An optical shutter encoder provides a mechanism for monitoring a state condition of an apparatus. A shutter assembly is adapted to have an aperture that varies with the changing state of the apparatus feature being monitored. An optical emitter and detector are provided to sample the condition of the shutter, that is, to determine if it is open, partially closed, or fully closed. The shutter condition is indicative of the state condition. A series of encoders is provided to monitor repetitive devices of the apparatus; the emitter and detector pair are moved to sequentially sample each shutter, thus providing the state condition of each repetitive device of the apparatus.

A power receptacle 10 includes a housing 12 having a cover plate 46 therefore and securable thereto, an associated pair of receptacle contacts 70 mounted within the housing 12, the contacts 70 each having pair of arms 74 having openings 78 therethrough to define a beam receiving passage 80 completely through the receptacle contacts 70, means for directing a beam of light through the beam receiving passage and including at least a light emitting component 58, and means for detecting a beam of light passing through the beam receiving passage at least including a light receiving component 60, at least one of the components 58, 60 being electrically connected ultimately to a microprocessor. Upon entry of complementary blades 84 of a plug of an electrically powered device into the receptacle contacts, the beam receiving passage 80 is blocked, thereby breaking transmission of light between the emitter 58 and receiver 60, which is ultimately detected by the microprocessor.

A full N-key rollover capability information entry device includes first and second sets of intersecting light guides oriented at an angle to one another which may comprise a mesh of waveguides that together form a self-supporting planar sheet of a substantially transparent material at the wavelength of light introduced into one end of at least one of the first and second sets of light guides. This permits each intersection to comprise a common portion of both a light guide of the first set and a light guide of the second set that intersect at that intersection. Detection of changes in the intensity of the light in at least one of the sets of light guides in response to key actuation that blocks a portion of the light at a certain intersection is indicative of that actuated key.

A user configurable control device is particularly suitable for household devices such as remote control transmitters. A variety of function control elements in the form of keys are provided to the consumer who selects a desired set of the control elements. Each of the control elements has a unique pattern of projections molded into the bottom surface. These projections are in operative alignment with an array of membrane switches disposed on a switching substrate within the control device. The control device includes a front panel that is perforated with a pattern of slots. Each of the control elements has a pair of projecting tabs that look the element onto the control panel so that it is securely retained thereon, but may be released if desired. The projections on the bottom of the element extend through the slots in the front panel to the switching substrate below. The particular pattern of projections is unique to each control element and the corresponding pattern of switch contacts closed upon actuation of the control element determines the function that is performed.