Power extender for smart-home controllers using 2-wire communication

#This patent specification relates to systems, methods, and related computer program products for powering controllers for energy-consuming systems or other resource-consuming systems. More particularly, this specification relates to an intermediate device, or power extender, between an environmental system and a controller that allows the controller to harvest power from the environmental system while simultaneously commanding the environmental system to perform an environmental function.

#Early thermostats used a bimetallic strip to sense temperature and respond to temperature changes in the room. The movement of the bimetallic strip was used to directly open and close an electrical circuit. Power was delivered to an electromechanical actuator, usually relay or contactor in the HVAC equipment whenever the contact was closed to provide heating and/or cooling to the controlled space. Since these thermostats did not require electrical power to operate, the wiring connections were very simple. Only one wire connected to the transformer and another wire connected to the load. Typically, a 24 VAC power supply transformer, the thermostat, and 24 VAC HVAC equipment relay were all connected in a loop with each device having only two required external connections.

#When electronics began to be used in thermostats, the fact that the thermostat was not directly wired to both sides of the transformer for its power source created a problem. This meant that the thermostat had to be hardwired directly from the system transformer. Direct hardwiring a common “C” wire from the transformer to the electronic thermostat may be very difficult and costly.

#FIG. 1 illustrates a smart thermostat with an electronic display presenting information, according to some embodiments.

#FIG. 2 illustrates a user's hand being present near thermostat that is mounted to a wall, according to some embodiments.

#FIG. 3A-3B illustrates a smart thermostat as viewed from the front and the right, according to some embodiments.

#A smart thermostat refers to a thermostat that can communicate via a network and allows a user to interact with the smart thermostat from a remote location, such as via a mobile device (e.g., smartphone, tablet computer, desktop computer, laptop computer, etc.). Additionally or alternatively, a smart thermostat has advanced features such as sensing as to whether any persons are in the vicinity of the smart thermostat and adjusting a setpoint temperature of the thermostat based on the sensed occupancy.

#When a smart thermostat is installed, such as in a user's home, the user may desire that the smart thermostat be relatively easy to interact with and is also aesthetically pleasing. Embodiments detailed herein are directed to smart thermostats that can include a touch strip that is used by the user to provide input directly to the smart thermostat. In some embodiments, the touch strip is the only user interface present on the smart thermostat. Additionally, the user can interact with the thermostat via an application executed on a mobile device.

#The smart thermostat may have a mirrored cover on a face of the thermostat. When the electronic display is turned off, the mirrored cover may have the visual effect of appearing to be a mirror to a user viewing the face of the thermostat. When the electronic display is illuminated, the mirrored cover has a sufficient transmissivity to allow the illuminated portion of the electronic display to be viewed by the user through the cover. In some embodiments, the cover does not have any cutouts, holes, lenses, or variations on the front surface that could be visible to the user.