Building blocks for a smart device such as a thermostat include a user interface (UI) unit and a terminal (TML) unit. A UI unit may support one or more input data from a user and/or sensors and/or one or more control terminals. The UI unit may process each input datum or a combination of the input data, generate a control signal to one or more control terminals based on the processing, and send the control signal to one or more control terminals over a communication channel. A terminal unit, which may consist of one or more control terminals, transforms the received control signal into one or more controls to one or more associated environmental generators. One or more UI units may control one or more controlled apparatuses in conjunction with a mobile app to allow a unified user experience.