I thought I'd let you guys know about a couple of interesting things from the HP side of the calculator fence.

1- Going very old school, there's a guy who used a Xylinx FPGA to create a new, faster logic board for the HP41 calculator. There's an article about this here

http://systemyde.com/pdf/hhc2010.pdf

and for more information about the 41 series in general, take a look here

http://en.wikipedia.org/wiki/HP-41C

2 - The hp-20b and hp-30b are aparently completely re-programmable, and there's a project to write a new operating system for it. Details are here on sourceforge

http://sourceforge.net/projects/wp34s/

Dave

I don't know if we have many HP users here, but thanks for thinking of us and posting the update! It is cool to know that we aren't alone in our tinkering instincts.

Thanks indeed for these updates, rfdave; I had forgotten that you were an HP calculator user too. On the theme of FPGAs, I always wanted to use an FPGA or even 74LS-series discrete TTL logic to make a giant z80 CPU, and solder it into my calculator as a processor. It would be stunningly awkward but so cool.

How about a gumstix http://www.gumstix.com/store/product_info.php?products_id=211 hacked in with the Z80 side of things acting as a terminal? Running Linux and Octave?

Dave