Patent 9127853 was granted and assigned to Google on September, 2015 by the United States Patent and Trademark Office.
A sleek, low-profile wall-mountable thermostat for controlling an HVAC system is described. The thermostat includes a ring-shaped controller that rotates about a central axis, and an optical sensor directed away from the central axis and toward a radially inward-facing surface of the ring-shaped controller so as to accurately detect optical signals indicating controller's rotational movement.