To ensure that the head unit buttons still work in conjunction with the steering wheel buttons, the Arduino would have to keep the pins as inputs until a steering wheel button was pushed, the pin ...

But if you just want to add in some buttons without reaching for an extra IC you’ll love this hack. [John Boxall] shows how to add four buttons using one ADC pin. The concept is nothing new.

YouTube channel How To Mechatronics has created a great tutorial with full instructions on how to create your very own Arduino powered 3D wire bending machine.