MULTIMETER DESIGNING

Hi..!!

I am doing a mini project to make a multimeter using PIC16F877A.I have an option to use arduino also.But i am confused. How can i select the modes of a multimeter? should i use a rotary switch or a keypad? If i use rotary switch for mode selection(or range selection),then how the microcontroller will know which mode(or range) is selected?

please suggest me some circuit ideas...

You can learn from this