OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

[Egan Ford]

http://files.righto.com/calculator/sinclair_scientific_simulator.html

[Steve Simpkin]

Amazing, fascinating, unbelievable and disturbing all in one product!

[Matt Agajanian]

I'll second that vote! Although, I must say the math genius who devised his even more inventive algorithms is certainly a very amazing mathenatician!

[Steve Simpkin]

I vividly remember really wanting a Sinclair LED Black Watch when it first appeared around 1975. Given its high failure rate, I guess it is good I didn't get one. I did buy and build a Sinclair Wrist Calculator kit around 1977. It was hard to build but it did work, even if it had mechanical problems.

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

I also remember being intrigued (because of its low cost) by the Sinclair ZX80 computer when it came out but I already had a much more capable Ohio Scientific C1P by then. Memories....

[Thomas Klemm]

I was hoping this would happen.

For those interested here's the Operating Instructions from Katie's manual collection for pre-LCD electronic calculators.

That's where you can also find the Assembly Instructions.

Kind regards

Thomas

PS: I like Milo.

[Katie Wasserman]

If Milo was still around I'm sure he'd say something like, "Woof!" (which roughly translates into I like you too).

[Thomas Klemm]

Inspired by the Sinclair Scientific I came up with this program for the WP-34s to calculate the logarithm:

LBL'LOG'

0

x<> Y

LBL 00

ENTER

SDR 002

-

INC Y

x>1?

GTO 00

DEC X

SDL 002

+

RCL/ 00

RTN

You have to initialize the register 00:

1

STO 00

XEQ'LOG'

STO 00

Afterwards you can use it:

SCI 4

5

XEQ'LOG'

6.9897 -1

I'm amazed by the accuracy of the results.

Cheers

Thomas

Edited: 2 Sept 2013, 11:21 p.m.