Patent ID: 7557692

Claim:
A parking sensor apparatus, comprising a microprocessor builds a procedure of avoiding erroneous determinations and the procedure has a first detecting process and a second alternate detecting process; at least two ultrasonic sensors respectively connected to output tem˜inats of the microprocessor through an ultrasonic transducer and connected to input terminals of the microprocessor sequentially through an ultrasonic receiver and an analog to digital converter; and an alarm device connected to outputs of the microprocessor and driven by the microprocessor; wherein the first detecting process comprises steps of: (a1) controlling simultaneously the at least two ultrasonic sensors to respectively transmit an ultrasonic detecting signal through the ultrasonic transducer; (b1) recording a transmitting time of transmitting the ultrasonic detecting signal from the two ultrasonic sensors; (c1) determining whether a reflected ultrasonic detecting signal is received, wherein if a determining result is positive, a transmitting duration of the reflected ultrasonic detecting signal is calculated according to the transmitting time, and then a distance between the ultrasonic sensor and an obstacle is further calculated according to the transmitting duration, but if the determining result is negative, return to the step (a1); and (d1) determining whether the obstacle exists according to a calculating result of the step (c1), wherein if a determining result of this step is positive, the second alternate detecting process is executed, but if a determining result of this step is negative, return to the step (a1).