Patent ID: 8884532

Claim:
A method for controlling a luminaire, said method comprising the steps of: (a) sensing a level of ambient light proximate to a luminaire connected to a source of electrical current, said electrical current alternating between a positive voltage and a negative voltage, said source of alternating electrical current having a period, said alternating electrical current being in electrical connection to a relay which is in electrical connection with said luminaire so that closing said relay connects said alternating electrical current with said luminaire and opening said relay disconnects said alternating electrical current from said luminaire; (b) de-energizing said relay so that said relay closes as said alternating electrical current crosses a zero voltage level between a negative and a positive voltage, using said period of said alternating electrical current to predict said zero voltage level, in order to dis-connect electrical power to said luminaire when said level of sensed ambient light rises above a pre-selected light level; (c) energizing said relay so that said relay opens as said alternating electrical current crosses said zero voltage level, in order to connect said electrical power to said luminaire when said level of sensed ambient light falls below said pre-selected level; and (d) alternatingly energizing and de-energizing said relay in a series of short pulses when said relay does not open to urge said relay to open.