Abstract: A method to notify a third party if a child is left behind in a vehicle includes securing a motion detector system within a vehicle, the motion detector being secured to a roof of an inner cabin of the vehicle and directed to a rear seat; detecting via the motion detector if a child is left behind in the rear seat after the vehicle is locked and after a driver exits; if the child is left behind, activating an air conditioner via a computer system operably associated with the motion detector; after activating the air conditioner, detecting if the driver has returned to the vehicle; if the driver has not returned, activating a car alarm via the computer system; after activating the car alarm for a predetermined time, determining if the driver has returned; and if the driver has not returned, notifying a third party via a transceiver operably associated with computer system.