MLDL2000 plans and new version


After a long period of relative silence I am finally ready to start working on the MLDL2000 again, so I am now giving a short overview of the status and plans.

The current MLDL2000 design is ore or less stable, and no parts are available anymore. My first priority is to implement some features in the software, the most important being the option to upgrade the firmware. This will fix a few minor issues and will allow me to work on a number of aditional features that can be easily implemented by the user.

Based on the current waiting list I have decided to do some more production. After the very good meeting and dicsussions we had in Allschwil last year I started thinking and came to the conclusion that it would be possible to add (at least) one great feature. This would require a hardware change however. Therefore I will do a redesign of the MLDL2000, that will be called MLDL2000V2. If there are better suggestions for a name let me know.

The MLDL2000V2 will have the following additional features:

- Redesign of all 3 PCB's to fix a number of design isssues

- USB Interface will be fully redesigned and will have an extra USB Host controller that will allow the user to add a USB Mass Storage Medium (like a USB stick) that can be accessable from the HP41

- The new USB interface can be used in an existing MLDL2000, replacing the original USB interface

- Since there are no more empty card reader shell available an extra PCB will be designed as a carrier to the other PCBs. This will allow users to have the MLDL2000V2 in an external box

All the designs as mentioned above are in draft and need to be completed. More specifically I need to do some testing to verify if this is all really possible. At the same time I need to have an idea of how much interest there is, so please contact me if you want to be added to the waiting list. Please be aware that it wil take some time before MLDL2000V2 will be in production.

Most important is that I will need some support from the user community to create an HP41 ROM that will support the mass storage on USB, so any volunteers should step forward an contact me.

Please keep watching my website for further news.



Hi Meindert,

The "V2" plans sound great!!

I need to have an idea of how much interest there is, so please contact me if you want to be added to the waiting list.

If I remember correctly (IIRC)..., in Nov'06, you asked if there was enough interest for a second production run of MLDL2000's. I jumped at the opportunity to be added to that list. With these new features, I again want to make sure I'm on the list (whether you're updating the "old" list, or creating a "new" list :-)

Thanks again for your efforts Meindert!



Great plans, Meindert

I have some other ideas for the future of the MLDL2000V2.. maybe one is worth thinking about it....

- HP-IR support: Maybe it is possible to add a HP-IR interface, so that the expensive but usefull module HP 82242A is no longer needed.

- power supply for the HP-41: On my MLDL you added a 6V plug in for a common power supply. Maybe this could be a addition. If not, maybe there is a possibility in your MLDL to add 4-AA cells to avoid the internal Lady-cells. The HP-41 could be driver cheaper with the AA-cells that do not leak that fast. Also the rechageable AA-cells hold longer than rechargeable Lady-cells.

- integration of the HP-IL module: Maybe there is a possibility to add a fourth PCB with the HP-IL module. The MLDL2000V2 would have a HP-IL plug in

- on april 1st I would add a internal radio module, that can be driven and programmed by the HP-41 ;)

Matthias (who is very occupied with his marriage on friday)


If you are going to marry this Friday, it might well be your last week on this forum! Enjoy your last days as a bachelor!



Now for some serious stuff:

- I wanted to keep the April 1 update as a surprise, but with the new USB interface I could actually very easily make an MP3 player from your HP41 by adding just one extra IC ... and this is no joke!

- IR driver would be relatively easy, but I do not have the means to test it or to create the software with it, so this is a nogo as far as I am concerned

- External power is really tricky and can be unreliable, it would also make the box much bigger, but I will look into this a bit more

- Adding IL would be pretty complicated, I suggest you stick with an original IL module



Hello Meinderts,

Please count me in for one of your updated MLDL2000.

Thanks in advance.


Hi Meindert, guys;

I must confess I'm running out of available time this year. Because of some extra activities at the university I'm teaching, I'm using almost all of my spare time to rest a little bit. I do not even have my computer acessing the www at the weekends, I only read my e-mails at the University. Also, the last time I recall using any of my own HP calculator was in December 2006. I do not use the HP41 with the MLDL since October...

But I still want to be part of the MLDL2000 User's Club, and I actually want a new unit plus one spare new USB host controler.

About the mass storage on USB: what is the main idea?

Best regards.

Luiz (Brazil)


About the mass storage on USB: what is the main idea?

I don't know if I understood the question completely,

but as far as I know one of the initial ideas behind this

was to supplement or replace the older HP-IL mass storage devices;-)



Raymond was one of the initiators of the idea of having some mass storage available, and indeed it is my intention to offer USB media as a means to replace card reader and IL storage with virtually unlimited capacity, and at the same time use the media for exchanging information with the PC world.



I would be out-of-my-mind-extatic. When could I get one?


This will take a few months to sort out and finalize the design, so please be patient ...


I am interested too, and very patient, though I would have to hire out to someone I trust like Randy to do the final assembly work. I am hopeless with a soldering iron.

A USB interface with mass storage capability would be something else, though, particularly if the file formats were transportable from HP41 to PC. It would be something to be able to write text code, compile it to RAW with something like hp41uc, move the RAW to a flash drive, and move the program to the calculator with simply plugging the USB flash drive into the MLDL2000. And back again if one likes. Anything to keep one from having to rely on ancient computers and DOS....



Those who have asked me to be on the list for an MLDL2000 in the past can trust that they still are. I will send out a message to all contacts that I have as a confirmation. If you do not get this confirmation from me within a week, please let me know.
If you have only indicated your interest in this Forum, please send me an email, I really need your contact details.




Therefore I will do a redesign of the MLDL2000, that will be called MLDL2000V2. If there are better suggestions for a name let me know.


How about MLDL2007 ?

If you go with that name, do I get a free copy? B^)

dona nobis pacem


you will have to do much better than that to earn something ;)


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