Light-based proximity detection system and user interface

A light-based proximity sensor, comprising:

• a housing enclosing an interior;
• a light guide mounted in a wall of said housing, comprising:
• an exposed cross-shaped surface in which an elongated vertical section intersects an elongated horizontal section;
• and
• a reflective surface inside said housing;
• an arrangement mounted inside said housing, comprising one or more light emitters and one or more light receivers, arranged so that said light guide causes the one or more light receivers to receive light beams emitted by the one or more light emitters that are reflected, and to not receive light beams emitted by the one or more light emitters that are not reflected;
• and
• a processor mounted in said housing and coupled with said arrangement, for controlling operation of said one or more light emitters and said one or more light receivers, and for calculating a location of a nearby object outside of said housing that reflects light beams exiting said housing back into said housing, based on the reflected light beams received by said one or more light receivers.

A light-based proximity sensor, comprising:

• a housing comprising sides and enclosing an interior;
• a plurality of light emitters mounted in said housing alongside one of said sides, oriented to emit light beams in a direction toward the interior of said housing;
• a plurality of light receivers mounted in said housing alongside the same one side of said housing oriented to receive light beams entering from outside of said housing, the light receivers being closer to the one side than said light emitters so as not to receive light beams emitted by said light emitters that are not reflected;
• at least one reflective surface mounted in said interior and situated farther away from the one side than said light emitters, for redirecting light beams that are emitted by said light emitters to the at least one reflective surface, outward through the one side;
• and
• a processor mounted in said housing and coupled with said light emitters and said light receivers, for controlling operation of said light emitters and said light receivers, and for calculating a location of a nearby object outside of said housing that reflects light beams exiting said housing back into said housing, based on the reflected light beams received by said light receivers.