Priority and combination suppression techniques (PST/CST) for a capacitive keyboard
Apparatus and methods are described for selecting which of a plurality of simultaneously activated keys in a keyboard based on an array of capacitive sensors is a key intended for selection by a user. Combinations of keys which are commonly activated simultaneously when a user intends to select a single key are identified and associated with the single keys most likely to give rise to the identified combinations during normal use of the keyboard. In use, an observed combination of simultaneously activated keys is compared with predefined combinations of keys corresponding to those identified as being commonly activated simultaneously. If the combination of activated keys matches one of the predefined combinations, the most likely intended key associated with the matched one of the predefined combination of keys is taken to be most likely intended key.
1. An apparatus comprising:
a touch-sensitive interface that comprises a plurality of sensing areas within a sensing region; and
one or more computer-readable non-transitory storage media coupled to the touch-sensitive interface that embody logic operable when executed to:
receive a first set of signals, the first set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of the plurality of sensing areas within the sensing region of the touch-sensitive interface; and
select, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings do not constitute one of a plurality of predefined combinations of one or more of the sensing areas, each predefined combination having a preselected sensing area of the plurality of sensing areas, one of the sensing areas corresponding to the substantially contemporaneous capacitive couplings based at least in part on scaled output signals of the first set of signals, wherein each of the output signals is scaled by a predetermined scale factor associated with a priority rank of the one of the plurality of sensing areas corresponding to the substantially contemporaneous capacitive coupling to which the output signal corresponds.
2. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises sensing areas beyond sensing areas neighboring the preselected sensing area of the particular predefined combination.
3. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises four sensing areas.
4. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises three sensing areas arranged along a line and the preselected sensing area for the particular predefined combination is a middle one of the three sensing areas along the line.
5. The apparatus of claim 4 , wherein the line corresponds with a direction of approach or extent of a pointing object during normal use.
6. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises four sensing areas arranged along a line and the preselected sensing area for the particular predefined combination is located at an end of the line.
7. The apparatus of claim 6 , wherein the line corresponds with a direction of approach or extent of a pointing object during normal use, and the preselected sensing area for the particular predefined combination is a second most distant one of the four sensing areas along the line relative to the direction of approach or extent of the pointing object during normal use.
8. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises a contiguous series of neighboring sensing areas.
9. The apparatus of claim 1 , wherein a particular predefined combination of the plurality of predefined combinations comprises at least three sensing areas.
10. The apparatus of claim 1 , the logic further operable when executed to:
receive a second set of signals, the second set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of the plurality of sensing areas within the sensing region of the touch-sensitive interface; and
select, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings constitute a particular predefined combination of the plurality of predefined combinations, the preselected sensing area of the particular predefined combination.
11. A method comprising:
receiving a first set of signals, the first set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of a plurality of sensing areas within a sensing region of a touch-sensitive interface; and
selecting, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings do not constitute one of a plurality of predefined combinations of one or more of the sensing areas, each predefined combination having a preselected sensing area of the plurality of sensing areas, one of the sensing areas corresponding to the substantially contemporaneous capacitive couplings based at least in part on scaled output signals of the first set of signals, wherein each of the output signals is scaled by a predetermined scale factor associated with a priority rank of the one of the plurality of sensing areas corresponding to the substantially contemporaneous capacitive coupling to which the output signal corresponds.
12. The method of claim 11 , wherein a particular predefined combination of the plurality of predefined combinations comprises sensing areas beyond sensing areas neighboring the preselected sensing area of the particular predefined combination.
13. The method of claim 11 , wherein a particular predefined combination of the plurality of predefined combinations comprises a contiguous series of neighboring sensing areas.
14. The method of claim 11 , wherein a particular predefined combination of the plurality of predefined combinations comprises three sensing areas arranged along a line and the preselected sensing area for the particular predefined combination is a middle one of the three sensing areas along the line.
15. The method of claim 14 , wherein the line corresponds with a direction of approach or extent of a pointing object during normal use.
16. The method of claim 11 , further comprising:
receiving a second set of signals, the second set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of a plurality of sensing areas within a sensing region of a touch-sensitive interface; and
selecting, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings constitute a particular predefined combination of a plurality of predefined combinations of one or more of the sensing areas, each predefined combination having a preselected sensing area, the preselected sensing area of the particular predefined combination.
17. A computer-readable non-transitory storage media embodying logic that is operable when executed to:
receive a first set of signals, the first set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of a plurality of sensing areas within a sensing region of a touch-sensitive interface; and
select, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings do not constitute one of a plurality of predefined combinations of one or more of the sensing areas, each predefined combination having a preselected sensing area, one of the sensing areas corresponding to the substantially contemporaneous capacitive couplings based at least in part on scaled output signals of the first set of signals, wherein each of the output signals is scaled by a predetermined scale factor associated with a priority rank of the one of the plurality of sensing areas corresponding to the substantially contemporaneous capacitive coupling to which the output signal corresponds.
18. The media of claim 17 , wherein a particular predefined combination of the plurality of predefined combinations comprises sensing areas beyond sensing areas neighboring the preselected sensing area of the particular predefined combination.
19. The media of claim 17 , wherein a particular predefined combination of the plurality of predefined combinations comprises a contiguous series of neighboring sensing areas.
20. The media of claim 17 , wherein a particular predefined combination of the plurality of predefined combinations comprises three sensing areas arranged along a line and the preselected sensing area for the particular predefined combination is a middle one of the three sensing areas along the line.
21. The media of claim 20 , wherein the line corresponds with a direction of approach or extent of a pointing object during normal use.
22. The media of claim 17 , the logic further operable when executed to:
receive a second set of signals, the second set of signals comprising two or more output signals responsive to two or more substantially contemporaneous capacitive couplings, each of the substantially contemporaneous capacitive couplings occurring between a pointing object and one of the plurality of sensing areas within the sensing region of the touch-sensitive interface; and
select, when the sensing areas corresponding to the substantially contemporaneous capacitive couplings constitute a particular predefined combination of a plurality of predefined combinations of one or more of the sensing areas, each predefined combination having a preselected sensing area, the preselected sensing area of the particular predefined combination.