Motion detectors would be a very good way to go. But I'd still want switches for extra lighting in many cases. Either way, some kind of mechanical or electrical switching of the 120V is taking place under control of something at 12V or less. If the motion detector logic can switch it, a momentary contact switch driving similar logic should be able to also do the job. There are lots of things around that can control 120V or more from 12V or less, such as all that X10 stuff (which I don't want for other reasons), and is presumably listed. So I shouldn't need to use those expensive industrial contactors.
