Search my site

Key Web Links
« Interview Part 3: Great Graticules! | Main | Interview Part 1: the control freak »
Wednesday
Mar142012

Interview Part 2: A voyage on Veroboard

Pinouts galore!

In Part 1 I explained how my interest in electronics probably stemmed from a boyhood fascination with instrumentation and controls inspired by TV shows such as Thunderbirds and Joe 90. As a 1970s teenager, Everyday Electronics (EE) was a “must read” for me. Practical Electronics (PE) was its grown-up sister magazine which contained some very daunting projects.

Other magazine titles included the very enthusiastic Practical Wireless with its heavily-stickered prototypes (not often related to radio!); the honest and traditional Radio & Electronics Constructor magazine standing firmly on safe territory; I felt ETI seemed a bit “wild” and rebellious, and Elektor offered a continental-style presentation and weird circuit diagrams. I guess you could say that PE and EE were dependable, wholesome pipe & slippers traditional British material, with some foreign renegades nipping at their heels.

If I saw one or two magazine circuits that I fancied the looks of, maybe I designed my own Veroboard layouts for them and experimented that way. Mid 70’s, we school chums struggled to create veroboard layouts or decipher transistor pinouts, and data sheets or catalogues with pinout diagrams were rare and highly prized. Wrong transistor connections – especially those terrible stumpy, angular Philips Lokfit transistors (BC148 etc) or TO-92 types were common and failure to understand pinouts caused a lot of disappointment in the early days. It would be some time before I could afford to buy the Towers’ International Transistor Selector databook though.

I noticed some interesting-looking reference and data books from my Tandy store (new in the UK in the 1970s), who co-branded National Semiconductor data books as “Radio Shack”. Hungry to learn, I lapped up every sentence of App. Notes published by National Semiconductor and I discovered some of National’s new linear devices, including the LM3909 flasher oscillator, LM3911 temperature sensor i.c. and LM3914 bargraph driver, and I couldn’t wait to dabble.

Even today I still use some low-voltage LED flashers based on the sorely missed National LM3909 1.3V flasher/ oscillator i.c. of 1975 vintage. I also got the Radio Shack/ National Semiconductor Voltage Regulator Handbook which was mostly too complicated, the RCA CMOS 4000  Manual and Texas Instruments 7400 TTL databook. Pinouts and logic circuits galore!

The original S-Dec solderless breadboard of the 1970s was used to test basic discrete circuits. © AWAs a 1970s lad I experimented on clunky S-Dec and T-Dec solderless breadboards (more Xmas gifts), and armed with a moving-coil multimeter from Tandy (a joint Xmas present from Dad and my brother) I started to dabble more and devise my own simple little circuits, making test measurements too.

The main thing is that, as a lad and youth, I was always very busy – I and many of my schoolfriends kept ourselves occupied with our hobbies, which apart from electronics also included cycling and wargaming.

I studied the American Civil War and had large Airfix armies of US and Confederate troopers, cavalry and artillery, and I built some detailed model townships and sceneries to stage battles too, often inspired by Western movies.  

... it was highly absorbing, wholesome fun that kept us off the streets and completely out of trouble. We didn’t have the time to have nothing to do.

The extra-thick sheets of card I needed for my model buildings came from frozen meal packaging that my Dad brought home from work, and I painted model buildings with leftover tins of emulsion paint. Terrains were constructed on Dad’s wallpapering table using polystyrene tiles cemented together and carved with a Proops Bros. polystyrene cutter. A local model shop sold lichen and scenery, and we used the school woodwork lab’s vacuum-former to mould our own scenery pieces (especially gun emplacements). We staged model WW2 wargames and many lads of my age had Airfix, Meccano or modelling skills, and it was highly absorbing, wholesome fun that kept us off the streets and completely out of trouble. We didn’t have the time to have nothing to do.

Ingenious beginnings

Ingenuity UnlimitedAfter starting to read EE in 1974 I also noticed Practical Electronics and a column called Ingenuity Unlimited, which featured readers' own circuits. My dog-eared files show that in March 1975 and barely 16 years old I submitted a very small idea, which I typed out using Mum's portable typewriter on some A5 paper from Woolworths. I would go on to dutifully type my letters and my little orders to mail-order suppliers on A5 the same way.

Much to my delight, Editor Fred Bennett accepted my idea for a simple oscillator/ metronome and I earned £5! It was published eight months later in the December 1975 issue of Practical Electronics, and some of my schoolteachers seemed quite chuffed at Winstanley A.’s burst of initiative.

A paragraph in print – I brimmed with pride. Little did I know that I would end up compiling the column 20-odd years later!

At the same time, I was roped in as the “electrician” and lighting operator for the annual school play, Saint Joan by George Bernard Shaw. The play was to be a last hurrah from the old grammar school before it was forced to change status. Winstanley of the Lower VIth would handle the lighting, audio and electrics. The setup needed an electrical switchboard that I remember helping to build from scratch (Home Radio of Mitcham supplied parts), and all sorts of emergency lighting (using 2V accumulators from the Physics lab and home made lamps, with tin cans as downlighters). Scene changes were plotted on a chart form that I designed using the school Banda machine.

The music score for Saint Joan was played on my brother’s Grundig TK141 reel-to-reel tape recorder (Isao Tomita’s Snowflakes Are Dancing and Pictures at an Exhibition, on the synth.) over a PA. There was terrible mains hum which a Physics teacher somehow cured by unhooking the earth(!). One night I was very gratified to see my backstage emergency lighting kick in when called upon.

Looking back, the whole school play was way too elaborate and over-ambitious. We used several dozen flood and spotlights (the usual effort used less than half a dozen), but the school gave us our head and we rocked to the sounds of Saint Joan of Arc in December 1975. I still have some of the Ashley brand 13A plugs left over from Saint Joan today.

Sidenote: I just bought both Tomita albums on Amazon today, and listening to them online made my hair stand up! More details of his work are at http://www.isaotomita.net/.

Feeling the power

Back to my hobby electronics. A d.c. power supply was a “must” for powering my experiments so before I was 18, I set about designing my own variable mains PSU. I bought everything piecemeal and had to be very resourceful because I had very little money.

The PSU could use an LM305H regulator and an interesting-sounding new device called the LM395K, a fully protected TO-3 power transistor with a gain of a million that I’d read about in Practical Electronics.

National Semiconductor kindly sent me some data sheets in the post. Farnell Components, National’s distributor in Leeds, sent a Pro Forma invoice for my little purchase. I saved up for the panel voltmeter which came from Laskys, a steel Bazelli-brand case came separately. Maybe Doram (the “Doorway to Amateur Electronics” offshoot of RS Components) supplied some RS parts too: I’d used 4mm leads and terminals in my Physics lessons so I chose those. I think I got the mains transformer for my birthday, when my Dad sent me along to the local TV shop to order it. Gradually the parts for my first variable power supply started to arrive as quickly as I could afford them.

Construction finally started and my Dad had to drill and punch the Bazelli steel instrument case for me, working between us on his garage workbench (still in use today) as best we could.  It was hard work (being an all-steel box) and I learned lots of practical skills as we went along – how to design and mark out a box, how to centre-punch, drill steel using high-speed twist drills, how to file down and deburr holes, and I was already skilled at using Letraset for labelling.

I soldered the circuit on some stripboard, learned about TO-3 power transistor mounting kits and discovered (much later) that the d.c. voltmeter accuracy was skewed by the steel chassis! Looking back, my first mains power supply was extremely ambitious work for a kid’s project but I was determined to make it work, and it went on to power lots of early circuits. A back-e.m.f. pulse zapped the expensive LM395K output device when I was playing with a relay or solenoid one day.

Having tasted early success in PE Ingenuity Unlimited, then, I submitted a second item, which was my Bench PSU based on the National Semiconductor LM305H/ LM395K design. It was accepted and appeared in the March 1977 issue of Practical Electronics. This time I earned twice as much - £10!

Shortly after, I received a reader's letter (Edinburgh School of Veterinary Medicine I think) describing the new LM317 variable three-terminal regulators which promised to simplify the whole design process. I was very intrigued by the LM317K (TO-3) version of this new device and earmarked it for the near future.

I continued to learn by reading magazine articles, studying circuit diagrams and looking at photos of prototypes to fuel the inspiration for more projects. By now I’d just left school and started my first job. I’d not managed to join the RAF as an Air Electronics Operator (AEO) on Nimrods, my first career choice. I was a bit too young and competition for aircrew posts was intense, and after failing a horrid interview in York with Midland Bank, my school steered me towards the accountancy profession instead and I started work locally as a trainee accountant, of all things.

As a young clerk I toiled over final accounts and tax computations. For a desk, I was seated on an old wooden chair, behind a small old kitchen table made of tongue & groove. My pen often stabbed holes through the paper when it hit gaps in the tongue & groove beneath. The firm’s formidable Senior partner had the firm's only calculator, so everything else was calculated by hand, and I could add up (or “cast”) columns of figures mentally extremely rapidly. I learned that calculators dulled the brain. We jotted our notes on offcuts of paper scrounged from a local printers: I remember that the Senior partner’s handwriting was absolutely tiny, microscopic, as befitted the parsimonious thriftiness of a Chartered accountant.

No accounting for my hobby

The 723 regulator mystified me a bit at the time. Bring on the National LM317...My early working life was a baptism of fire. Still, I was given training and I had a rock-solid foundation in handling different types of business, accounting, book-keeping and tax which I still use today.  While studying for exams at college on day-release and nightschool, I somehow managed to maintain my interest in amateur electronics. One or two home-spun ideas didn’t quite work but I don't think I had any real disasters, apart from a cassette player PSU that I'd built for a fellow clerk. I hoped my 723 regulator circuit would allow him to use his cassette in his car, but his vehicle had a positive earth and when I powered it up, my circuit blew up with a resounding “crack”! However I can’t think of any project that failed to work (eventually anyway).

Having got the hang of some electronics construction basics, my project ideas started to come thick and fast in the late 1970's. I often had a notepad at home to sketch out ideas or copy notes from reference books from the local library. Often I would have to thumb through a textbook or magazine article in order to figure out some design aspect or other, or I would run my own tests to find out what happens. My Physics schooling had taught me to enquire methodically.

Again, I didn’t build projects from magazines but devised my own ideas instead. Maybe the prospect of magazine projects not working frightened me a bit. Gradually as I became surer of myself, I reckoned that I could probably match at least some of the published material that was printed in Everyday Electronics at that time. Although I didn’t have any formal training and wasn’t the best designer in town, by now I was confident with construction and assembly and I enjoyed building projects to as professional a finish as possible. Equally importantly, I enjoyed writing good factual English with clarity, and I could see how the technical elements of a good constructional article would need to be composed.

First "constructional" article

 April 1978 Everyday Electronics featuring my first ever project, the Mains Delay Switch

It was September 1977 when, still 18 years old, I drafted my first full constructional article and submitted it to Everyday Electronics. It was a 555-based mains relay device with manual override, offering a delay of up to an hour. Editor Fred Bennett wrote back saying that it was a well-prepared article which they were happy to accept.  The Mains Delay Switch appeared in the April 1978 issue and I earned the astonishing amount of £160 – equivalent to six week's wages at the time. 

You can download a PDF of the 1978 article from here and you can revisit the original prototype with colour photos and notes here.

IPC Magazines did me proud, featuring the prototype on the cover (I’d used a rakish sloping orange console as a housing) and it was a long-ish constructional article.  I later used the prototype to turn off the bedroom sidelight after a delay (which annoyed my brother).

So there I was, now building my own control panels, not the ‘pretend’ ones on upturned cardboard boxes from my childhood TV, but proper-looking things on punched aluminium panels with smart knobs and lamps, all labelled properly using Letraset.

I followed up with the Auto Nightlight in July 1978 EE, which was an ORP12 photocell-triggered op.amp that powered a 12V bulb in an aerosol cap diffuser. It looked odd in a steel instrument box but my work earned me an amazing £150.

You can fetch the Auto Nightlight PDF from here. I found the original prototype which you can explore here.

Then I offered the magazine a small list of ideas that was going through my ever-active mind – Everyday Electronics wanted them all.

The October 1978 issue carried my simple Fuse Checker when I reached 20 years old, a simple LED go-no-go indicator of a blown fuse. The original article is here and my prototype notes are here.

Next came my Water Level Alert, a simple 555 oscillator powered through a transistor switch. It was built in a new style of orange Bimbox (Boss Industrial Mouldings) which offered a stylish alternative to mundane white plastic or aluminium folded boxes that were popular at the time. Stripboard could be held vertically in slots with no hardware needed.

You can download the original article and my prototype notes.

The Water Level Alert's orange box duly appeared on the front cover of December 1978 EE, and this style of construction would frequently be repeated later down the line. Editor Fred Bennett mentioned that my Water Level Alert was also displayed on the magazine’s stand at the 1978 Breadboard Exhibition. I was barely 20 years old and I burst with pride. Such was the keen interest in hobby electronics in those days that entire exhibitions were held, dedicated to DIY electronics. 

Write on!

Communications with the magazine were handled in writing and Editor Fred Bennett always wrote polite but formal letters, you know, proper correspondence that I hadn’t really experienced before then. For me it was an object lesson in writing classical English correspondence. Dear Sir, Thank you for yours of 21st. inst., etc., Yours faithfully, and it was all typed manually.

Correspondence was slow and laborious, creating a mountain of paperwork and carbon copies. IPC Magazines would write acknowledging receipt of a manuscript; write again to accept (or sometimes reject) it; write again asking to borrow the prototype for photography, and write again confirming its receipt; write again with a “pink” (as they are still called today) invoice for me to sign and return; write again with a cheque; and write again returning the prototype: 6 or 7 letters each time. Today this volume of work would seem completely crazy given the advent of Email.

In mid 1978, when Fred Bennett wrote back accepting my Water Level Alert project he also asked if I would be interested in developing some simple, single-transistor designs to be built on a small piece of stripboard, suitable for complete beginners to tackle. They may also be interested in i.c. projects too, he added.  I wrote back : “Sure!” and proceeded to outline some Simple Transistor Designs (the series’ working title). These would eventually appear in EE as “Uniboards”.  Fred sent me some sample stripboards, 2½” x 1” (the “Free with EE” size). 

Fred sometimes reminded me about this when he wrote, and it was clear that they were keen to see these simple projects soon. Looking back at the actual publishing dates though, I see how my projects appeared sporadically and not in a series format as I’d hoped. I recall being disappointed and frustrated by the publishing delays after all that fuss. Later this would become symptomatic of the turmoil that the electronics magazines faced underneath the surface.

In Part 3, I’ll describe more projects and developments, including the popular EE Uniboards and other memorable ones that were highly popular at the time. I'll also rediscover the actual prototypes and upload details of them.