
Free42: An HP-42S Calculator Simulator (2005) - _83te
https://github.com/thomasokken/free42
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tass
SwissMicros make nice clones of classic HP calculators. They sell an HP-42s
clone which runs Free42:

[https://www.swissmicros.com/dm42.php](https://www.swissmicros.com/dm42.php)

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goatinaboat
It’s a beautiful machine, superb build quality, as good as genuine HP pre-
Fiorina. If anyone is considering one, you will not be disappointed.

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tass
I bought the DM15L only a couple of months before the 42 was released and it's
built really well.

I don't have the HP to compare the button feel to so it may not be exact (and
there are differences in looks) but it's nicer than any other calculator I've
seen available to buy today.

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goatinaboat
There’s less travel in the Swissmicros keyswitches, that’s the main
difference. But it’s still massively more tactile than a touchscreen.

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joezydeco
I’ve been using the iOS version for longer than I remember. It lets me leave
my actual 42S at home where it’s safe and sound...

[https://apps.apple.com/us/app/free42/id337692629](https://apps.apple.com/us/app/free42/id337692629)

There's also an Android version:

[https://play.google.com/store/apps/details?id=com.thomasokke...](https://play.google.com/store/apps/details?id=com.thomasokken.free42&hl=en_US)

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zinclozenge
I still have my HP48G I bought in 2000 for college calculus. Introduced me to
reverse polish notation, loved the tactile feedback from the keys. I bought a
simulator for it on my phone.

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jsilence
Lately got my HP48s stolen when our office was raided by burglars. Had not
used it for quite a while but loathing losing the university studying memories
attached to it.

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jaclaz
Why (2005)?

The tool on github (and the homesite):

[https://thomasokken.com/free42/](https://thomasokken.com/free42/)

have been updated recently (2019).

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thomasokken
I started the project in 2004, and the commit history goes back to 2005, but
it's only been on GitHub for a couple of weeks.

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joezydeco
THANK YOU THANK YOU THANK YOU for maintaining this project, Thomas!

I’m sure it’s a hard effort to keep it running on so many platforms at once
but it’s a incredible piece of work.

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antod
The calculator that got me through engineering school in the early 90s.
Excellent little machine, but I was a bit jealous of the guy with a 48S.

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GlenTheMachine
You shouldn’t be. Today, I use an HP-42 as my desk calculator. It is a
considerably better tool for that job than my HP-48, which is significant
overkill. And if I have a problem for which the HP-48 might be the better
tool, in actual fact Matlab is the right tool for that job.

The HP-42s hits the sweet spot for scientific calculators in the era of
powerful computers. It is small enough and its interface is fast enough that
it is still faster to do calculations on it than it is to fire up a calculator
app.

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criddell
I used an HP-28s to get through school. Like all of them, the battery door
broke and now it's basically junk.

My desktop calculator these days is an HP-35S which is to find and
inexpensive. I've been thinking about a Swiss Micro clone of the HP-15C but
it's hard for me to justify the purchase.

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tzs
If you do a lot of calculations while reading paper books, or while writing in
a lab notebook or on a clipboard, the HP-15C makes a great calculator.

The landscape form factor, in my experience, is less likely to get in the way
of my book or paper than a portrait form factor. Probably because we write
left to write then top to bottom, and read the same way, and so a landscape
form factor overlaps fewer lines than the same area in portrait form factor.

A phone calculator in landscape mode is not as good for a couple reasons.
First, phones tend to turn off when idle for a bit. It gets annoying to have
to keep unlocking the thing.

Second, without physical buttons it is a lot harder to operate without
looking.

This later problem could be addressed if you made a physical overlay that you
could put over you phone screen, which covers the key section of the phone
calculator, and has a hole over each key. Make the overlay thick enough that
it is easy to feel where the holes are. That should provide enough feedback to
let you use the calculator without looking.

(Fancier would be to make an overlay that actually has physical buttons. Make
the buttons out of something that conducts touch, so that when you press it
the button touches the screen).

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GlenTheMachine
I have my wife’s HP-15C that she had in grad school. Unfortunately it had an
accident and got doused in liquid soap. It still works, but drains the
batteries in just a day or two, and I’ve never figured out how to fix it.

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dwt204
Thank you. I will check it out.

