🚀 go-pugleaf

I'm toying with the idea of putting some small motion 
detectors throughout my house in key locations.  I hope
to have them all monitored by a simple micro-p. 

In my mind, the ideal sensor would be something like the
rangefinder in poloroid cameras (small, low power, etc).  
Although a rangefinder might be more accurate than I need--all
I really need is something that well register a change
when a large (human) size movement occurs near a door
or in a hall way.

Does anyone have an idea of a manufacturer/model/source
that might work for my purpose?

Any idea what the interface is like?

Any idea of price?

Anybody had any luck with the idea already?

Thanks in advance,

Dean.