Changing the detection range of a touch sensor
In one embodiment, a controller includes a storage unit and a processor unit. The processor unit is coupled to the storage unit and configured to receive a signal associated with an operation of a device that includes a touch sensor. The touch sensor includes a first plurality of electrodes oriented in a first direction in a first portion of the touch sensor, a second plurality of electrodes oriented in the first direction in a second portion of the touch sensor, and a third plurality of electrodes intersecting the first and second plurality of electrodes. The processor unit is further configured to determine, in response to the signal, that a detection mode of the touch sensor is to be changed and in response to the determination, couple the second plurality of electrodes to a fixed voltage source to decrease a detection range in the second portion of the touch sensor.
1. A device comprising:
a touch sensor configured to operate in a detection mode and including a first plurality of electrodes oriented in a first direction in a first portion of the touch sensor, a second plurality of electrodes oriented in the first direction in a second portion of the touch sensor, and a third plurality of electrodes intersecting the first and second plurality of electrodes;
a storage unit; and
a processor unit coupled to the storage unit and configured to:
determine that a detection mode of the touch sensor is to be changed;
in response to determining that the detection mode of the touch sensor is to be changed, (i) couple the second plurality of electrodes to a fixed voltage source to decrease a detection range in the second portion of the touch sensor, wherein a decrease in the detection range decreases the projection of electrical field lines from the touch sensor and (ii) couple the first and the third plurality of electrodes to at least an input and an output of one amplifier respectively to drive the first and the third plurality of electrodes such that intersections between the first and third electrodes are equipotential to increase a detection range in the first portion of the touch sensor, wherein an increase in the detection range increases the projection of electrical field lines from the touch sensor;
and
initiate, in response to a detected change in capacitance of the touch sensor, an action of the device while continuing an operation of the device, the action comprising discarding reporting of one or more subsequent touches of the touch sensor detected while continuing the operation of the device.
2. The device of claim 1 , wherein the operation is a call.
3. The device of claim 1 , wherein the fixed voltage source is one from the set comprising: a ground connector; and a power supply of a microcontroller.
4. The device of claim 1 , wherein the second portion comprises a first area along a first edge of the touch sensor and a second area along a second edge of the touch sensor.
5. A method comprising:
(a) performing a call operation in a device having a touch sensor;
(b) operating the touch sensor in a detection mode, the touch sensor including a first plurality of electrodes oriented in a first direction in a first portion of the touch sensor, a second plurality of electrodes oriented in the first direction in a second portion of the touch sensor, and a third plurality of electrodes intersecting the first and second plurality of electrodes;
(c) determining that a detection mode of the touch sensor is to be changed;
(d) coupling electrodes in response to determining that the detection mode of the touch sensor is to be changed including:
(i) coupling the second plurality of electrodes to a fixed voltage source to decrease a detection range in the second portion of the touch sensor, wherein a decrease in the detection range decreases the projection of electrical field lines from the touch sensor, in response to determining that the detection mode of the touch sensor is to be changed, and
(ii) coupling the first and the third plurality of electrodes to at least an input and an output of one amplifier respectively to drive the first and the third plurality of electrodes such that intersections between the first and third electrodes are equipotential to increase a detection range in the first portion of the touch sensor, wherein an increase in the detection range increases the projection of electrical field lines from the touch sensor; and
(e) initiating, in response to a detected change in capacitance of the touch sensor an action of the device while continuing the call operation of the device, the action comprising discarding reporting of one or more subsequent touches of the touch sensor detected while continuing the call operation of the device.