I'm creating a system that will detect whether the garage door is open or closed. In a previous version I used the Neo's internal compass to measure the door position, but I'm going to use a reed switch. I then control two leds to indicate the switch position, and I will use MQTT so send it to my MQTT broker. I'm no hardware designer, so I've based my design on designs I found on the internet. I noticed that when I see switch designs they connect the wire to 5v, even in the 'official' "Getting started with UDOO". I'd like to know why this is, why not the 3.3v?