When an array of proximity sensors is used as a keyboard, it can provide an
ambiguous output if a user's finger overlaps several keys or if liquid is spilled
on the keyboard. This ambiguity is reduced by an iterative method that repeatedly
measures a detected signal strength associated with each key, compares all the
measured signal strengths to find a maximum, determines that the key having the
maximum signal strength is the unique user-selected key and then suppresses or
ignores signals from all other keys as long as the signal from the selected key
remains above some nominal threshold value.