Thank you for the link. Attached is code and a revised schematic. Remove the .txt to open in the PICAXE program editor.

I apparently set U3 and U4 to the same I2C address in the first schematic, so that's been corrected. I also moved around the connections between the MCP23017's and the LED's and switches to make writing the program easier. I forgot how intricate matrices get.

If your switches already have current-limiting resistors to allow them to accept 5VDC, you can leave off R5-R14. I think the MCP23017 has an option for using internal pull-ups which, with a little redesign, would allow us to eliminate R15-R24, but I'm pooped, so I'm leaving this as-is.

Theoretically, the code will work. In reality, however, let me know when you run into snafus.

Once you've got everything up and running, please post a picture of the completed project and let us know what feedback you get.

 

fantastic thank you, i will put it all together and post the results
great effort,damn that´s a lot of code.

 

Lot of code? Oops, I was working from another project and didn't save it before I posted it. Here is the cleaned up code. Sorry about that.