Converting an HP 20B into a WP 34S

If you're into scientific calculators and miss, like me, the golden age of RPN machines, you're going to love this project. I'm talking about transforming a basic HP 20B business calculator into a WP 34S, arguably the most powerful RPN scientific pocket calculator ever created. 

I decided to write this post because while the conversion procedure is documented across various sources online, it's not always easy to find a straightforward, complete guide, especially when it comes to dealing with the infamous Pogo Pin cable issue. Back when HP sold these calculators, in fact, you could buy an official programming cable with a 6-pin Pogo Pin connector and erase/reset buttons. Today? Good luck finding one of those. They're practically extinct, which is a real problem because that cable is essential for flashing the new firmware.

In an age where everyone reaches for their phone or a computer when they need to calculate something, there's something deeply satisfying about having a dedicated, purpose-built tool that does one thing exceptionally well. The WP 34S embodies the best of HP's calculator legacy while pushing beyond what even HP achieved in their golden era.

This is a love letter to the calculators that got us through engineering school, that sat on engineers' desks for decades, that were passed down from mentor to student. But it's also something new: a community-driven project that proves open-source hardware and firmware hacking can create tools that rival or exceed commercial products.

The power of RPN

Reverse Polish Notation (RPN) stands out as one of the most efficient methods for mathematical calculations, especially for technical professionals and enthusiasts like me. Unlike algebraic entry, RPN allows users to enter operands and operators in a sequence that eliminates the need for parentheses and reduces keystrokes, a feature that makes it extremely fast and direct for complex computations and algorithms.​

If you add these premises to my more-than-two-decades long passion for retrocomputing, you can consciously enter my world!

Restoring a classic

I have always been fascinated by RPN, finding it surprisingly fast, intuitive, and more direct compared to the algebraic input methods of common calculators. The Reverse Polish Notation eliminates the need for parentheses and operator precedence considerations, allowing calculations to be entered sequentially and efficiently. Many users appreciate how RPN mirrors the manual process of solving problems, making the workflow smoother and less error-prone, especially for multi-step computations in technical and scientific contexts.

Bresser Maksutov 90/1250 telescope: my experience

It was during the lazy days of August vacation when I finally decided to fulfill a childhood dream of mine: owning a real telescope, even though an amateurish one. With some extra free time on my hands and that old sense of wonder about the stars still burning bright, I took the plunge and ordered the Bresser Maksutov 90mm with EQ3 mount.

These are my remarks, with some considerations on how I decided to publish them here...

Back in the US! In the city that never sleeps!

Well, it seems that blogging is definitely an outdated way to express oneself on the web nowadays. Additionally, I rarely write anything here anymore. Perhaps I feel that I have less and less interesting things to say (or to type). By the way, I am currently in New York City! 😊

VIC-20 The friendly computer

It’s been a long while since my last post on this blog. This boring era made of real time social things and dynamic digital networks full of contacts and followers (my optimal number of social interactions is far below the Dunbar’s number!) is eroding the time once devoted to write something more well-finished.

Anyway, a new post in the end, 5 years from my last one here. I will write again about retro-nerd-things and restorations I usually make during holidays, when I am far from everyday duties.

This year, also due to the home relocation we started months ago and which is still unfinished, I dedicated my time to fix and restore my first computer, yes the first one I have ever, ever had in my hands. All of my so long forgotten knowledge about it is deeply buried in the mist of my childhood memories, back to early 1984 if I am correct.

In that year Piaggio (my father then worked for them in a big bike dealership in Bologna) launched an ad campaign focused on a Commodore VIC-20 given away as a gift for customers purchasing a Vespa PX125. I can clearly remember those coloured boxes lying on the shelves, in the customer care area of BeMotor (the dealership’s name, today oriented in selling cars only).