On Sun, 30 Aug 2015 17:44:01 +0000, Dave G.
During the daylight, unplug or disconnect it for a few minutes. Replug
and it should be OK.
I really like the motion detectors but at times they can be a PITA. If
you plug ours in when dark, or after a power failure, it will go on
and off all night but reset the next daylight cycle.