Sinclair Cambridge 1970s Calculator Overview

[TheEPROM9]

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Thanks for your interesting video review.

All kudos to the engineers who were able to cram so much into such a tiny space; without SMD parts, it may look primitive to the Arduino Generation, but everything about this calculator, including the LED digit display, was cutting edge (most calculators where using vacuum tube displays). I note the PCB has the look of being designed by hand, with cut tape and sticky pad stencils. Now that's real layout skill.

I remember one of my father's engineering colleagues having one of these. From the vintage calculators website, I think it was a Cambridge model 2 or 3 in white. The Sinclair was not much of a threat to the engineers slide rule, but was way cool and a must have for all striving executives (and accounts).

http://www.vintagecalculators.com/html/sinclair1.html

As a vintage fan, I thought you might be interested in this Sinclair advert in an ancient Wireless World magazine from June 1977. Although rather lacking in functionality (even for that time), a wrist calculator was something from the Space Age. Respect to anyone who managed to solder one of these together.

For those "playing at home", £11 sterling in 1977 in today's money is ~ £70 ($132AUD/$90USD/80EURO). At time of posting, there's an uncompleted kit on ebay, collection only, for an eye watering £2,350! Compare this to the price of an apple watch.

[duak]

Ken Shirriff reverse engineered this thing: http://files.righto.com/calculator/sinclair_scientific_simulator.html   Smart people balancing trade offs to minimize resources.

About calculators: I wanted an hp 35 but couldn't afford it.  I saw the ad for the Sinclair scientific and thought seriously about buying one.  I bought a TI SR-50 from a friend who bought himself an hp 25.  I still have it and it still works.  I still have a few slide rules and they still work too, but the add/subtract function seems to have disappeared.

[IanB]

All kudos to the engineers who were able to cram so much into such a tiny space; without SMD parts, it may look primitive to the Arduino Generation, but everything about this calculator, including the LED digit display, was cutting edge (most calculators where using vacuum tube displays).

 

That 1970's Sinclair Cambridge calculator was from exactly the era when I and my teenage friends were in high school and owned such devices. At the time there were dozens of calculators on the market with any number of brand names--it was the "calculator wars" period when everyone was competing for market share.

Even back than the Sinclair calculators were crude, inconvenient and inaccurate when compared to the likes of Casio, Sharp, Commodore, Texas Instruments and many others.

I wish I still had my Casio calculator from 1976. The look and feel and build quality was fantastic, it was just silky smooth to operate with a feel of absolute solidity. It would pass Dave's "twist test" with ease.

[amspire]

I got the kit and used it in my first year at University.

Typical Sinclair kit - they had some segments reversed in the PCB layout, so you had to do a hack to make it work. Comparing the quality of the Sinclair to the HP21C I had the next year would be a joke - everything about the Sinclair was bad.

Looks like a few segments are missing now. It is just 5 digits resolution with a 2 digit exponent. You were luck to get about 0.1% accuracy, but that was enough for most purposes.

[tggzzz]

I got the kit and used it in my first year at University.

Typical Sinclair kit - they had some segments reversed in the PCB layout, so you had to do a hack to make it work. Comparing the quality of the Sinclair to the HP21C I had the next year would be a joke - everything about the Sinclair was bad.

That was true of everything Sinclair produced, starting in the mid 60s with his transistors and analogue amplifier kits.

Hence I refused to buy a Sinclair Scientific kit, and bought a complete working one. I still have it:

Looks like a few segments are missing now. It is just 5 digits resolution with a 2 digit exponent. You were luck to get about 0.1% accuracy, but that was enough for most purposes.

It was touted as a slide rule replacement, and just about met that spec.

Considering that everything was implemented in 320 instructions, it was an engineering feat.
http://files.righto.com/calculator/sinclair_scientific_simulator.html

[SiliconWizard]

I love Sinclair products - not for the end result per se, but how ingenious they always were. Most of them were crappy in various ways, but how much clever engineering went into them to make them so simple and cheap, that was something!

I have a Sinclair QL that I bought in non-working condition a few years ago, repaired it, and made all the recommended modifications from the service manual. It's in fully working condition now.

[duak]

Using the same minimalist white chiclet styling paradigm here's the Sinclair C5, an electrified recumbent trike from the mid 80's: https://en.wikipedia.org/wiki/Sinclair_C5  (Manufactured by Hoover - I wonder if it sucked?)  Seems to have gone over not at all well. The ingenuity that went into its design was necessary but not sufficient.

Nowadays we have its descendants; hordes of ruby-red 4 wheeled upright minimobiles piloted by well fed elders whipping around in stores and on city sidewalks at breakneck speeds.  Do you have them where you are?  I shouldn't be critical - I might need to get one myself some day soon.

[TheEPROM9]

Thanks for your interesting video review.

All kudos to the engineers who were able to cram so much into such a tiny space; without SMD parts, it may look primitive to the Arduino Generation, but everything about this calculator, including the LED digit display, was cutting edge (most calculators where using vacuum tube displays). I note the PCB has the look of being designed by hand, with cut tape and sticky pad stencils. Now that's real layout skill.

I remember one of my father's engineering colleagues having one of these. From the vintage calculators website, I think it was a Cambridge model 2 or 3 in white. The Sinclair was not much of a threat to the engineers slide rule, but was way cool and a must have for all striving executives (and accounts).

http://www.vintagecalculators.com/html/sinclair1.html

As a vintage fan, I thought you might be interested in this Sinclair advert in an ancient Wireless World magazine from June 1977. Although rather lacking in functionality (even for that time), a wrist calculator was something from the Space Age. Respect to anyone who managed to solder one of these together.

For those "playing at home", £11 sterling in 1977 in today's money is ~ £70 ($132AUD/$90USD/80EURO). At time of posting, there's an uncompleted kit on ebay, collection only, for an eye watering £2,350! Compare this to the price of an apple watch.

I love that website so much, this & old-computers.com provided so much entertainming & leaning dureing IT lessons back when I was at school. Taught me far more than the stupid coure schedual that was complte crap DIDA will bring sivers to the spines of anyone in my generation.

Really the better comparison over a inflation calculator would be the cost of simular calculators at the same time & lets be honest, Sinclair was kind of imposible to beat on price. I beleve mine is a MK3 but the first 4 are kind of exacly the same [basing it off the website]. So good luck knowing for sure. Some of Sinclairs kits & products go for stupid money these days.

[TheEPROM9]

Ken Shirriff reverse engineered this thing: http://files.righto.com/calculator/sinclair_scientific_simulator.html   Smart people balancing trade offs to minimize resources.

About calculators: I wanted an hp 35 but couldn't afford it.  I saw the ad for the Sinclair scientific and thought seriously about buying one.  I bought a TI SR-50 from a friend who bought himself an hp 25.  I still have it and it still works.  I still have a few slide rules and they still work too, but the add/subtract function seems to have disappeared.

Nice you have given me a good bit of bed time reading here. I do enjoy nitty gritty techy stuff.

[TheEPROM9]

I love Sinclair products - not for the end result per se, but how ingenious they always were. Most of them were crappy in various ways, but how much clever engineering went into them to make them so simple and cheap, that was something!

I have a Sinclair QL that I bought in non-working condition a few years ago, repaired it, and made all the recommended modifications from the service manual. It's in fully working condition now.

Oh yes Sinclair have some genius engineering while at other points it is pure crap. Glad Sinclair did not have access to the cheap shitty components of today or they would not have suvived 40 yeas +. Cudos getting hold of a QL, they go for crazy money even when in non-working condition. That was a machine that should have been in development for much longer & advatised as an upgrade to the Spectrum. History proved that aiming at the bussiness market was a kamakarzy move & thus Amstrad laped up the biggest player in the UK computer market. But that is why Sinclair was not a perticualy great business man. He was more of an ideas man.

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One of the most sought after calculators for mid-century collectors is the Sovereign. In all gold or silver it's a style icon: Absolute garbage as a calculator, but nothing says, I belong to the international Concorde jetset. Keep it in your Samsonite executive briefcase with your Raybans and copy of Mile High Magazine.

http://www.vintagecalculators.com/html/sovereign.html

The 'killer app' for calculators was the LCD; battery life went from weeks to almost years! I calculated the power consumption of my school Casio was around 100nA! How is that even possible, there's more current in a cup of hot lemon?

Sinclair was always a company by boffins for boffins [ Old British slang for geek if you're wondering]. Great on the innovation, rubbish on the delivery. Just try Dave's flex test on the original ZX80 home micro!

[TheEPROM9]

One of the most sought after calculators for mid-century collectors is the Sovereign. In all gold or silver it's a style icon: Absolute garbage as a calculator, but nothing says, I belong to the international Concorde jetset. Keep it in your Samsonite executive briefcase with your Raybans and copy of Mile High Magazine.

http://www.vintagecalculators.com/html/sovereign.html

The 'killer app' for calculators was the LCD; battery life went from weeks to almost years! I calculated the power consumption of my school Casio was around 100nA! How is that even possible, there's more current in a cup of hot lemon?

Sinclair was always a company by boffins for boffins [ Old British slang for geek if you're wondering]. Great on the innovation, rubbish on the delivery. Just try Dave's flex test on the original ZX80 home micro!

Oh god, these still sell for a pretty penney. The LCD changed everything, also the rush to make them as cheap as posible.

[rrinker]

 Definitely the LCD. I remember the first calculator we had at home, a Sharp LED. I think it took 5 AA batteries (it was an odd number, not the more common 2 or 4, and I'm pretty sure it was more than 3 - I think I still have one somewhere). 6 digit, 4-banger only. Ran through those batteries in a couple of hours. Quite expensive, too.

[Syntax Error]

Sorry guys, I thought of this today in the context of this thread.
A track I think that captures the zeitgeist of the pocket calculator revolution.
I'm sure you'll remember it first time round, if you're that old enough.

I am adding and subtracting
I'm controlling and composing
I'm the operator with my pocket calculator

Kraftwerk mit Taschenrechner (Pocket Calculator) :