Door sensors on every cabinet in the kitchen At this point, I have yet to actually touch an Arduino.  I'm toying with the RPi3 along with Home Assistant, but I'm always thinking of ways to do useless things that are fun.

Let's say I had a kitchen with 32 cabinet doors and drawers and I wanted to make sure that each one had a switch that would detect a simple on/off state.  That would translate to a map whereby a visual indicator would show that something's "ajar."


Is this the best approach to achieve this goal?   
How many Arduino boards would this require, and/or are there other methods or concepts to achieve the same ultimate goal?


Thanks!
Touch less sensors (IR, magnetic hall), detecting drawer state.

1pc Arduino with I/O expanders to increase I/O ports.