Knob based gesture system
A knob or joystick apparatus detects gesture based actions of a user's fingers and/or hand. A user grasps the knob or joystick and moves the knob or joystick in either rotational direction, e.g., clockwise or counter clockwise, moves the knob or joystick horizontally/vertically or any combination thereof, and/or presses or pulls the knob or joystick in or out. Capacitive sensors are used in combination with a digital device, e.g., microcontroller, for detecting, decoding and interpreting therefrom various gesturing movements. A user may grasp a knob and either moves his/her fingers in a rotational, horizontal/vertical, and/or in/out movement(s) along an axis of the knob. During the motion(s) of the user's fingers, portions of an outer covering of the knob are deflected inwards toward capacitive sensors, wherein the movement(s) of the deflected portion(s) of the outer covering are detected, decoded and interpretations are made therefrom of various gesturing movements.
1. A gesturing apparatus, comprising:
a base;
a ball rotationally attached to the base;
a shaft having a first end coupled to the ball;
a first target attached at a location of the shaft toward the first end thereof;
a second target attached to and is disposed around the shaft toward a second end thereof;
a first plurality of capacitive sensor elements disposed around the shaft toward to the first end thereof, wherein the first target varies a capacitance of at least one of the capacitive sensors of the first plurality of capacitive sensors depending on a distance between the first target and the at least one of the capacitive sensors; and
a second plurality of capacitive sensor elements disposed around the shaft toward to the second end thereof, wherein the second target varies capacitances of the second plurality of capacitive sensors depending on a distance between the second target and respective capacitive sensors of the second plurality of capacitive sensors,
wherein when the shaft is rotated substantially perpendicular to the base, the first target is proximate to at least one of the first plurality of capacitive sensor elements, wherein the at least one of the first plurality of capacitive sensor elements changes capacitance value that is used in determining rotation position of the shaft, and
wherein when the shaft is tilted away from being substantially perpendicular to the base, the second target is closer to at least one of the second plurality of capacitive sensor elements, wherein the at least one of the second plurality of capacitive sensor elements changes capacitance value that is used in determining tilt position of the shaft;
a third plurality of capacitive sensor elements disposed around the shaft and located between the first and second plurality of capacitive sensor elements; an elastic foam allows motion of the shaft toward or away from the base, wherein the first target is proximate to the third plurality of capacitive sensor elements, wherein the third plurality of capacitive sensor elements changes capacitance value that is used in determining rotation position of the shaft and position toward or away from the base; a knob attached to the second end of the shaft; a control stick attached to the second end of the shaft; a biasing element for biasing the shaft into a perpendicular position, wherein the biasing element is a spring, wherein the knob can be pushed against a force applied by the spring, wherein the control stick can be pushed against a force applied by the spring, wherein ratiometric changes of the capacitance of the first and third capacitive sensor elements determine a vertical position of the first target; a digital processor coupled with the plurality of capacitive sensor elements, wherein the digital processor embedded in a microcontroller comprising an analog front end coupled with the capacitive sensor elements, and wherein the analog front end comprises a capacitance measurement circuit generating a voltage proportional to a measured capacitance, wherein the capacitive measurement unit comprising a capacitive voltage divider.
2. The gesturing apparatus according to claim 1 , wherein the analog front end comprises a charge time measurement unit (CTMU) circuit.
3. The gesturing apparatus according to claim 1 , wherein the analog front end comprises a capacitive sensing module (CSM) circuit.