Material Detection System Design And Implementation Based On Arm7

According to the explanation of physics, material is the filler of time and space,quality and space is the basic attribute of material. As a kind of existence form,material can be seen everywhere in our daily life. Implying that substances such asfood, clothing, and metal are almost in the form of solid or liquid. For food safety andquality detection almost all over each big media platform, ordinary people’s demandis increasing in this respect. The government regulators also need to be moreconvenient and quick means to meet the demand.Aiming at these problems, this paper puts forward a suitable material detectionequipment for ordinary people and quality inspection personnel at the grass-rootslevel, which is designed for nondestructive, portable, moderate price, easy to use.Understand the various methods of nondestructive material detection through theconsult literature. Through analysis and experiment to seek solution to meet thedesign goals, respectively on the microwave detection and ultrasonic detectionsystem.According to the theory of microwave detecting technology, this paper studies thedielectric properties and microwave detection methods, which focus on free spacemethod is the important research object, and on the basis of the design has realized aoutput frequency sweep microwave signal source. As an important module ofmicrowave detection, the microwave signal source using phase-locked looptechnology, and can be output stability in a wider frequency range.Ultrasonic detection system as the research target, there are two kinds ofdetection methods, reflection and transmission by analyzing its detection theory withtwo detection scheme. Mainly discusses the design and realization of the ultrasonictransmission detection method. This detection system is divided into three modules:power and the control module, the transmitting module，transmission receivingmodule and reflection receiving module. Power and the control module based onARM7in the M2020-N20industrial control board as the control center, with5Vpower supply voltage, which respectively converts by voltage conversion chip to3.3V,±5V and±15V to supply system module. Transmitting module with an emphasis onfrequency synthesis, uses the direct digital frequency synthesis method to generateone way of sine wave, which will be processed by ultrasonic sensor with frequencysweep method. Both of transmission and reflection receiving module include a series of clipping, amplification, rectifier, filter, and then after the AD sampling feedbackback to the control center. Using open source operating system of μC/OS-II tosoftware design. Through the human-computer interaction interface control to switchtasks, so as to achieve the purpose of controlling the whole detection process.Finally detection system based on design of experimental platform structures fora preliminary experiment, controls multi-channel to switch5groups of ultrasonicsensor, covering17~20kHz,21~24kHz,24~27kHz and30.8~34.8kHz and38~42kHz,and launches ultrasonic wave with frequency sweep to detect4kinds of material.Through the analysis of test data, it proved that frequency sweep transmission ofdifferent material have different response curve, which can be the basis for materialqualitative judgment.Exploratory research as a topic in reference on the basis of predecessors’ theory,has preliminary proved the feasibility of the detection system solutions, which haslaid the foundation for further research for the future optimization of materialdetection system.