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Thanks for the kind words. Regarding the build quality - we strongly believe in buy-it-for-life philosophy, and the chassis is designed with repairability in mind [1]. Battery life is also one of the top concerns for us and we don't want our users to take the calculator out of the drawer after a long period only to find that the battery is dead. We've had suggestions to add a color screen or OLED display, but that would eat into the battery budget by a few orders of magnitude.

We are also launching DM41X[2], about 100 units have been sent out for beta testing and should be in production later this year.

We appreciate feedback and would love to hear from you: neil[@]swissmicros.com

[1] Teardown: https://www.youtube.com/watch?v=Ong91Ji3iDk

[2] DM41X: https://www.youtube.com/watch?v=UrU4sGWt45M

I have very little need for a calculator of any caliber, but this narrative makes me want one on my desk. I wish that mindset was financially rewarded more often.

I only discovered the existence of this company from this thread - thank you so much for making these.

I wish there was a true clone of the HP 48G calculator. HP stopped making the 48G series years ago, and I now handle mine with kids gloves to keep it functional as long as possible. Almost every undergraduate in my engineering department had a 48G as well as about half the graduate students. I soon became a convert. (I used the HP 32S and then, later, the HP 48G extensively over the decades.)

Over the last few years, as I read calculator related threads here and elsewhere, I became discouraged in hoping to ever see the HP calculator designs I loved so much long ago from ever being available again. I haven't yet read through this thread yet, but the comments in the other threads always seemed to be dominated by people that don't understand the needs of scientists and engineers working in the physical world (not in software development), people that don't themselves need such a calculator and can't see a use for one, and/or people that are extremely negative towards well proven designs of yesteryear without understanding their utility.

Hi Neil,

I just wanted to echo the other comments and strongly endorse their products. I have a DM15L, a recently-bought DM15, (just so I can carry it with me everywhere I go!) a DM16, a DM41L, and a DM42, and will absolutely get a DM41X when it's released! You might call me a bit of a fan.

If you are a fan of HP calculators, but can't stand how expensive they are on eBay, do yourself a favor and pick one up. They're wonderfully constructed and from what I can tell, extremely faithful to the originals (that are out of my reach, unfortunately.)

Also, Neil--I emailed you a question I had about my DM42, in case you can clear something up for me.

> Teardown: https://www.youtube.com/watch?v=Ong91Ji3iDk

That video doesn't strike me as particularly flattering.

I'm no calculator aficionado, but just watching it already had me experiencing pangs of buyer's remorse and no money had even left my pocket.

Echoes of the clamshell sharp zaurus; a well built piece of hardware with very poor software support relegating it to dust collector status.

The reviewer is very enthusiastic about the calculator and loves that thing. How can a teardown be more positive and flattering?

Their enthusiasm more or less ends where the hardware ends and the software starts.

Some demonstrated flaws from memory:

- Inexplicable help file error right out of the hole

- No way to actually display values using the exceptional precision because of the software

- Basically no included graphing capabilities despite having a pixel-addressable e-ink display the buyer is no doubt paying extra for

- Weird font rendering bug and seemingly pointless font scaling

- No modal alphabetic keyboard entry when attempting to do some rudimentary programming

Just to shed some thoughts around not adding features - keep in mind that DM42 is a "homage" to the original HP42. If we go ahead and make major changes to the UI (besides what we have already made to take advantage of the screen), it is no longer a true to the aforementioned spirit. Graphing capabilities were rudimentary on HP42S and you need a printer to plot. Similarly, DM42 has an IR sensor and complete backwards compatibility with HP42S printer.

There is a deliberate attempt to not add features, and to keep DM42 compatible with HP42S "interface". We've received strong feedback from our users to not make major changes to the HP42S spec. One can just use HP42S manual and everything should just work. It is the same with the key layout.

If you want to add features or mess around with the firmware, it is open source. There is also an SDK that you can use to write your own firmware if you wish.

Furthermore, there are some exciting projects to build a new RPN platform all together - WP43 is one.

That said, all feedback is welcome and appreciated. Thank you.

That's fair, like I said I'm no calculator aficionado and have zero prior experience with the HP42. So I'm coming at it cold and those choices are coming through as defects and an inability to make good use of the hardware being purchased.

> That video doesn't strike me as particularly flattering.

What about it struck you in such a way? It looked rather clean and elegant to me.

See my reply to sibling

Still have my zaurus. Too slow to use now but Okish as a linux machine.

Do you ever plan to do the same thing for the HP-48 series?

Definitely, we have intentions and there are significant challenges, but certainly on the horizon.

Great! I'll buy one without hesitation.

I still have my beloved HP-48 GX on my desk, I created a multitasking kernel and a few apps for this hardware while I was a student (1998)

https://www.hpcalc.org/details/79

If you want some input or beta testers, I'm in :)

HP-48G sitting on my desk right now. Onza sticker on the back and my childhood 7 digit phone number on the original nameplate, scratched in with, I'm pretty sure, a Pentel Quicker Clicker.

Oooh, colour me interested. Is there a mailing list or something I can subscribe to for development updates on an HP 48-alike?

Not yet, but we will be launching a new store/branding shortly, there will be a place to sign up for newsletters.

Wow, that would be an instant buy from me on release. Good luck!

As soon as I saw this, my first thought was "where did my HP-49G+ end up?"

Looking at the DM42, it'd probably be good enough for the "not going to use Matlab for this" day-to-day math, but man did that '49 save my bacon a lot of times. Nothing like being able to readily invert a big system of linear equations and take integrals during an exam!

I really hope we'll see the day sooner than later for color eInk displays to make it to mainstream devices.

I just want an eInk monitor that isn't obscenely expensive to write code on and read books and articles, I don't even care if it's black and white. I know many people would use it if created, it's so much more pleasurable to stare at for hours.

Thank you so much for posting info about this calculator! This looks extremely similar and almost identical to my beloved HP 50g graphing calculator, which I still use. However, the HP 50g has been discontinued. Thanks to you, now I have a perfect (and even better) replacement!

You can also have it in you pocket all the time with Free42 and a skin I made: https://github.com/StreakyCobra/dm42-skin

"Almost" have it though, because the display is a bit different on the real DM42, but all functionalities are the same otherwise.

Ha, that brings back memories from high school.

Some classes had HPs, other TIs, it was like Vim vs emacs during puperty.

I was in the TI-85 class and we programmed the heck out of the devices (for cheating too, obviously). I re-wired the link cable with a phone cable and was able to chat over that link with class mates 5m away.

Can you use it on the SAT? Otherwise, I don't think this would be relevant for 99% of the people who own a TI calculator. (I appreciate you sharing it here anyways: just saying that it's not a replacement for most people.)

Definitely not. The requirements on https://collegereadiness.collegeboard.org/sat/taking-the-tes... say:

> Only the calculators listed on this page are acceptable for the Math Test—Calculator portion of the test.

The page has a table of calculators which does not include the SwissMicros DM42. The brands present on the table are Texas Instruments, Casio, Helwett-Packard, Radio Shack, Sharp, Datexx, Microtona, NumWorks, and Smart2.

If you had one of SwissMicros scientific calculators (rather than the DM42, which is their only graphing calculator), you could try to bring it in. Farther down the page:

> Calculators permitted during testing include:

> * Most graphing calculators (see chart) > * All scientific calculators > * All four-function calculators (not recommended)

So you could make a solid case for bringing in a scientific calculator which doesn't have any of the disallowed features (wireless connectivity, QWERTY keyboard, touch input...), but a proctor might still tell you it's not on the list of specifically-approved calculators and therefore not allowed.

---

Amusingly, some of the allowed calculators have disallowed features. Off the top of my head, the HP 50G has wireless (infrared) communication, and the HP Prime has a touchscreen.

As far as infrared communication, they didn't have problems with HP48 like 20-some years ago. i think the rationale was that it only allows limited short range communication, thus was not much of the concern.

Though, I'm curious why some of those "disallowed features" exist, particularly for keyboard and touch input...

They don’t want you to write down full length questions into the calculator for taking out of the test site. It’s just hard enough to type a sentence on the TI-84 that nobody would bother, but a qwerty keyboard that you could touch type on would be a different story.

When I was a student, every middle school student with a TI-83+ was keeping notes in the BASIC editor, and the future programmers were all automating their work in BASIC. Teachers started wiping calculators before exams, and kids started backing up their files to the calculator's ROM to work around it.

Remember, this was the age of T9 typing, we weren't gonna let the lack of a keyboard stop us...

I always found notes and books for open book tests to just make things harder. Sure, a single well made cheat sheat could be invaluable, but in general if you didn't know the material nothing was going to help you if you had to show work, which you do on all non-bubble-sheet exams.

My age might be showing, but tests back then were rarely open book and largely based around memorization and essay writing.

I've only ever had a handful of open book tests in my life, but I just mean that even when you're _allowed_ aids, they're not actually useful unless you have some base understanding anyway.

As someone whose first experience programming was in writing a text-based adventure game on the TI-83, I beg to differ.

> It’s just hard enough to type a sentence on the TI-84 that nobody would bother

Are you sure about that...

They probably know infrared never works anyway

No, you definitely cannot use this calculator on the SAT. I also think that the College Board posts a list of permitted calculators.

Thanks for that link. While I have little use for a graphing calculator these days, the DM-16 is something I could use all the time. Ordered one :)

That doesn't look like an e-ink display to me? Perhaps you meant e-paper? Or do they have one that is actually e-ink?

Not quite e-ink, but a proprietary memory display manufactured by Sharp Japan, like the one sold on Adafruit: https://www.adafruit.com/product/3502

I believe the Pebble smartwatch used such a display.