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Calculator blog

Musings and comments about our common interest


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New service - firmware installation

IMG_4647_MedianoNot too many people have a cable to reprogram HP calculators. The HP15 LE cable had the same connector, but it is NOT compatible. You need to make destructuve changes to the old cable to be able to use with the new HP calculators.

Well, we have one, so that we can reprogram these calculators. We are offering that service. Now the important thing is to have a new firmware!

We are testing a couple of possible firmwares that solve the main bug in the HP16c emulation. One of them is working well so far! We'd need to get the permissions, but this one is a strong candidate to replace the original firmware. Too early to decide, though.

We are also considering producing our own cable - industrially. But this will take longer...


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Overlays again

We need to state some things clealyr regarding our overlay:

This is NOT a HP product

The HP16c mode in HP15c CE is Not Manufacturer-Supported. HP and its licensees are not responsible for its use and suitability for any application, and for the bugs that may exist in non-supported modes. The user is solely responsible for the operation in non-supported modes.

This overlay is intended just for exploration of the calculator features and not for professional purposes, and it is designed and produced by The Calculator Store SLNE. The company makes no representation for the accuracy of calculations in HP16 mode, in particular due to the DEC display bug.


Now working on:

  • A firmware update that caters for the mos egregious bug in HP16c : the DEC bug. (I do not want to brag about it, but it was I who discovered it first). There are already candidates to solve the DEC bug - but not the others (very minor in comparison)
  • A cable to perform firmware updates: the 3D design is made, we need now to perform mechanical tests, andf then submit to production
  • Captura_de_pantalla_2023-10-18_a_las_17.40.02
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So far, the definitive video review of the new HP15c CE

Here is the definitive review of the HP15c CE calculator. BTW - the batteries are in parallel to provide 3v.

No association whatsoever with the poster of the video!


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New HP15c batch arrived!

We are shipping now all the pending orders of HP15c, since the boat units of HP15c have arrived yesterday!! Hectic days again.


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All first batch's shipping is over!!

The early orders for the HP15c Collector's Edition have all been shipped. From now on, it is business as usual - normal ordrs coming in and out.

705 orders have been fulfilled for a total of 937 calculators. Several people decided to take 2 or more calculators, profiteering from the discount for more than 5 and more than 10 units built into the price structure.

And in many cases the customers have already received them. We did not use the postal system, just courier companies, with typical delivery lapses of 2-3 days within Europe. 


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some pictures of the units just arrived to Czech Republic

The HP15c first batch of units entered the Moravia warehouse on July 19 - here is how they look! We will ship them to our customers as soon as they reach us!!



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Arrival of units to Europe ( HP15c Collector's Edition )

Forgot to mention that this week the units left the Philippines and are on their way to Moravia in Czech republic. From there, immediately to us and then to you!!!

Also, answering a question to one of our videos in youtube: the firmware date is 2023-01-05


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Difference between leather case and normal case for the HP15c CE

I receive many questions about the leather case for the HP15c CE calculator. 

The first thing to answer is that there you will have the standard case in all cases: choosing the leather case will get you the standard case that is in the box + a leather case.

The second thing is taking a look at the pictures of both:


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The first samples have arrived

...And here is how they look!

(Please also see the HP12c running HP16c firmware !!! )



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Overlays, cover, etc.

We have received several questions about the Overlay option in the HP15CE - so many that we have changed the name to "Cover". 

It is an HP16c overlay to be put on top of the keyboard. It allows the machine to behave as an HP16c if you have the means to transfer there the firmware of an HP16c. It is possible on the newest versions of the HP15c or the HP12c too (NOT Platinum). More details to come in following weeks!


There will be another option for HP15c cover too.

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More about: hp15c, hp16c
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