I have a light out back of my house on a detached garage that lights up the parking area. I would like to run it off of a mechanical timer so it goes on at 5 p.m. and off at 10 p.m. I would also like to put a photocell on the light so that if it isn't dark at 5 p.m. the light won't come on. Now, I would also like to put a motion detector on the light so that after 10 p.m. when the timer shuts off the light will come back on in case I get home after 10 or someone trying to get in my garage would set it off.
If I feed the light from two different sources (same circuit) one through the timer and photocell and one through the motion detector, would I achieve my goal? Will there be a problem with each source backfeeding through the other. I can't imagine the mechanical timer will be bothered by the load side being hot but I'm not so sure about the photocell or the motion detector. Could I (should I) put diodes in to keep them from backfeeding each other? I won't be putting more than a 100-watt bulb in the fixture.
Thanks for any help, Dave