EEVblog #1159 - World's Most Precise Pocket Calculator

One item mailbag!
A look at the Swissmicro DM42, the world's most precise pocket calculator.
A clone and improvement of the famous HP42S, with open source firmware based on the Free42 platform.

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[EEVblog]

UPDATE: It can display more than 11 digits, press and hold Shift SHOW.

[schwartzenheimer]

At the risk of giving away my age, my first-year chemistry Prof said, "A calculator is a device by which a freshman can determine the wrong answer to eight significant digits".

[mbjac]

I wish I was as enthusiastic with my entire life as this man is with his calculator

[Micetticat]

This is definitely a "right to repair" friendly device: Open source firmware, off the shelf microprocessor and even instructions on how to take it apart written on the PCB!

[ElmerFuddGun]

7:51 - They need the *black solder mask* since you can see the PCB through the openings for the keys. One time when using a black solder mask is actually the right choice!

[pascalcoole]

5 years ago after watching this video I decided to buy the DM42 and never regretted it.
Great device, also have the DM15.

[michelevitarelli]

Rpn calculators was always fun to loan out to a unsuspecting student who forget their calculator. HP for the win!

[bradhayes]

As a mechanical engineer I accumulated a lot of old hp calculators over the years. I have hp 41CV, 15C, 28S, 20S, 48G, 49g+ calculators. I've also got an hp calculator IR thermal printer and paper. Plus a few more older hp calculators I can't remember right now. The older models with the "rocker" style keys were the best in my opinion. You could fly through a long calculation by just tapping the keys without having to watch the display to make sure you didn't get multiple digits with a single key press. Ti calculators with their "floating" keys had a bad habit of giving you a screen full of 7's or some other digit with a single key press. This was a problem Ti calculators had especially when they got older. The original hp "rocker" top-hinged keys with tactile feedback were great. Unfortunately, later and current hp calculator keys are ok but not as good as the original keys. I also had a Ti 59 with magnetic card read/writer and cradle with thermal printer with two optional math modules. I gave it away to one of our drafters back in the late 80s.

[MiniLuv-]

DM42 stands for *D* igital *M* ultimeter with the answer to life, universe and everything.

[Falcrist]

I have this calculator on my desk now, and I'm yelling things at the screen. :D
You can see the full precision with "show" (second function of the decimal key). You can also subtract 9 from the result of the calculator forensics result to see the leftovers. :)
You can upgrade the whole thing online, of course... but even better, you can download programs and save them. Hell, you can even change the pictures that come up when the calculator is off. I've uploaded a bunch of NASA-themed pictures on the DM42 forums.

Too bad I only use it to convert between hex, decimal, and binary these days. Oh well. At least I can convert in STYLE!

[ocudagledam]

David: *opens the package excitedly*
My better half: "Honey, what are those noises, what are you watching?!"

[NorbertHarrer]

I am still using an HP48 up to this day. I have other HPs and TIs as well. But that one is my favorite by far. If SwissMicros ever builds a clone of the 48, I will buy it.

[TheSkogemann]

@1:30 - Had to turn it down... sounded like i was watching a porn xD :) :P :D

[poptartmcjelly]

Did the sin->cos->tan trick on my TI-82 and it returned a
My disappointment is immeasurable and my day is ruined.

[davidsandy]

Thanks for this. In college I started with an HP21, Currently use the HP42S. HP makes the best calculators. Go RPN.

[jonathonpye]

I've loved my HP42s for the last 22 years. Gonna get myself one of these for everyday use though, I think I'll look at a landscape one as well. Thanks for making this video.

[Satchmoeddie]

HP 41 with all the ROM packs. I have land surveying, cut & fill. My father was a civil engineer & hydrologist. Now he is a hydraul-o-ghost. RIP Dad. His ashes went into some of the rivers he did work on. The Arkansas River, The Rio Grande, The Pecos, The Mississippi, The Salt & Gila which flow into The Colorado. The Gunnison which flows into The Colorado. And just for fun, Paradox Canyon. What is the paradox of Paradox Canyon? The river flows out of both ends of the canyon. It's a great way to get lost.

[LiLi-orgm]

Still using my HP 32S I bought new back in 1988. The keys are just as wonderfully tactile as they were 30 years ago!

[SirManlyPowers]

nitpicking... at 2:59 the binary floating point 128-bit box is highlighted, but per the website the calculator uses a decimal floating point 128-bit library- which makes sense for a calculator application. Also, that chip is a cortex-M4 which has 32-bit binary float hardware. I wonder if that gets any use in the firmware?

[wither]

Pff my Nokia 900 has *arbitrary precision* (until you run out of heap space) with GNU MPL and that suckers 10 years old. I had a crappy TI83, then an awesome (nonplatinum!) TI89, but often yanked my fathers HP48. The 15, 42 and 48s and the last run of 50s were absolute killers. HP Laserjet III's (still running, half a million page count!), the 3458 8 1/2 digit DMM, man oh man.

Fiorina absolutely gutted that company taking it from 50 years of rock solid engineering into just a tragic shell, just so she could see a quarterly share price bump (that'd last half a year before investors realize they have no good products or engineering left, dumping the market cap to 1/10th the original value) and pay herself a performance bonus.