This invention proposes a proximity sensor that can be integrated with a fluorescent lamp ballast. The sensor measures disturbances in the electric field between two electrodes mounted in the lamp cover. The sensor's output voltage deviates from zero as the occupant approaches the center of the lamp, enabling fine-grain occupancy measurements in spaces without requiring a motion or thermal signature. There are two detection schemes: one uses dimmed sensing to dim the lamp ballasts, the other uses sparse sensing to take advantage of the wide angle of detection of the sensors, requiring fewer lamp sensors. The electronics do not contribute significantly to the noise floor of the lamp sensor. The output sensitivity is affected by electrode spacing, depth and bulb power.