Author Topic: EEVblog #1159 - World's Most Precise Pocket Calculator  (Read 762 times)

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Offline EEVblog

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EEVblog #1159 - World's Most Precise Pocket Calculator
« on: December 17, 2018, 11:58:33 pm »
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.

https://www.swissmicros.com/dm42.php
http://thomasokken.com/free42/


 
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Offline dr.diesel

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #1 on: Yesterday at 12:39:50 am »
That is quite nice!  Is the display cover glass or plastic?

Online imo

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #2 on: Yesterday at 04:27:58 am »
I think the "most precise pocket calculator" is the WP-34S.
https://sourceforge.net/projects/wp34s/
It uses DecNumber library with up to 50 decimal places precision.
« Last Edit: Yesterday at 04:32:15 am by imo »
 

Offline bsudbrink

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #3 on: Yesterday at 08:19:13 am »
Just so you know, YouTube has this video marked as "unlisted".  I'm not sure what this means, but I don't see it on my YouTube account subscription page.
 

Online darik

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #4 on: Yesterday at 10:53:41 am »
To show the full precision, use shift-decimal (SHOW).
 

Offline Dubbie

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #5 on: Yesterday at 11:56:26 am »
I have this calculator, the only issue I have with it is that the button feel is not as nice as it could be. It is my daily driver at work though.
 

Offline EEVblog

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #6 on: Yesterday at 01:13:37 pm »
To show the full precision, use shift-decimal (SHOW).

Ah, that works, but unfortunately does not show up long enough to read it!
UPDATE: You have to continue to hold down the button to keep it showing

« Last Edit: Yesterday at 01:15:55 pm by EEVblog »
 
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Offline EEVblog

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #7 on: Yesterday at 01:17:54 pm »
Actual Calculator Forensics result:
 
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Online imo

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #8 on: Yesterday at 02:35:20 pm »
It seems Dave's buttons died :)
A big pain all these recent attempts to mimic the original HP-clicky buttons. The WP-34s (HP-30b hw) I own still clicks, but mostly because I stopped using it in order to save the buttons :)
The thin plastic pins (about 2.5mm long 1mm dia) pushing onto the metal dome usually bend/broke when pushing a little harder.

The DM-42 does not use such long pins, it may last a little bit longer. Not sure you get such HP-feel with it, however.
And my HP-25 and HP-48GX is still clicky..
« Last Edit: Yesterday at 02:39:08 pm by imo »
 

Offline BrianHG

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #9 on: Yesterday at 02:52:42 pm »
Holly cow Dave!  Your enthusiasm shines through to the moon.  :-+
__________
BrianHG.
 

Offline inOr

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #10 on: Yesterday at 04:41:53 pm »
Once I tried to write a DEC Fortran program to solve a quadratic the high school way, the exact formula you know -b+/- sqrt(b^2 ...., I got a ridiculous answer, so I tried a numeric routine from the DEC collection and wow was that wrong!  So I programmed my own numeric routine and that worked.  Meanwhile, I used my HP xx scientific calculator.  I can't remember the precision, but the answer was bang-on.  They do have their uses...
 

Offline johnlsenchak

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #11 on: Yesterday at 04:49:01 pm »

Years ago,   I had a  real nice  programmable HP scientific    calculator    where I  wrote a programs  to  calculate  A/C   circuits when  it came to inductors and  capacitors   .
John Senchak "Daytona  Beach  Florida "
 jls (at)  antihotmail.com   http://www.antihotmail.com
https://www.facebook.com/john.senchak.1
 

Offline Fungus

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #12 on: Yesterday at 10:55:17 pm »
To show the full precision, use shift-decimal (SHOW).
I was shouting that at the screen while the video was running.  :popcorn:

Ah, that works, but unfortunately does not show up long enough to read it!
UPDATE: You have to continue to hold down the button to keep it showing

How many does it show? 12 digits?
 

Offline NivagSwerdna

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #13 on: Today at 12:38:24 am »
Nice.  I have a poor man's version WP 34S .  I know 42S is super popular with the fanboys but IMHO it's a bit hard to live with unless you use it every day since the functions are hidden away... I think I prefer the ones that just have lots of functions on the buttons...

I also have a HP35S which is a nice compromise and not bad for a modern device.

 

Offline Gribo

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #14 on: Today at 03:07:32 am »
Does anyone knows who manufactures the display? I have been looking for an E-paper display with fast response time for quite a while.
 

Online imo

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Re: EEVblog #1159 - World's Most Precise Pocket Calculator
« Reply #15 on: Today at 05:28:00 am »
LS027B7DH01 from Sharp Microelectronics..
 


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