A method for detecting an object on a sensor sensitive to capacitive coupling comprises simultaneously transmitting signals on at least two electrodes of the sensor, wherein at least one of the signals transmitted on each of the at least two electrodes has a frequency that is different from a frequency of at least one other signal transmitted on another electrode of the at least two electrodes, sampling a signal on at least one other electrode crossing the at least two electrodes, wherein the signal is responsive to capacitive coupling formed between the at least two electrodes and the at least one other crossing electrode, and detecting at least one object from the sampled signals.