INTERFERENCE PREVENTION METHOD IN OBJECT DETECTION DEVICE

PURPOSE:To prevent malfunction caused by ultrasonic pulses from other object detection devices, relating to an object detection device that transmits ultrasonic pulses and receives the pulse reflected from the object such as obstacles. CONSTITUTION:In an object detection device 1, ultrasonic pulses are, at a constant pulse rate set by a generating period setting means 7, transmitted by an ultrasonic pulse transmission means 3, and if ultrasonic pulses which are reflection of the ultrasonic pulses from obstacles, etc., or those from other object detection device are received by a reception means 4, the object detection device 1 transmits ultrasonic pulses at a modified pulse rate, and a detection signal control means 6 measures the time period from transmission of a ultrasonic pulse of the modified rate till reception of reflected ultrasonic pulses and the time when the reception means receives the above first ultrasonic pulse. These two times are compared with each other by a comparison means 9, an if agreement is found, detection signal representing presence of obstacles, etc., is outputted, otherwise, on detection signal is outputted by assuming them the ultrasonic pulses from other object detection devices.