I'm working on a project and I need some ideas on how to sense the presence or absence of a large object through a piece of laminated glass. The sensing distance would need to be adjustable. I would like to be able to place the object a certain distance from the glass, and then adjust the sensor so that a relay opens when the object is present, but closes when the object moves out of range. I'm thinking of a range of about 10-12 feet. The range will vary between cycles, so that makes the adjustability necessary.
I found some microwave sensors that sound like they will work through glass. Is there something that would work better?
I'm really new to the arduino, so this should be a great learning experience for me.
I appreciate any help.