Can a home motion detector work through frosted or clear glass?
IR (infra red) motion sensors are generally housed behind frosted plastic housings. Camera lenses also let infra red light pass through. Assuming yours is an infra red motion detector, frosted plastic or glass will not be a problem. The frosting is there to block your view of the lens and to "smear" the background contrast projected onto the IR sensor such that the IR blob's motion is better detected.