Using Free42

Free42 is a free, open source emulator of the HP 42s calculator that can be downloaded and used on an iPhone, Android, and Windows, Mac, or Linux computer. It is WONDERFUL! Once you get used to RPN notation it becomes an extension to your brain! This video is an introduction to the calculator for my physics and math courses for homeschoolers (available for digital download at mathwithoutborders.com).
BTW, you don't need to be a homeschooler to teach yourself the parts of high school math (Algebra through Calculus) and physics you missed out on because you were a distracted teenager at the time!

[@martinstabb7059]

I’ve been an HP user since 1983 but my last calculator is this Free42 calculator. It’s fantastic and so much quicker than any of the physical calculators for complex programs.

[@Pepsiphopia]

Got an SwissMicro DM42 for my CNC-course and had no clue how to use it. Thanks to this video I can add numbers together xD

[@skysurfer5cva]

The SwissMicros website has links to the HP-42S manuals (Owners Manual and Programming Examples and Techniques) and other documentations. The links are found on this page: www.swissmicros.com/technical#docs-dm42 A google search for "manual for hp42s calculator" will also find these manuals as well as a very nice "alternative manual" written by Jose Stapasson. The latter manual can be found on Thomas Okken's website (Okken wrote Free42) here thomasokken.com/free42/42s.pdf. There is also a lot of information at the HP Museum website (www.hpmuseum.org/) run by David Hicks. I have been using an HP42S since 1989, Free42 for at least a decade, and a SwissMicros DM42 (based on Free42) since 2017.

[@jonathanschmidt4985]

Love 42 app, was an Army Engineer Surveyor in the 90's and picked it from their, used it for surveying ever since, easy to program, all the functions you need, and these days have it on all my computers and smart phones ready on hand. Many of you say the instrument or gnss cpu does it all but it is piece of mind to be able to check or change things while you are there. Special thanks to Thomas Okken and the free apps he has, well done mate.

[@Crazytesseract]

To avoid any confusion, you could use the × or * symbol for multiplication, instead of a centre dot. Another thing: the 42S operates in the complex field by default. You can take square roots, roots, logs, trigonometric func, hyp etc. if complex numbers, which most other physical calculators cannot.

[@ZedAlfa.]

I loved my HP 42S

[@zerobeat2020]

MathWithoutBorders, I have used RPN calculators for a long time (I bought my first RPN calculator in 1983, an HP-11C) and for very complex calculations, but never once ran out of stack space as you suggest you could. Providing you always work from inside the parentheses outwards and make use of x and y swapping and stack rolling, you find that 4 registers (and perhaps last x, although I use that rarely) is all you ever need! I also find that having a bigger stack doesn't necessarily make things easier. Granted you can be a bit more careless with your calculations, but this in turn increases the risk of making mistakes. Like so many things in live, RPN needs a bit of practice but as you say yourself, once you learn RPN you don't really want to go back!

[@codycbradio]

I love my DM42 which uses Free42. I love the fact that it has 34 digit precision. And plus the battery life on it is great. So you don't have to worry about programming a complex program and having your cell phone battery die. Plus the fact you can save the programs from the DM42 to the Free42 Applications.

[@davidschandler48]

My problem with the DM42 is the flakiness of the keys. I can't get data entered reliably. I have one but don't use it. This is a fatal flaw, for me. Do you have the same problem?

[@codycbradio]

@@davidschandler48 No. The keyboard on mine seems to work just fine. It may be because I got a later version.

[@zerobeat2020]

@@davidschandler48 mine is great too, never an issue with keying in things on the DM42. My only gripe with this calculator is the rubber feet, which makes the calculator wobble a bit (easily fixable) and the enter key has two micro switches, which means that it feels a bit odd when you press it, although never seems to cause an issue. Neither of these issues take away from the fact that the DM42 is hands down the best RPN calculator currently available on the market.

[@MarcelHuguenin]

I am using it for several months now on Mac, Windows, Linux and iPhone and I love it.

[@7ismersenne]

I share the enthusiasm of the previous posters for the Free42 (HP42s simulator). It is a beautiful little program. I have it on my Linux Mint 19.3 laptop and on my Samsung a21s mobile. I love it. And long live RPN. Free42 is a coding tour de force by Thomas Sokken, many thanks, mate.

[@kahuna1247]

Ah... HP42s brings me back to my university and graduate days, now a long time ago!

[@Mario_b2921a3f]

This is pure gold. Thanks a lot, sir!

[@petercook3911]

Great tutorial on RPN, nice and clear, thanks!

[@mgmartin51]

There's a great line in the movie "Down Periscope", where the engineer shouts "DBF!" which means "Diesel boats forever!" I was thinking "RPNF!" It's too bad HP dropped all of there great calculators (the HP42, the 48g, etc.). I know, you're thinking "OK, Boomer!" Did I mention I love slide rules too?

[@richardbailey2001]

I appreciate how good this calculator is, would you be able to find any angle using like 3π/4 ? Couldn't find a way to get correct answer.

[@grshorwich]

Just to be more accurate, Free42 is not an emulator, it is a simulator. An emulator will emulate the hardware of the original platform and run the original device's ROM. Emu42, for example, does this. Free42 does not. It is a simulator that behaves like the original in every way but by using all original code by Thomas Okken. Not a single line of HP code is in Free42.

[@Crazytesseract]

Thanks for this useful information.

[@7ismersenne]

good point. As I mention above Thomas Sokken has done a brilliant and original job coding up Free42

[@4thesakeofitname]

Well, that's a bit jargon dependent, at least for a digital "calculator"; as long as all user accessible features, functions, including variables, registers, program memory etc were included in the "simulator", then it's virtually indistinguishable from an emulator, unless there are numerical differences in the computation results. Because a simulation, in my jargon, is a sufficiently accurate approximation to a physical system's behaviour by means of a simplified model of it. So do you mean, free42 outputs "slightly" different results than the original hardware (or its emu42 emulator) ?

[@dhy5342]

You might want to take a look at Plus42 which is Free42 on steroids from the same programmer. It's equivalent to the DM42.

[@theodoresweger4948]

I love mt HP35s

[@bitsnbytes7514]

I'd love to see a true pocket LISP machine -- I mean true LISP (or Scheme), not just RPL like on the HP-48. The DM42 might be repurposed for that since you can flash your own firmware on it. Sounds like a lot of work though.

[@jakubkolcar6789]

What you mean by lisp machine?

[@MattMcIrvin]

Casio actually made a pocket Lisp computer in 1989, the Casio AI-1000. I think it was only sold in Japan.

[@bitsnbytes7514]

@@MattMcIrvin I'd never heard about that before. How interesting ! Thank you.

[@MattMcIrvin]

@@bitsnbytes7514 I think it is one of the calculators emulated by the commercial PockEmul project, but I have not tried that.

[@georgwrede7715]

The skin you are using has a poor contrast in the display. Instead you might want to use Georgs-HP2, which has a lighter background and darker digits. -- For your computer, it has also the keyboard key shortcuts visible. (Regards, the Georg )

[@michaelbaker5070]

Whare can I get the calc98?

[@williamweatherall8333]

I'm getting 0.0266 @14:39 on both my calculators. Is there something I'm missing?

[@holgerschnarre2052]

first means 3*5, not 3.5

[@IO23777]

"I've cleared out the calculator" How ? Mine looks like a dog's dinner how to reset it?

[@davidschandler48]

One way is to type in a zero and hit enter 3 times. This wipes out the stack. A more formal approach is to use the 2nd function, CLEAR key. All of that is for aesthetics, however. Garbage on the stack will not affect your current calculation. (It might affect your brain, however!)

[@IO23777]

@@davidschandler48 Thank You

[@cosicave5179]

Disappointing. I was hoping this video would not be so focussed upon the basics of RPN, and be an evaluation of the calculator, using some of the far more advanced features it is capable of. And why not even touch on the option to choose an unlimited stack instead of just TZXY? And why not mention that it can save any number of 'State' files for instant reversion to how it was set up before? - And there was no mention whatsoever that this calculator's strongest point is that it's fully programmable!

[@MathWithoutBorders]

Go for it. My audience has been high school students taking my physics and math courses. I am highlighting the basic features they will need. A more thorough exposition would be good to have.