An electron-emitting device contains an emitter resistor layer patterned into multiple laterally separated sections situated between the electron-emissive elements, on one hand, and emitter electrodes, on the other hand. The first and second conductors may have sidewalls with conductive barriers. The output network is arranged on a printed circuit board. Azimuthal spatial transform filtering is applied to produce data representing a received acoustic pulse of the selected azimuthal borehole mode. A sensor that detects voluntary motion of the handicapped individual is connected to a transducer that converts the motion detected into a computer input, such as a mouse \u201cclick,\u201d which selects the active area on the menu. In some embodiments, a plate is attached to one end of a light rod and supports the light rod in the cover in a cantilever fashion or in combination with other support.