Proximity sensor and controller

A proximity sensor comprising:

• one or more detection electrodes to be capacitively coupled to an object located in proximity to the one or more detection electrodes;
• a contact electrode to be in contact with the object;
• an excitation circuit that is connected to either one of the one or more detection electrodes or the contact electrode to supply an excitation voltage to the electrode to which the excitation circuit is connected;
• a detection circuit that is connected to either one of the one or more detection electrodes or the contact electrode, whichever the excitation circuit is not connected to, the detection circuit being operable to, based on a detection voltage at the electrode connected to the detection circuit, generate a detection signal in response to a first electrostatic capacitance between the one of the one or more detection electrodes and the object;
• and
• a ground electrode between the one or more detection electrodes and the contact electrode and shared by the excitation circuit and the detection circuit;
• wherein
• the detection circuit is operable to generate the detection signal in response to the first electrostatic capacitance, which is smaller than a second electrostatic capacitance between the contact electrode and the object, the detection signal indicating a degree of proximity of the object to the one of the one or more detection electrodes, the object being in contact with the contact electrode;
• and
• the contact electrode has a larger area than the one or more detection electrodes such that a connection capacitance of the contact electrode is larger than a detection capacitance of the one or more detection electrodes.