The disclosed apparatus may include a capacitive proximity sensor that increases capacitance in response to proximity of an object; a reference capacitor in parallel with the capacitive proximity sensor; a switch that connects and disconnects the capacitive proximity sensor and the reference capacitor; and a capacitance sensing block that generates a capacitance signal based on a capacitance of the reference capacitor when the switch is in a disconnecting state and based on the capacitance of the reference capacitor and a capacitance of the capacitive proximity sensor when the switch is in a connecting state. Various other methods and systems are also disclosed.