Contactless touch input system

A proximity sensor, comprising:

• a circuit board;
• a plurality of light emitters mounted on said circuit board;
• a plurality of light detectors mounted on said circuit board;
• two stacked lenses, positioned above said light emitters and said light detectors, comprising an extruded cylindrical lens collimating light along a width of the sensor and a Fresnel lens array collimating light along a length of the sensor, wherein each of said emitters, when activated, projects a light beam through said two stacked lenses along a common projection plane, wherein a reflective object located in the common projection plane above said two stacked lenses reflects light projected at the reflective object from one or more of said emitters to one or more of said detectors, and wherein each emitter-detector pair, comprising one of said emitters and one of said detectors, when synchronously activated, is expected to generate a greater detection signal at the activated detector, when the reflective object is located at a specific 2D location in the common projection plane corresponding to the emitter-detector pair, than when the reflective object is located at any other location in the common projection plane;
• and
• a processor connected to said emitters and to said detectors, sequentially activating each of said emitters and synchronously co-activate one or more of said detectors, and identifying a location of the reflective object in the common projection plane, based on amounts of light detected by the detector of each synchronously activated emitter-detector pair.