Who has a sinclair scientific programmable?

[NetMage]

I had the Radio Shack EC-4001 that I used throughout high school - it was the envy of other students since I could program repetitive calculations. It is basically a Sinclair Cambridge Programmable.

[Harald]

I played a bit more with the Sinclair Scientific Programmable today and I found out what is happening. The accuracy for sin drops off very sharply beyond pi/2. Your to there it is fine, but 1.6 already yieldsa result that is completely meaningless (0.02986). Amazing how limited this calculator is.

Cheers,
Harald

[vaklaff]

(02-10-2022 01:09 PM)Harald Wrote:  I played a bit more with the Sinclair Scientific Programmable today and I found out what is happening. The accuracy for sin drops off very sharply beyond pi/2. Your to there it is fine, but 1.6 already yieldsa result that is completely meaningless (0.02986). Amazing how limited this calculator is.

See the operating instructions at https://www.wass.net/manuals/Sinclair%20...mmable.pdf. It’s by design and documented, so it’s a feature :-)

In case you can’t stand the poor machine, just send it to me, I think I can live with its limitations ;-)

[Harald]

(02-10-2022 06:41 PM)vaklaff Wrote:  See the operating instructions at https://www.wass.net/manuals/Sinclair%20...mmable.pdf. It’s by design and documented, so it’s a feature :-)

In case you can’t stand the poor machine, just send it to me, I think I can live with its limitations ;-)

Thank you! Having grown up on HP calculators it never occurred to me to read the manual for a fairly simple rpn calculator. Guess I was wrong

Thanks for the offer, I'll keep it in my collection
It won't get much use though, as that requires almost as much thought as using an algebraic calculator. And I prefere to think about the problem in hand, not the tool used to solve it...

[vaklaff]

(02-12-2022 09:22 PM)Harald Wrote:  Thanks for the offer, I'll keep it in my collection

Not that I expected anything else :-) I have the other programmable Sinclairs. Of course no real use for them - I too suspect they would be pain to use. However the Cambridge Programmable is among the most beautiful programmables I’ve seen. Big part of the magic is how small it is.

[Josef]

I recently bought two calculators, one of the first Sinclair Scientific calculators, unique because of its single-chip processor and a Sinclair Cambridge Programmable with 36 program steps. Both calculators have complete original packaging.

[Mike T.]

I actually brought one in early 1977 and I still have it (somewhere), but I replaced it with an HP31E as soon as I could afford one as it was so inaccurate, eventually I managed to save up enough to buy an HP33C which is still my favourite keystroke programmable.

[Josef]

True, Sinclair calculators did not excel in accuracy, by far, the most accurate were Texas Instruments calculators. Anyway, the white Sinclair calculators were amazingly small and beautiful.

[John Garza (3665)]

I agree. I have a few Sinclairs. We all get spoiled using HP or TI machines. Well... not 'spoiled'. Let's say accustomed to a higher standard. And stepping down is a difficult thing to do. OK for collecting, but not for actual use.

-J

[Josef]

I don't think anyone needs historical calculators anymore, but the history is wonderful and it's all about collecting. For example, the history of Sinclair is amazig, who today can invent and write firmware for a device in a few days?

The ROM storage in the calculator held only 320 instructions, just enough for basic arithmetic. How could they possibly squeeze any scientific functions into this chip?

Fortunately Clive Sinclair, head of Sinclair Radionics, had a secret weapon - programming whiz and math PhD Nigel Searle. In a few days in Texas, they came up with new algorithms and wrote the code for the world's first single-chip scientific calculator, somehow programming sine, cosine, tangent, arcsine, arccos, arctan, log, and exponentiation into the chip. The engineers at Texas Instruments were amazed.

[John Garza (3665)]

People have different desires. One may not 'need' something but desire it. And another may find the whole thing foolish. Freedom works that way.


And the cordic routines for math functions were known by those in the industry by then. Livermore BASIC in assembly had it and was freely available. Your tax dollars at work. Very smart guys nonetheless. But most were not starting from scratch.


... now if I can only convince Santa Claus I 'need' a Ferrari this year...

-J

[Josef]

Yes, I agree, lust is a terrible thing

[MinkLib]

The Sinclair Scientific, as widely reported, uses the TI TMS0805 chip, a very clever firmware job from Nigel Searle, reverse engineered by Ken Shirriff of Google in 2013.

But what chip does the Sinclair Cambridge Scientific use? About the same time (later in 1974?) as the Scientific and in the same case, but clearly a very different chip (3v supply instead of 6v, many extra features eg Pi, root x, natural logs).

[Johnh]

Was it this type? (pic below)

My Dad had one for his structural engineering firm. I remember working there for a summer. I already had the original Sinclair Scientific for school and id learnt about RPN. So I helped a couple of his guys work with it.

It was so stripped down! You only got 3 out of 6 basic trig functions (sin, cos and arctan), and only in radians.

So here's a puzzle for anyone for whom it's not trivially obvious: Try to remember how to get the other 3 trig functions (arcsin, arccos and tan)? And what are the fewest RPN keystrokes needed? (but at least, there was a memory plus square and square root keys).

One of the most basic daily calculations in any structures office is working out steel bar reinforcement for bending of a reinforced concrete beam. it boils down to solving a quadratic. I remember helping to write a program to do that on the Sinclair. But there were only 24 steps available! It was quicker than using tables, charts and slide rules

These days, this calc is nearly always done by proprietary software, as part of a much more extensive analysis of a whole structure. (But I think most young engineers now, would not know how to do this directly, and they were only shown it once at a lecture years ago which they didn't go to because it was easier just to download the notes, which they didn't understand)

But Dad probably should have ponied-up to get an HP.25 at least.

It was all a great learning experience for me and it locked RPN into my head until finally 40 years later, I got my first actual HP. By which time I didn't need it, i just wanted it.

[naddy]

(12-04-2024 09:20 PM)Johnh Wrote:  So here's a puzzle for anyone for whom it's not trivially obvious: Try to remember how to get the other 3 trig functions (arcsin, arccos and tan)?

I think \(\tan x = \frac{\sin x}{\cos x}\) is generally known, but why would you remember the arc functions? That's what GIECK or BRONSTEIN are for, or whatever formula collections engineers in other countries use(d before Wikipedia).

[AnnoyedOne]

(12-04-2024 03:07 PM)MinkLib Wrote:  But what chip does the Sinclair Cambridge Scientific use?

According to this page

http://www.vintagecalculators.com/html/c...nific.html

a General Instrument CF596.

A1

[AnnoyedOne]

(12-04-2024 09:20 PM)Johnh Wrote:  Was it this type?

http://www.vintagecalculators.com/html/s...prog_.html

A1

[AnnoyedOne]

(12-04-2024 09:20 PM)Johnh Wrote:  These days, this calc is nearly always done by proprietary software...

Not to worry. They can always pull out their "Smartphone" (or whatever) and ask ChatGPT for the answer.

Its not like a building could fall down and kill people

A1

[Ren]

(07-07-2018 08:59 AM)Thomas Klemm Wrote:  

Quote:So much pre-programmed power
So much memory

Wow, I didn't know that Hewlett-Packard also invented the Doge meme.
And that 38 years before it was cool.
Such hipster.

I didn't see a Hewlett Packard reference on the Wikipedia link.
(It wouldn't be the first time I missed the obvious!)
Ren
dona nobis pacem

[gentzel]

(12-05-2024 05:34 PM)Ren Wrote:  I didn't see a Hewlett Packard reference on the Wikipedia link.

You're replying to a 6 year old post. I'm sure the Wikipedia page has changed a lot since then.