I always preferred resistor divider/ladder based keypads over matrix keypads. If you're clever, all you'll need is one analogue port from your microcontroller to use as many buttons as you'd like. Sure, it requires a bunch of programming, but then again, so does the keypad matrix. In this series of three videos, we'll talk about how the resistor based keypad works, how to interface it with your arduino, and how to program and decode with simple software!
This first video talks about the basic theory and the schematic diagram. Don't worry. All of the videos are short!
Interface & Preliminary Code:
Final Code & Demonstration:
Here is a link to each of the codes performed in part#2 and part#3: Code Samples
Well I sincerely hope that this helps someone out. I hope that you're able to learn from these videos and code samples. Take care, and thanks for taking the time to look at my instructable!