An example processing system for a capacitive input device includes a first interface coupled to at least one first electrode of at least one lighting element and a second interface coupled to at least one second electrode of the at least one lighting element spaced apart from the at least one first electrode. A controller is configured to: forward-bias the at least one lighting element during first time periods to provide illumination; drive the at least one first and the at least one second electrodes with substantially the same voltage during second time periods; and drive the at least one first electrode with a modulated voltage relative to a reference voltage while guarding the at least one second electrode during third time periods to measure capacitance. A determination module is configured to determine presence of at least one input object in a sensing region based on changes in the capacitance.