Hello,
has anybody such an hardware? where to buy? any recommendation is welcome. The use of magnetic card is NO fun at all.
HP41CV? look https://de.wikipedia.org/wiki/HP-41C
My HP41CV is still running after 28 years.. should be connected into the PC for showing to others that piece is highly modern and wonderfull hightech ;-)

Connect to a PC via what connection?

As a general rule it's a bad idea to post a question where you expect the guy answering to do research. The HP-41CV was 1983-1990, according to wikipedia.

Profit by selling your antique and install speedcrunch for math on your pc. That's my advice.

I m searching serial/usb. but could not find a solution for now. this small project is not efficient: however, this is my old love.. ;-)
Like meeting an ex again.

I know how you feel. My HP41 quite working about a few ago and I miss it....

Seems highly unlikely. There was an interface loop module and even if you did have one you would need to know the signal interface and protocol in order to build something to convert it to USB etc.

The only possibility is serial port (in 1983) at fixed slow speed, e.g. <2400 baud. Folks only had 1200/300modems back then iirc. Download at 1200 baud, upload at 300baud, because the other guy has rung you and is therefore paying. So everyone was using 300 baud.

RS232 also needed ±5V. Does it have -5V?

you kill me.. ;-) this is like asking a blind what is the color of a tomato ;-)
Haha. no idea. It smell like a 3000 USD project I have to give to a family member. However a good project. I think the market is there: some crazy persons like me are ready to pay 250USD for having such an interface. I will ask an electronic engineer friend if he can help in finding a solution (seems to be a hardcore hardware project.. with a linux touch later).

It is possible to build something to interface with the HP41 expansion port.

http://hp41.kuiprs.nl/hp41.htm

Very dodgy.

Everything was unbuffered and voltage sensitive back then. Chips were through hole, which is long obsolete. Even 5V logic is thin on the ground. Electronics is very unforgiving.

First rough idea found here http://www.jeffcalc.hp41.eu/hpil/
- my good old hp41cv, connected to an
- HP-IL module, connected to an
- HP-IL box (from jeff above), connected to an
- rasp pi4 with touchscreen (raspbian and Qt on it), connected to a
- powerbank (for having not cable), all running with the help of
- https://github.com/bug400/pyilper
I see others has made it working with an Arduino board. https://www.hpmuseum.org/forum/thread-1023.html
The next step (from the arduino idea) would be, use a pi4 because it would probably make the same than the arduino and it could print my good old fashioned RPN programs onto my network printer via cups.
I close this topic here.
The documentation of the final result will probably happens anywhere else on a raspi project page.

Looks like too many steps to me I spent nearly 30 years of my life doing this stuff. Unless you can validate every step, that will become one of those projects that sits on your shelf for months at a time. If you actually NEED that data, involve an expert. Don't waste your time building up a diy project to save some old piece of junk. people matter more.

I have 20 other projects which are more valuable (10m³ tank in the garden for watering etc.). This one is for showing to family members what can be done in a SW and HW area (gardening, painting, building, sport, referee, furnitures, human-interacting, job-for-income are other area of action). So, you are right. this is not an efficient one. this is an educational one. And it follow few values and principles which can be applied for SW and HW (projects) https://agilemanifesto.org/ and I will demonstrate this (too) to the family members. AND: this is a bit like upgrading an 40years old car. This is MUCH more valuable for the planet than buying a showing-off modern new electric vehicle with batteries (TERRIBLE the mess its doing and the destructive environmental impact). I like people who are repairing their 30old car (why not with expensive remanufactured parts) and NOT buying a modern new electrical vehicle.. which will make burning the planet. So, I will show (not tell) the family member an upgrading of technology is possible.

Update: WORKS
- HP41CV with HP-IL
- 64its PC with Debian11 and pyILPER (anaconda package)
- Pilbox electonic interface
-> all programs stored in memory can be uploaded/downloaded to a PC
-> no need for a huge notebook in travel situation: quick prototype programming on HP41CV or transport on a boat with a tight plastic bag or..
took only 5,5 months for this project since the question was posted here.