I'm using the keypad library (http://playground.arduino.cc/code/keypad) with a 4 x 4 membrane matrix keypad.
The problem I'm having is that when no key is pressed it still shows a random keypress on the serial monitor.
I don't know if my keyboard is just very sensitive or if my pins are floating.
I used this keypad successfully with a PIC in another project but in that library u used pull down resistors on my rows. Doing some looking around it looks like I need to use pull ups on my rows? Connect the rows to 5V with a resistor in order to eliminate the floating pins?
Now I'm guessing in software I could use the keystate function to only accept key presses after 50-100 ms.