Tuesday, September 16, 2008

The iPhone HP 41C emulator (i41CX) - because sometimes madness must be honored

An obsessed madman has created a full emulation of a legendary scientific calculator ...

Advanced programmable and expandable RPN scientific calculator with virtual thermal printer/plotter suitable for a wide variety of scientific, engineering, mathematical, financial, and academic applications.

  • RPN logic with 4 element stack
  • Powerful rich set of numeric and mathematical functions
  • Time, calendar, alarm, and stopwatch functions
  • 12 character display with alphanumeric capability
  • User definable keyboard with support for overlays
  • Expandability: four module ports provide access to additional functions (e.g. matrix operations, programmer functions, equation solvers, etc.) beyond the standard built-in functions
  • Ability to download module files from the internet
  • Program features: automatic line numbering, labels, branching, subroutines, interactive alphanumeric input/output, loop operations, indirect addressing, flag operations, and synthetic operations...
Note the word "HP" does not appear anywhere on this page or on the screens. It's just an "scientific calculator". Nudge-nudge.

It cost me $8 to buy this. I might use the timer, and I might use the calculator every few weeks.

I bought it because sometimes glorious madness must be honored.

Update 12/23/09: There's a comprehensive (of course) FAQ on the AL Software site and a mini-manual. The original HP 41C manual is probably a bit hard to come buy, but, inevitably, another wonderfully insane geek has an online version and the i41CX manual points to PDF scans of the original manuals (252 pages!). Yes, and there's anHP41.org domain.

The only mystery remaining is who wrote this incredible application. The answer can be found on the HP-41 archive website emulation page. (Or you could just look at the author credits on the "mini manual").

I must add that I've recently scanned the "mini-manual" and "staggering" comes to mind. For example:
... Need to solve first- or second-order differential equations? Need to perform complex number operations and functions? Need to perform vector operations? Coordinate transformations? Number conversions and Boolean logic? Curve fitting? Solve time value of money problems? These are essentially the problems for which the HP-15C and HP-16C were developed. The Advantage Pac provides these capabilities to the HP-41CX. Thus, by loading the Advantage Pac and creating the appropriate key assignments, you can turn the i41CX+ into a virtual HP-15C or HP-16C!...
Oookaay. And let's not mention the GPS tools.


Anonymous said...

Gordon, thanks for leading me to the madman's cave. I will urge every person whon ever enjoyed the pleasure of owning and using the HP 41 masterpiece tool to support this insane project. My HP M-code programming days are long gone, but it sure will do me good making the odd average value calculation the good ol' RPN way :-) Support this man (assume somehow this is a He...) before HP decides to squeeze the lemon for a few more bucks (they've started with the HP 12/15/16!).

JGF said...

It's wonderful, isn't it? Sometimes madness is so extreme it becomes quite reasonable.

There's an FAQ from the author with a lot more detail on features:


I too assumed the developer was a guy -- but, yo know, there's no gender reference on the web site ...

Unknown said...

I had one HP41cx when I was in college and I love it. I read your i41cx app description and I bought the app immediately. Problem is I have no idea of how to upload or download programs from and to the internet as you describe. Please help.

Ruminator said...

Gordon, you posed this nearly ten-years ago. :o I recently fell into the HP-41C/V/X abyss, having caught the ancient handheld calculator disease. (I'm afraid I have a terminal case!)

When I was in university, the HP-41C was a suitable object of lust. I could not afford one, having already bought a TI-59 with the built-in card reader. But I was always an HP/RPN guy, having learned handhelds on a HP-35 and HP-45 when working as an engineering technician before heading back to university.

I owned a number of HP calculators over the years, they being my preference. The 48GX was my go-to unit for a couple of decades. But it's big and does not fit the hand well.

So... last year I bought my first HP-41CX and was hooked. Monte Dalrymple has an upgrade mainboard that will make the HP-41 50x faster and has almost all the modules on-board and soft-pluggable.

Three HP lovers assembled a firmware that can be uploaded to an HP-20b or HP-30b business calculator to produce the WP-34s. The 30b has a better keyboard and the process is not difficult.

I now use the HP-41CL (Monte's labor of love) and the WP-34s on a daily basis. These are my normal tools for quick calculations and estimates. Yes, I have computers for heavy numerical modeling, but I still prefer my hand calculators for routine tasks.

If you would like another rabbit hole, I also have Post Versalog 1460 and 1461 slide rules. One was from my university days and the other a replacement for one that got away. These are fascinating machines and mean that I could design even if we did not have access to computers.


The iPhone application lives on my phone, too. ;)