HP41 MLDL2000 V2 demo


For those interested in the MLDL2000 for the HP41, I uploaded a video to youtube with a demonstration of the various possibilities of the MLDL2000V2, using the mbed module for adavnced I/O (networking, USB media etc). The project is currently still in the breadboard phase, but with the basic mbed functions done I can now start on completing the schematics and layout.

Many thanks go to Marcus von Cube for his support with some of the network functionality and creating the Java applet showing the HP41 stack.



Thanks for the credits. The video is well done.


Hi Meindert, looks like you're on a roll again - superb advances, I look forward to the MLDL_V2 with all that functionality built-in... there's no end in sight for the 41!


There is still some work to do. If the mbed becomes part of the MLDL design, the power consumption will rise significantly. Either, the MLDL becomes a stationary device or it gets big enough to carry its own power source.

Creating something around the low power ARM designs (see HP 20b) might help but the mbed is not just hardware. It lives from the software environment and ease of development.


Power consumption has always been a concern, and that is the reason why the mbed module is optional. Apart from that, power to the mbed can be switched on or off under HP41 control. Basically I do not see much mobile use for the HP41 with MLDL2000 (I prefer to use my iPod with i41CX when on the road). I case where low power mass storage is needed, there is the option of using the GHI uALFAT module for micro SD cards. The pinout of the MLDL2000 will allow either module.

The mbed exapnsion was done to show it is possible, and the fact that it allows very easy adaption by the user thanks to its ecosystem and endless possibilities. Please do not regard the MLDL2000 as a finished and closed system. It is intended to be used and modified in ways that I have not thought of ...



Looks like a superb device that really brings the 41 series up to date.

This plus the 41cl CPU.

- Pauli


brings the 41 series up to date.

I guess you're technically right Pauli, but for some of us (i.e. old enough) the 41 has always been "up-to-date" :-)

If not, consider:

- MLDL itself

- Clonix, NoVRAM

- PIL-Box..

- and last but not least, all the "new generation" software!

Oh well, as I said before... dream on!


I guess I didn't express myself well. I've been using a 41 as my day to day calculator for a while now (replacing a 15c) and it isn't lacking much.

However, for those of us without any peripherals, this will be a godsend. IO and mass storage are what I'm lacking and HP-IL isn't really modern.


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