| 摘要 |
PURPOSE:To enable the detection of the number of objects existing in the same direction and the distance to the object with one measurement by receiving and memorizing the required time of receiving a reflected signal from the object within a specified time. CONSTITUTION:As a signal 1 is transmitted from a main control circuit MCC, an ultrasonic transmitter/receiver ULS transmits an ultrasonic wave to objects A-C while a timer PTM starts counting with a CPU. As soon as the ULS receives reflected signals from the nearest object A, the amplified output 3 thereof is compared with a reference value by a comparator circuit COMP to obtain a plurality of square wave signals for the output 4, which is converted into a time range signal 5 via a monostable multivibrator OMC to be applied to the CPU. The CPU takes in the contents of the PTM to determine the distance to the object A to be stored into an RAM. Reflected waves from the objects B and C are received sequentially in a specified time and the same operation is repeated. Thus, based on the contents of the PTM, distances of the respective objects are memorized separately. |
