Patent ID: 8259533

Claim:
A processor-implemented method for determining an ultrasonic detecting cycle of an ultrasonic sensing device including an ultrasonic transducer, the method comprising steps of: setting an initial detecting cycle T; generating a first sensing wave by the ultrasonic transducer; calculating a first time-of-flight value corresponding to the first sensing wave; generating a second sensing wave by the ultrasonic transducer after the first sensing wave has been generated for the initial detecting cycle T; calculating a second time-of-flight value corresponding to the second sensing wave; comparing the second time-of-flight value with the first time-of-flight value, wherein if a difference between the second time-of-flight value and the first time-of-flight value is smaller than a threshold value, the initial detecting cycle T is determined as the ultrasonic detecting cycle, wherein if the difference between the second time-of-flight value and the first time-of-flight value is greater than the threshold value, the initial detecting cycle T is adjusted for generating a third emitting signal; and using the ultrasonic detecting cycle to periodically generate a plurality of sensing waves for discriminating whether a foreign object enters a sensing range.