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@octothorpe Wow, look at that hot HP-41C in her pocket!
I was just resoldering the connections to the LCD on mine trying to get it to work again. Now if I could just find an IR module on eBay for it.
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#rpn
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I have purchased a few new #electronic devices over time, ranging from vinyl record players (decades ago) to mobile phones (months ago). But none of them hold a candle to the excitement associated with gently unpacking a new #HP #RPN #calculator and cracking open that thick #programming manual.
My choices were never the best that money could buy, just the best that I was able to afford. Nevertheless, I recall vividly those moments, despite the passage of time.
Ta-da… from eBay to cleaned up + functional HP-35 #RPN calculator.
Even tho I was being careful I managed to drop those damn keys and the brass part of the power switch on the floor. There was no good way to restore plastichrome stripes so I sanded them off. I kind of like the minimal appearance.
Only things needed to make it work were rechargeable battery and fix the power switch.
May be urban legend but they named it HP-35 because it has 35 keys.
Acting on a mad impulse I bid on a lot of 3 vintage #RPN calculators. So I now have a new hobby - retro calculator restoration.
The HP-35 looks pretty rough. I can’t tell if it works. I’ll need a battery and charger. I plan on disassembly and thoroughly cleaning.
The HP-41 came with a quad memory module. I imagine the keypad internals have almost a half century of dust. Not sure if a tear down is worth it or not.
A formula for three-input exclusive OR using reverse Polish notation and only the NAND operator (spaces added for clarity):
C C AAB⊼⊼ BAB⊼⊼ ⊼ ⊼ ⊼ AAB⊼⊼ BAB⊼⊼ ⊼ C AAB⊼⊼ BAB⊼⊼ ⊼ ⊼ ⊼ ⊼
Symbols:
- A, B, C: push that input bit to stack.
- ⊼: pull two bits from stack; if they're both ones, push 0, otherwise push 1.
After the formula has been evaluated, the stack contains one bit: 1 if 1 or 3 of A, B and C were ones, otherwise 0.
#programming #math #rpn
"In today's video, we'll take a look at my grandfather's vintage HP-45 #calculator from 1973"—so he opens.
As an #EE who used #HP #RPN calculators for my whole career, that word, "grandfather", hit me hard.
youtu.be- YouTubeEnjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.
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@GhostOnTheHalfShell @dlakelan You betcha! Forth was my third programming language I ever learned. The first compiler I ever bought, for my Sinclair #ZXSpectrum. My main calculator on my phone is Free42, a HP 42S simulator. My physical one has gone the way of the dodo a couple of years ago. #RPN
Anyone else ever used a #rpn #calculator? I've been using a #SwissMicros DM15L and I LOVE it soooo much. One of the best calculators I've ever used.
Fighting Words
The #HP-15C (the original #Voyager Series) is, far and away, the best #engineering #RPN calculator, on balance: capability, size, shape, quality, durability, aesthetics.
OK, in a more civil tone, I realise my 15C is significantly less capable, in one way or another, than my 41CX, 32S, 28S, 48GX, 35s, Prime, ....
But why this irrational adoration?
Well, you'd know, if you're an engineer of a certain age who used calculators in your daily life.
eBayVintage Hewlett-Packard HP 15C Programmable Scientific Calculator 1980s TESTED | eBayTested and confirmed working Calculator only, no case or manual Ships with tracking and insurance
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Not using Cornu spirals, but cool to see PS in the wild.Replied to amen zwa, esq.
la .samflir. 
@AmenZwa Agreed! My #RPN #calculators are a HP-12C, DM16L, DM42 and HP Prime. I also use Free42 on my phone.
Fighting Words:
If you, like me, are still using #calculators in 2025, the only sensible input method for such ingenious devices is the equally ingenious Reverse-Polish Notation (#RPN), and the only acceptable manufacturer of such devices was the original Hewlett-Packard (HP).
Vintage #HP RPN all the way, baby! Ah well, OK; new #SwissMicros RPN, too.
#free42 une super calculatrice HP #rpn customisable ! Et quelle puissance !
Ça nous replonge dans les années d'autrefois !
#geek #calculators #linux
Using M5Cardputer as RPN Calculator #TindieBlog #M5Cardputer #RPN
https://blog.tindie.com/2025/01/using-m5cardputer-as-rpn-calculator/
Tindie Blog · Using M5Cardputer as RPN CalculatorIf you haven’t come across the M5Cardputer before don’t be fooled by the header image of this post. That keyboard is usually a full qwerty setup. The M5Cardputer is an ESP32-S3-powered …
In my career as an #ElectricalEngineer #EE over the past four decades, I've used several #HP #RPN #calculators (yes, only RPN). Of all those, my absolute favourites, in descending preference, are these:
• HP-15C
• HP-41CX
• HP-32S
• HP-35s
orpie(1) really is the only calculator I need. I appreciate grpn(1) and galculator(1) for supporting #RPN, but orpie(1) just wins for me.
GitHubGitHub - pelzlpj/orpie: Curses-based RPN calculatorCurses-based RPN calculator. Contribute to pelzlpj/orpie development by creating an account on GitHub.
It's the last day for my Black Friday sales - everything is 50% off today!
PCalc, my highly configurable scientific calculator with #RPN support, is only $4.99 USD.
iOS / iPadOS / watchOS / visionOS:
https://pcalc.com/store/pcalc
macOS:
https://pcalc.com/store/pcalcmac
Dice by PCalc, my 3D physics based #TTRPG dice app, is only $0.99 USD.
iOS / iPadOS / watchOS:
https://pcalc.com/store/dice
macOS:
https://pcalc.com/store/dicemac
Note that I actually say what my apps do, unlike my previous posts! #marketing
Who remembers #RPN (reverse Polish notation) in programmable #calculators?