The technique here is to use 2 steps switching. Find a timer that you can set on time and off time. Set the turn on time to before sunset. Try 5pm (if you live in PST) then off at say 12:00 midnight. Plug in the power the Timer then plug the photo sensor to the timer. Here's how it work. The timer will turn on at 5pm but if not yet dusk the second switch is still off. After sunset the photosensor(light sensor) will be trigger and makes the light on.

Even the photo sensor is on and the off timer reach the light will turn off. This is called AND series of switching. The 2 switches should be ON to turn on. If any is OFF then the output is OFF. You can buy the sensor in any Home Depot store, Walmart and other electronic store. The passive motion sensor switch works as it detect the changes of temperature. The active motion sensor switch uses trigger like cut-off, lazer or line in sight.

Posted 2010-09-10 and updated on Sep 30, 2010 10:27pm by noel