I'm building my 4X4 matrix keypad to a 5X5. The first step for me is to add an extension cable that lets me wire in the extra two pins needed.
The issue I'm having is that adding a simple extension cable causes the 7 key and the * key to both read as *.
I have installed the resistor and pull-down resistor needed, but I'm wondering if adding some 1N4148 diodes to the keypad inputs would eliminate this issue?
If that's likely to help I can just replace the orange jumpers 0-4 with the diodes, or should I do 5 up and 5 down?
I've attached pictures and the modified files.
**After everyone's help, I just ended up making a keypad that doesn't leak**
**Pictures and code below**
**Thanks everyone, this was a huge help**