Going crazy here trying to connect a keypad to my Arduino. I followed this article KeypadTutorial, but my guess is something is wrong/different because my keypad only has 9 pins and the far left (pin 1) and far right (pin 9) pins have no traces back to the keypad. I bought it years ago and just got around to finding a use for it. It looks just like this one Arduino Keypad but different with white keys with black font.
The issue is the wrong key shows up (i.e. press 0 and get 9). I used a multi-meter to test for continuity between pins when pressing each key and got results that are kind of stumping me. I would think there would be some kind of pattern (like the first pin would always be a 1, 2, or a 3), but obviously not (or I just have a bad keypad).
KEY(pin1, pin2) 1(2,3) 2(1,2) 3(2,5) 4(3,7) 5(1,7) 6(5,7) 8(1,6) 9(5,6) 0(1,4) #(4,5) *(3,4)