How to interface a keypad with Arduino and Simulink?

Hello,

I am currently working on a project in which I need users to type in values onto a keypad. Currently I have the code working on Arduino but the project would be easier in Simulink. I have tried interfacing the digital pins to tell when pins go high when a button is pressed as well as using Arduino code in Simulink but neither have worked so far. Has anyone found a way to make this work?