Designing Of Drainage Pipe Malfunction Testing System

In our country, it is quite serious that drainage pipe walling up and cracking produces pollution and direct or indirect economy loss, so it is very imperative that we will research and design a drainage pipeline automation testing system.Distance measurement by ultrasonic is an effective and noninvasive method, and it can be used in a great variety kinds of fields that need to find range or ascertain location parameters. In recent years, it has been put forward more and more requirement to the accuracy, range, extent and anti-interference of the range-find system, and the technology of ultrasonic range finder is also improving and developing itself gradually. Range finders tend to become intellectualized and miniaturized; it means that they have high precision, reliability, safety and multifunction. The function of the traditional ultrasonic range finders are only limited on distance measure, they cannot meet the need of the modern test system. An ultrasonic range finder is designed in this paper, and several kinds of network interfaces are also developed for the sake of expansion. The range finder could be connected to computers by its network interface and the results of the measurements can be processed and analyzed by the computer; furthermore, the data of the measurements can be shared by the Internet. This will reduce the intensity and improve the efficiency of people's work.A particular introduction of the physical characteristic of the ultrasonic and the principle of the ultrasonic range finder are given in the paper, in addition, the feasibility analysis of using the method of impulse transmission is done also. The microcontroller AT89S52 is chosen to perform as the controller of the system .And the function of each hardware and software module is also described. The direct drive acoustic emitter is composing with Parts of semiconductor. To drive ultrasonic transducer, which has high impedance, the emitter must output high voltage with high current. To design such an emitter, the circuit must have several stages. The design of emitter is base on the character of transducer, especially the impedance of transducer. Before the design of emitter, the character of ultrasonic transducer which can be described by the character of mechanical system must be understood. So do the transistor with high collector-emitter voltage and high collector current. Because of the ultrasonic transistor stages of circuit, it stability can be worse, so the measure of compensation must be designed in the circuit. And still the protection circuit is very important in such a circuit with high voltage and high power.According to the test it is prove that such a direct drive acoustic emitter can convert the signal with low voltage and power to the signal with high voltage and power to drive the ultrasonic transducer directly. The part of ultrasonic receiver can magnify and filter the echo signal, and count the distance by microcontroller.