Some Background

I’ve been collecting calculators for a while, and very recently I’ve been obsessed with the Voyager series of RPN calculators designed and manufactured by HP in the 80s.

While the series included several gems, like the HP 15C “Advanced Scientific Calculator”, and the HP 12C “Financial Calculator”, the most elusive model for me has always been the HP 16C; the “Computer Scientist” Calculator.

The 16C featured easy conversion between Hexadecimal, Decimal, Binary and Octal, as well as a very comprehensive set of bit-wise and logic operators and functions. As a true programmer’s tool, it allows the user to set the word size, scroll through multi-byte values, set the binary representation (1’s and 2’s complement as well as unsigned), perform simple floating point math, and write rudimentary programs.

I know that most programmers nowadays rarely require to work with data at bit level, but that’s the kind of programming I do. Not only when I work with micro-controllers but even when working on Big Data projects I’ve optimized processes using binary flags and masks. A lot of neat optimization techniques involve clever bit-level manipulation and low-level instructions.

The problem is, that unlike the 12C and the 15C that have received updates and new versions over the years, the 16C was discontinued in 1989, and currently second hand units are sold at exorbitant prices.

Now, I happened to get an HP 15C “Collector’s Edition” earlier this year, and quickly learned that there’s a rather usable hidden 16C “emulation” mode built into the device, that with a silicone overlay placed over its keyboard essentially turn the calculator into a 16C. Sort of. I will probably review that configuration later, but I was interested in having a standalone 16C that I could use on a daily basis without having to switch modes and put a rubber mask on my 15C.

That’s where the PX16C comes into picture.

The PX16C Kit

The PX16C is a soldering kit designed and sold by Alex Garza and it’s a beautifully well made piece of engineering that emulates the 16C in a very similar form factor.

I got the kit a week ago, and was ship to me very quickly. With the exception of some surprise DHL charges (Not the first time that it happens; That’s apparently how that company operates in my country) everything went smoothly.

I assembled the kit a couple of days after getting it, and I’m truly in love with the finished piece.

The PX16C comes with aluminum front and back plates that combine with a high-quality PCB and a screen into a very solid calculator that doesn’t feel too light or too heavy. It’s spot-on perfect.

The components all came carefully labeled and individually packaged, which is honestly great. The assembly instructions, while short, were more than enough to easily put the kit together.

I’ve used this calculator for several days now, and it’s a true delight. It’s definitely not a general purpose calculator for engineering (because just like the original HP 16C, it lacks several useful functions like log, sin, cos, etc), but it’s incredibly efficient for tasks like working with bit-masks, performing bit-wise and boolean operations, converting between numeric bases, using different binary complement modes, checking operations that interact with or depend on ALU flags, etc.

The tactile feel is a lot better than I expected from the standard buttons it uses. I mean, they are still a bit harder to press, but it’s surprisingly easy to get used to it. I assume that the aluminum cover helps with the operation of the keys, as tall buttons on their own would most likely wobble a bit when pressed, if they weren’t kept aligned and centered by their corresponding holes on the plate.

The screen is also very good; It’s extremely readable with a very nice font, and even has adjustable contrast via a special settings menu.

In terms of performance and features, from what I understand it runs at roughly twice the speed of the original HP16C, and it has some extras like a backlit display (with adjustable intensity and timeout) and a real-time clock; both great improvements over the original.

Overall I love the kit. I had a blast assembling it, and I’m very happy with how it works and how it feels. It’s a quality product made with love and care, and it fully scratched my itch for the 16C. I feel almost as happy as if I had purchased an actual HP 16C.

Alex also has several other kits from the same series, like an HP15C, and a “landscape” HP 41C, as well as an improved 41CX that features a 4-line stack, serial data transfer, internal memory for modules, etc.

I strongly recommend you to check out his work, and get one for yourself. Maybe I’ll end up getting a PX41CX eventually. The HP 41CX is another classic calculator that I don’t have in my collection, and Alex’s version seem to be every bit as cool as the original was and more.