Calculator blog

Musings and comments about our common interest


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Possible improvements to HP15c firmware

overlay_-_1What could be improved on the HP15c CE by changing the firmware?

  • Back up: in my opinion, the ability to write down user memory (including memory disposition) would be fantastic. not only you save your hard-entered programs, but you could store different profiles (EE, algebra, finance, others...) and change them "on the fly"
  • Memory is now far less important - we have enough! there are some methods to bring it to 224 registers, but what's the point?
  • Debouncing time adjustment - a little like screen contrast?
  • Any other that you can imagine?
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Why HP15c CE "Enhanced" ?


We are offering theHP15c CE "Enhanced" at a 10€ premium over the standard price of the HP15c CE.

What makes it "enhanced"? 4 main items, in my opinion.

  • We implement the latest firmware with a correction for the HP16c hidden mode, so that it is not affected by the DEC bug.
  • We include a HP16c overlay so you can use the HP16c mode with ease.
  • We include a programming cable so that you can change the firmware when new versions appear with more functions or solutions for yet unknown bugs. (In particular we are working on a back up feature - memory is big enough to save it just in case. Alternatively, you can have several profiles (finance, electrical, construction, algebra) that can be changed with the back up feature)
  • My preferred: a proper QC done by me. I open the calculator, see whether the bezel has any spot, and test the keyboard. In particular, I test all keys for recording properly using the self test feature, for any hard key (is fair to say that this test does not test for rebounds, but our new firmware also changes debouncing to 100ms from 80ms in the original machine)


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The HP15c and HP16c in HP Journal of May 1983

If you have time for an interesting read, please take a look at the two last articles on May 1983 issue of HP Journal:


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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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