Well everyone, because I am continually disappointed whenever I read a thread online which doesn't reach any conclusion (relevant xkcd here: https://xkcd.com/979) I am posting a conclusion, although the project is not finished yet.
Basically, the keypad is implemented as a daisy chain of PISO shift registers, and the partial schematic posted is correct (ignoring U10). U10 is actually a 4094 SIPO shift register, but its purpose in the keypad is not obvious. It's not needed to get keypress data out, so it is being ignored for now.
This is a very niche project, and it's unlikely that anyone else has the same hardware, or wants to do the same thing with it, although OP's announcement that it's obsolete and doesn't work with new software would seem to imply that there ought to be hundreds of these up for grabs on the second-hand market.
Now that we can extract a complete snapshot of all the keys we can build a USB HID keyboard using a popular microcontroller.
Fin.
Basically, the keypad is implemented as a daisy chain of PISO shift registers, and the partial schematic posted is correct (ignoring U10). U10 is actually a 4094 SIPO shift register, but its purpose in the keypad is not obvious. It's not needed to get keypress data out, so it is being ignored for now.
This is a very niche project, and it's unlikely that anyone else has the same hardware, or wants to do the same thing with it, although OP's announcement that it's obsolete and doesn't work with new software would seem to imply that there ought to be hundreds of these up for grabs on the second-hand market.
Now that we can extract a complete snapshot of all the keys we can build a USB HID keyboard using a popular microcontroller.
Fin.
Statistics: Posted by ame — Sat Sep 14, 2024 11:06 pm