Self-powered long-life occupancy sensors and sensor circuits
View Patent ↗Occupancy sensors are provided that do not require an external power source in order to operate. The sensors operate with a low voltage non-rechargeable battery and are fully functional for at least about 15-20 years. The sensors include a relay output capable of switching high or low voltage and high or low current with virtually no generated heat. The sensors require no warm-up period, no minimum load, and no external ground connection. The sensors are always active and are easily installed, having two electrically interchangeable outputs for coupling to, for example, a load and a load power source.
1. A method of coupling a first relay output to a second relay output based on occupancy sensed within a designated area, said method comprising:
driving a relay driver into a first state in response to said occupancy sensed within a designated area;
coupling said first and said second outputs together in response to said driving; and
powering said driving and said coupling with a non-rechargeable battery providing no more than about 3.6 volts.
2. The method of claim 1 wherein said first state comprises applying a voltage pulse of a first polarity across a relay coil.
3. The method of claim 1 further comprising:
driving said relay driver into a second state in response to no occupancy being sensed in said designated area; and
decoupling said first and second outputs from each other in response to said driving into said second state; wherein:
said powering further comprises powering said driving into said first state, said coupling, said driving into said second state, and said decoupling with a non-rechargeable battery providing no more than about 3.6 volts.
4. The method of claim 3 wherein said second state comprises applying a voltage pulse of a second polarity across a relay coil.
5. The method of claim 1 wherein said coupling comprises coupling said first and second outputs together using a relay coil with no more than about 3 volts provided by a said non-rechargeable battery in response to said driving.
6. The method of claim 1 wherein said first output is coupled to a load and said second output is coupled to power for said load.