Capacitive touch control and display

A capacitive control assembly for use on a solid panel having front and rear surfaces, comprising:

• a plurality (M) of input electrodes disposed about a common center and fabricated upon said panel rear surface;
• the centers of adjacent input electrodes separated from one another by an angle about said common center substantially equal to (360/M) degrees, where M is an integer greater than one;
• a movable electrode positioned adjacent to said panel front surface and rotationally alignable to overlap one portion of at least one of said input electrodes to vary the electrical capacitance between said movable electrode and those of said plurality of input electrodes overlapped by said movable electrode;
• first means for producing a train of pulse signals at a frequency F;
• second means receiving said train of pulses for producing a plurality (M) of square wave outputs each having a frequency (F') equal to (F/N), where N is an integer greater than one, and each successive one of said plurality of square waves having a phase difference of (360/M) degrees with respect to the next preceding and next subsequent square wave;
• each successive square wave output of said second means being coupled to a successive one of said plurality of input electrodes, commencing at a particular one of said input electrodes associated with said reference point;
• third means coupled to said movable electrode for recovering from the plurality of square waves capacitively coupled from said plurality of input electrodes a periodic waveform having a frequency equal to the frequency (F') of said square waves and crossing a predetermined level at a time, after a predetermined transition of the square wave coupled to the input electrode associated with said reference point, linearly related to the angular rotation of said movable electrode with respect to said reference point;
• and
• fourth means coupled to said first and third means for counting the pulses from said first means during the time interval between said predetermined transition and said predetermined level crossing to obtain a digital representation of the angular rotation of said movable electrode with respect to said reference point.