Apparatus for capturing, aggregating, and transferring data to detect windshield wiper motion in a motor vehicle so as to alert the driver of the need to turn on headlights. The apparatus includes motion-sensing hardware having a microprocessor programmed to detect rhythmic movement of shadows at regular intervals or to receive digitized signals from inertial sensors and to sense rhythmic patterns of vibration or motion in the car and characterize and filter the patterns to accurately distinguish wiper motions from other motions. The software then instructs the microprocessor to output a perceivable alert to the driver indicating that vehicle lights must be turned on.