Abstract: A battery-operated automatic electrical switch control device to be mounted on an existing wall switch. A back frame is mounted behind the existing switch plate and a casing containing the electric circuitry and moving components of the device clips around the switch plate and onto the frame. Inside the casing is a printed circuit board wired to a DC motor that drives a cam. The printed circuit board is connected to a sensor or timing component, also in the casing, which signals the turning on or off of the switch. Such a signal, which may originate from a remote control unit or from changes in the local environment, is passed on to the motor, which drives the cam to rotate. The cam follower has on its tip a claw which grasps the actuating knob of the wall switch. The linear movement of the cam follower in response to the turning cam causes the knob to be pushed up or down, turning the switch on or off accordingly.