Postby Garth » Tue Aug 23, 2022 7:56 pm

A search for "PX41C" on this forum comes up empty, so I'll mention the little calc here. I was just made aware of it on another (non-HP) forum.
eBay item number 325269384765
What it says there is the following [and my comments are added in italics and brackets]:

PX41C a HP41C calculator kit. [but apparently the seller assembled the kit, and he is selling the unit assembled]

A fully hand-assembled PX41C.

Includes a 3D-printed bumper case.

hardware emulating the classic HP41C calculator


  • all thru-hole parts (easy to handle and solder)
  • Runs about 4x faster than the original.
  • memory registers: 3.5 times more memory than the original [So is it effectively a 41cv instead of a 41c?]
  • continuous memory (Memory is not lost when calculator is turn off).
  • auto power off
  • Runs on a single ATMEGA328 8-bit microcontroller running @ 8MHz (same as Arduino Uno)
  • speaker for audible keypress feedback
  • 192x64 LCD
  • display backlight
  • Has a real-time clock. (Uses a 32.768KHz crystal.)
  • Uses a single CR2032 3V battery.
  • Power consumption: 1µA off, 350µA idle, 3mA working (this is with speaker and backlight off)
  • Microcontroller comes preprogrammed.
  • Can run any of the Voyager series and HP41C calculators, downloading the appropriate firmware.
  • Top and bottom aluminum panels.

See YouTube video: https://www.youtube.com/watch?v=5On8Tb-Uc00

Posts: 281
Joined: Tue Jan 20, 2009 1:31 am

Re: PX41C

Postby BillBee » Wed Aug 24, 2022 11:24 am

Hello Garth,

IIRC its $75 US assembled and $65 US not assembled (not including shipping).

It does look tempting and I look forward to someone putting it through the wringer. :)

Have a great day,
Posts: 16
Joined: Tue Apr 20, 2021 2:06 pm

Re: PX41C

Postby mike-stgt » Wed Aug 24, 2022 11:14 pm

Since this site and its forum is about all HP41 and emulators thereof it's a nice idea to mention also an emulation built in a nice case with buttons. But because in these inflationary times the price might change quite quick, I suggest to show the link to the author's site.
IMO there are two possibilities for an experts challenge, i) find out why the self-test of PX-15c shows ERROR 9, or ii) find out how the firmware of the original HP calculators is stored within the Intel hex files.
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