精选优质文档-倾情为你奉上Design of ultrasonic wave guide device Abstract: This article recommends a device of ultrasonic wave guide which is designed to adopt AT89C51 single-chip microprocessor computer as controller and apply the principle of ultrasonic distance measuring. The device can detect the distance between the blind and an obstruction in the road ahead and convert the message to a sound reminder .According to frequency variation of the reminding sound, it will enable the blind to judge whet
