techno Talk (April 2025)
  • Techno Talk (May 2025)
  • Techno Talk (May 2025)
  • Techno Talk (June 2025)
  • Techno Talk (June 2025)
  • Techno Talk (July 2025)
  • Techno Talk (July 2025)
Max’s Cool Beans By Max the Magnificent The wanters, the wishers, and the makers! don’t see those everyday), the Arduino was announced, MAKE magazine was launched, and the Maker Movement was born. These days it’s hard to swing a stick without hitting a maker (not that this is a practice I advocate, you understand). Now I have friends (one day I’ll tell them). One of the great things about what I do – freelance technical consulting and writing – is that I get to meet a lot of interesting folks, including magnificent makers. In my previous column I introduced you to the aptly named Nick Bild in the US. In this column, I’d like you to say ‘Hello’ to Richard Grafton in the UK (Fig.1.). The following is in Richard’s own words. Say hi to Richard Grafton Fig.1. Richard Grafton flaunting a cheesy smile to go with his breadboard computer. H ere’s a quote close to my heart: “Three categories of people exist in the world; ‘the wanters’, ‘the wishers’, and ‘the makers’.” (101 Keys to Everyday Passion by Israelmore Ayivor, see: https://amzn.to/2R2JfGq). I’ve been making things for as long as I can remember. Some of them even worked. I only wish we’d had the Internet or someone to mentor me when I was a kid; my dear old dad was hard pushed to replace a fuse. One Christmas, when I was about 10 years old, my parents gave me one of those electronics kits that involved a lot of springs – a simpler version of the ‘Electronic Playground and Learning Center’ I just found on Amazon (https://amzn.to/2QVxLEM). It also came with a book that talked about things like ‘resistor bridges,’ which made no sense whatsoever to my uninformed brain. Lacking someone to guide me, I’m surprised I survived the experience. By the time I was 12, my parents had taken out subscriptions to Practical Electronics and Practical Wireless magazines. I hoarded my pocket money (allowance), and at the beginning of each month I’d keep popping into the newsagent at the bottom of the road on the way home from school to see if either of these magazines had arrived. As soon as I had one Practical Electronics | February | 2020 in my sweaty hands, I would sit on the wall outside the newsagents reading it. If there was a simple project (typically something that made a lot of noise) that looked interesting and was within my budget, I‘d hop on a bus and go to a dingy backstreet electronics components store called Bardwells (http://bit. ly/pe-feb20-bdwls), purchase all of the bits and pieces, then return home and disappear into my bedroom for a few hours until – eventually – strange and annoying sounds would ensue. A lot of my friends at that time made ‘stuff.’ I thought making things was a common practice. The 1970s were the heyday of the Heathkit when it was cheaper to build something than to buy it, and there were little TV and Radio repair shops all over the place. Then things started to change. It became cheaper to buy things than to build them, and easier to replace something than to fix it. Companies making electronic kits started to close down, DIY magazines started to disappear from the newsagent’s shelves, and people in general seemed to lose interest in making things. I was sad. I thought I was all alone. A little tear rolled down my cheek. I tried to be brave. Then, suddenly, circa 2005, with a fanfare of metaphorical trumpets (you I suppose I’ve been a ‘maker’ all my life. I remember from a very early age inventing things that popped into my imagination – usually with Lego Technic or anything around the house I could get my hands on. At around the age of 14, I recall finding a book introducing Visual Basic 5 (complete with the software on CD). My curiosity got the better of me; I fired up Windows 95 and started playing with it. Somehow, I intuitively understood what it was all about, and realised I could actually ‘make’ stuff using a computer. Of course, this opened up a whole world of exciting possibilities. My crowning glory was writing a (pretty crude) encrypted messaging program which I distributed to my school friends on floppy disks (marked ‘Maths Homework’) so we could chat over the school’s computer network without being detected. It worked pretty well too! I suppose this was when I got excited about making stuff that other people could use. All this fun culminated in me doing an interdisciplinary informatics and engineering degree at the University of Sussex (which I loved from beginning to end). At the time, I was often surprised to find out that I already knew parts of the computing curriculum because I’d already self-discovered the algorithm or design principle through my Visual Basic tinkering – I just hadn’t considered at 14 that there’d already be names for these things or that I’d have to rehash my early software discoveries later on in life to pass exams! 59 This seed of inspiration is how I ended up tinkering away on a kitchen table late into the evening over a period of several weeks. What emerged was a humble 4-bit arithmetic unit designed using 7400 series integrated circuits – you can think of it as a simple binary calculator. This was the embryo of the first ARITH-MATIC product: the S1-AU Mk1 (Fig.2.). As a self-confessed geek this was all great fun for me, but according to my partner it was not sustainable to hog the kitchen table! To avoid any inevitable conflict, I moved the project into a shared studio space and slowly developed a series of prototypes. After quite a few redesigns and failures, what emerged were three DIY electronic kits that dissect the complex mechanisms of computation. I had learnt so much over this period of time and undertaken so much R&D that I realised this Fig.2. The S1-AU Mk1 4-bit arithmetic unit. After my time at Sussex, I decided to go into research so I could continue making stuff. I then spent two years training at BBC R&D (learning how to do all this engineering stuff properly). It was a real privilege to be surrounded by so many talented people; also, being able to design things that could make a huge impact really set my life in motion as a technologist before moving into more senior roles in the tech industry. Now, more than 20 years on from that fateful encounter with Visual Basic 5, I’m still doing exactly what I was doing at 14 – thinking about how I can make something and then willing it into existence. I blame it all on that Visual Basic book, which is still sitting on my bookshelf. More recently, however, I’ve begun to explore the world beyond software, and my inspiration for making things has turned towards what has been, rather than what is yet to come. I think this is important, because software as a medium is always a losing battle against entropy – as soon as you write something it exists for a fleeting moment before it starts its enviable decay towards obsolescence. As a reaction to this, I’ve started to take more of an interest in hardware, as it seems to have a longer shelf life. But, most importantly, I’ve rediscovered the physical beauty of hardware, and – to me – the more (seemingly) archaic the better! Recently, I’ve found myself becoming increasingly interested in early(ish) computing machines and hardware such as the PDP-8. This is not only because it’s beautiful, but because you can actually see what’s going on – the computing isn’t hidden away on a piece of silicon or in the compiler. This idea is exciting to me as a maker because it has reopened a whole new world and reignited my imagination for creating – leading to the genesis of my ARITH-MATIC project. ARITH-MATIC The story starts back in 2016 when I decided to make a serendipitous trip to the brilliant Museum of Computing in Swindon. This is a rather odd place, hidden away in an unassuming precinct in the town centre, packed full of vintage and retro computing devices from mechanical calculators to early personal computers and classic gaming consoles. I love it. After wandering around for a few hours, I was struck by two things: the aesthetic beauty of early mechanical calculators and the DIY spirit of the early micro-computer hobbyist kits – especially the Acorn System 1 (1979) and the Science of Cambridge Mk14 (1977). You can call it nostalgia, but there is something I love about these computational devices – how basic and tactile they are, unlike the shiny and polished devices we all carry in our pockets today. Inspired by the pioneering spirit of DIY electronics and the aesthetic beauty of mechanical calculators, I decided to design my own computational device. This would not only capture the archaic beauty of vintage computing, but also dissect the computational mechanisms that operate at the heart of these machines. 60 Fig.3. The 4-bit Cambrige-1 breadboard computer. Practical Electronics | February | 2020 wasn’t really a personal project anymore. I’d taught myself new EDA (electronic design automation) tools, built relationships with PCB manufacturers, opened accounts with electronic component suppliers, captured user-centred feedback from other makers and design engineers, grown a trusted network of freelance support, registered a domain name and was working from a studio. Whether I liked it or not I was actually a micro startup! At this point things got serious – I was ready to launch. This part, of course, is a whole other story in itself, but I’m pleased to say that – since that time – the S1-AU has found its way into the hands of many more individuals than I could have ever imagined. Enabling pragmatic makers, hobbyists, and enthusiasts to explore the guts of computing in a hands-on and practical way. And, that’s a really exciting prospect for a project that started life on a kitchen table. Back to me (Max) OK, back to me – Max – again. I have to say that I love the aesthetics of Richard’s work in the form of his black circuit boards combined with red LEDs and red tactile momentary pushbutton switches. I also appreciate the way he aligns all of his resistors the same way round, which is just the way I would do it (can you spell ‘obsessive compulsive’?). You can discover more about Richard’s kits at: https://arith-matic.com/ As I mentioned in my Cool Beans column in August 2019, I bounce back to England a couple of times a year to visit my dear old mom. On the last Friday before I return to America, a gaggle (an appropriate word to use as a collective noun in this case, I think) of my technogeek chums travel from around the country to congregate at my brother’s house. We spend the day showing off our latest and greatest creations while my mother provides appropriate ‘Ooh’ and ‘Aah’ sound effects, as and when required. Well, on my next visit, Richard has promised to join our merry throng. In addition to his temptingly tasty ARITH-MATIC boards, I’m hoping he will also dazzle us with his 4-bit breadboard computer, which he calls the Cambrige-1 (Fig.3.) As Richard says: ‘The Cambridge-1 is a 4-bit 7400-series-based CPU that features a 4-bit word size, blinkenlights-a-plenty, and some (slightly naughty) Arduinobased cheating to virtualise the control unit. It also contains an 8-bit data and address bus with some instruction set tricks to perform 8-bit operations as well. All of this at a whopping clock speed of 40Hz.’ Richard designed and built the Cambridge-1 to take to the 2019 Retro Computer Festival (http://bit.ly/34r1SYN), which was held the Museum of Computing in Cambridge. You can see a video of this little rascal running (the Cambridge-1, not Richard) on YouTube (http:// bit.ly/2OT2FuG). Also, you can read more about its creation on Richard’s website (http://bit.ly/34trxjA), and you can delve into the nitty-gritty details on Richard’s GitHub page (http://bit.ly/2OPU4cl). Well, that’s it for this Cool Beans column. I have so much to say, but I can almost feel the editor leaning over my shoulder and saying, ‘How many words?’. The problem is that, much like my dear old mum, the real trick is to get me to stop waffling. And so, until next time, have a good one! Cool bean Max Maxfield (Hawaiian shirt, on the right) is emperor of all he surveys at CliveMaxfield.com – the go-to site for the latest and greatest in technological geekdom. Comments or questions? Email Max at: max<at>CliveMaxfield.com Order direct from Electron Publishing GET T LATES HE T CO OF OU PY R TEACH -IN SE RIES AVAIL AB NOW! LE PRICE £8.99 (includes P&P to UK if ordered direct from us) EE FR -ROM CD ELECTRONICS TEACH-IN 9 £8.99 FROM THE PUBLISHERS OF GET TESTING! Electronic test equipment and measuring techniques, plus eight projects to build FREE CD-ROM TWO TEACH -INs FOR THE PRICE OF ONE • Multimeters and a multimeter checker • Oscilloscopes plus a scope calibrator • AC Millivoltmeters with a range extender • Digital measurements plus a logic probe • Frequency measurements and a signal generator • Component measurements plus a semiconductor junction tester PIC n’ Mix Including Practical Digital Signal Processing PLUS... YOUR GUIDE TO THE BBC MICROBIT Teach-In 9 Teach-In 9 – Get Testing! A LOW-COST ARM-BASED SINGLE-BOARD COMPUTER Get Testing Three Microchip PICkit 4 Debugger Guides Files for: PIC n’ Mix PLUS Teach-In 2 -Using PIC Microcontrollers. In PDF format This series of articles provides a broad-based introduction to choosing and using a wide range of test gear, how to get the best out of each item and the pitfalls to avoid. It provides hints and tips on using, and – just as importantly – interpreting the results that you get. The series deals with familiar test gear as well as equipment designed for more specialised applications. The articles have been designed to have the broadest possible appeal and are applicable to all branches of electronics. The series crosses the boundaries of analogue and digital electronics with applications that span the full range of electronics – from a single-stage transistor amplifier to the most sophisticated microcontroller system. There really is something for everyone! Each part includes a simple but useful practical test gear project that will build into a handy gadget that will either extend the features, ranges and usability of an existing item of test equipment or that will serve as a stand-alone instrument. We’ve kept the cost of these projects as low as possible, and most of them can be built for less than £10 (including components, enclosure and circuit board). © 2018 Wimborne Publishing Ltd. www.epemag.com Teach In 9 Cover.indd 1 01/08/2018 19:56 FREE COVER-MOUNTED CD-ROM On the free cover-mounted CD-ROM you will find the software for the PIC n’ Mix series of articles. Plus the full TeachIn 2 book – Using PIC Microcontrollers – A practical introduction – in PDF format. Also included are Microchip’s MPLAB ICD 4 In-Circuit Debugger User’s Guide; MPLAB PICkit 4 In-Circuit Debugger Quick Start Guide; and MPLAB PICkit4 Debugger User’s Guide. ORDER YOUR COPY TODAY JUST CALL 01202 880299 OR VISIT www.epemag.com Practical Electronics | February | 2020 61