Ivan Vegvary wrote:


"jeff_wisnia" wrote in message
eonecommunications...

Ivan Vegvary wrote:

How many of you have taken this road? Those that have know what I'm
talking about.

Slide Rule, Marchant, Friden, Monroe, Curta, HP35, HP45, HP67, HP95,
Wang, IBM PC, DOS, IBM XT, $395 for 64K Ram card, VisiCald, Wordstar
modern day PCs and CAD programs.

The above are approximately in order.
Just for fun, I did spend some time with a Soroban (same as Abacus
minus one bead) and could multiply and divide just about as fast as
someone with a hand-crank Monroe.

I think the slide rule should still be taught. It sure gave use the
ability to estimate the order of magnitude of the answer. Ask a kid
today what 100 times 100 is. No clue. Something that's lost today.

Just an old fart reminiscing,

Ivan Vegvary


I took pretty much the same route and I've still got my Curta. But, my
first true digital computer was a single board uncased SYM, a 6502
processor machine with 2K of RAM and a hex display.

I used the Curta mostly for competing in sports car
"time-speed-distance" rallies, and cranked it automatically with a
single revolution motorized drive. I've still got the Curta (with a
hole in the center of it's bottom cover) and the drive/hundredth of a
mile odometer box. G

See center photo he

http://home.comcast.net/~jwisnia18/temp/rallying.html

Thanks for the mammaries,

Jeff


Jeff,
Looked at your website!! What an ingenious use of a Curta. Whatever
mad you think of this?

Ivan Vegvary

Well, the Curta was used by lots of rallyists back then, but they all
cranked them by hand and had to keep the cranking in pace with the
odometer indicated distance traveled. There were also some special
purpose circular slide rules made with scales appropriate to those
calculations and even books of tables which did the math for you.

So, it didn't eggsackly take Nobel prize grade thinking to let the
odometer's progress control the cranking of the Curta via a little PM dc
motor and worm drive reduction gearing. I stuck a one way roller clutch
in the connection between the motor drive and the Curta so I could still
crank it by hand without having to remove it from its location.

I got lucky because the odometer in that '55 Chrysler had a shaft in it
which rotated 100 times per mile so all I had to do was mount a little
cam on it which tripped a microswitch to trigger a single rotation of
the Curta. A latching relay and a cam tripped microswitch on the drive's
output shaft made the Curta make exactly one revolution each time the
odometer's microswitch cycled.

Enough already. G

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.