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HP-35 and Python

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VE1DX
(@ve1dx)
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This is Python-related and has some nostalgia.  I hope this is an OK Forum to post it.  Does anyone remember these?

IMG 8401

I bought mine in 1972, 50 years ago, and it still works.  Replaced the slide rule under it in subsequent years of university.  This was $425 CDN in September 1972.  That was every cent I made doing pick and shovel work that summer. Anyhow, it still works. The battery pack is shot, but I found a replacement on eBay (it's still "in the mail.")

I have a Python 3.7 (or higher) emulation program almost finished for it.  It works well, except I want to try to map the HP-35 keys to a Linux and/or Mac QWERTY keyboard.  That part is giving me a lot of trouble, but I think the getkey library will save the day.  Python's input() is limited.

When it's finished, I'll post the GitHub link.

- Paul VE1DX


   
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VE1DX
(@ve1dx)
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Such as it is.  My first "toe in the water" with Python programming:

https://github.com/ve1dx/hp-35

I have tested it on Debian-11 (on a Pi 4) and Ubuntu 22.04 with an Intel CPU.  It seems to work fine on those.

- Paul VE1DX


   
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Ron
 Ron
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@ve1dx I used to have a very fancy slide rule in college, log log hyperbolic something in a fancy leather case, about a foot or more long, but it was stolen. I never needed or used an electronic device like your HP, due to working as an industrial electrician followed by the start of my IBM career in 1966 for 15 years then the PC revolution hit and I used Multiplan. Nonetheless I am looking forward to your emulation program, keep us informed.

"Don't tell people how to do things. Tell them what to do and let them surprise you with their results.” - G.S. Patton, Gen. USA
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon


   
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VE1DX
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Every operating system I know of comes with a built-in calculator these days.  Smartphones as well.  This program was more of a chance to re-live my days in 1972-1973 and learn a bit of Python.  I don't think anyone will use it in favour of the Linux/Mac/Microsoft built-in GUI ones. But they can if they wish.

It seems to emulate that old calculator well, which was the goal.  I wasn't trying to build a better mousetrap! 🙂


   
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MrRemedy
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Wow.  I was a collector of the slide rules...  Have you ever seen the circular design of slide rules?

 

-d


   
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Ron
 Ron
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@mrremedy I saw a few engineers using circular slide rules. I think the reason they used them was they would easily fit in a shirt pocket.

"Don't tell people how to do things. Tell them what to do and let them surprise you with their results.” - G.S. Patton, Gen. USA
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon


   
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MrRemedy
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@zander Mine were so huge, they would not.  They used them as more revolutions increase your calculations.  You just have to remember how many time you revolved the disk to get the higher numbers.

-d


   
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Inst-Tech
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Posted by: @mrremedy

@zander Mine were so huge, they would not.  They used them as more revolutions increase your calculations.  You just have to remember how many time you revolved the disk to get the higher numbers.

Hi @Zander and @mrremedy,

Was reading your post and made me remember those days when we still had to use slide rules, all types..

I my industrial background we used circular ones because that what the Control valve vendors supplied us with...lol

Before software Control valve sizing programs were available, that's how we done it!.. I still have my slide rule from my tech school days (circa 1973) Taught my grandson how to use it when he was 10, he's now 25..and forgot everything about it..hahaha   We're the last of the Mohawks as they say..

The only thing more fun to troubleshoot than a electric relay panel was a pneumatic one for a control system on a boiler or paper machine...lol

Pnumatic control panel

 

 

LouisR


   
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Ron
 Ron
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@inst-tech Pneumatic is a new one on me. Is that a can of WD40 lower left?

"Don't tell people how to do things. Tell them what to do and let them surprise you with their results.” - G.S. Patton, Gen. USA
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon


   
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Inst-Tech
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Posted by: @zander

@inst-tech Pneumatic is a new one on me. Is that a can of WD40 lower left?

Hi @zander..nope..all those pneumatic relays and controllers had to be de-greased so they wouldn't stick, so it's probably a can of solvent or de-greaser.. also the air had to be fairly moisture free, so the air had a dew point of > -20 deg F, mostly we kept it around -40 deg F dew point. When I first started out in Instrumentation, most industrial controls were all pneumatic, or electric relays..first time I saw an electronic  2-wire instrument and digital control system was in 1975 .. before that electrical instrumentation was 4-wire, 2 wires for 120 volt supply, and the other 2 wire (output) were  0-10 volt dc , later 4-20 mA into a 250 ohm .1%  resistor to develop 1 to 5 volt dc to the ADC for the digital computers.

Most instruments of the pneumatic type were a standard 3-15 psi output, into recorder, or controllers with 3-15 psi inputs and outputs..you had to a mechanic with the skill set of a watch repair man...because the parts and screws were so tiny...lol

If you want to see examples of pneumatic relays and instrumentation..just google pneumatic relay photo..

regards,

LouisR

 

LouisR


   
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MrRemedy
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@inst-tech In regards to slide rules...   They never require batteris, an internet connection.  They're always on.  :O

There are a number of Online Slide-rule simulators out there.  I have several of the Pickett line.  If you've checked eBay, they've become pretty valuable!

Found:  https://sites.google.com/site/bobssliderulesite/sliderule-software

OK.  Now I've gone off track.   Why are we talking about slide-rules on DBW?  Because it culminates a great sense of coterie. 

-d

-d


   
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Ron
 Ron
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@mrremedy I had a great slide rule, but now I have different (better?) tools. It's like VOM's, do you really want to give up your auto sensing, auto ranging VOM that cost <$50 for a manual and easily broken >$100 analogue meter?

"Don't tell people how to do things. Tell them what to do and let them surprise you with their results.” - G.S. Patton, Gen. USA
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon


   
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MrRemedy
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@zander Nope.  I traded in both of my Flukes for a Siglent Bench and Greenlee DMM meter.  I, at one time, had a Simpson VOM, but regrettably lost it in a family trust dispute.

-d


   
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Will
 Will
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@mrremedy 

I finally found mine. The numbers are still clear but the slide doesn't move easily so I probably need to take it apart and clean it ...

IMG 2609

 

Experience is what you get when you don't get what you want.


   
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Ron
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@mrremedy I almost inherited a Simpson, but now just as glad I didn't, I am a full time RVer at the moment and that Simpson meter movement would have been destroyed by riding in my basement. I have purchased 5 or 6 digital meters, and my current digital is very handy, auto sensing (V vs R), auto ranging, auto turn off with warning, a lot smaller, and can take a beating and keep on ticking.

"Don't tell people how to do things. Tell them what to do and let them surprise you with their results.” - G.S. Patton, Gen. USA
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon


   
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