Digital temperature sensor temperature measurement display system graduation design opening report
(The report includes the significance of the subject, the development situation at home and abroad, the research content of the subject, research methodology, research methods, research tools, research steps, as well as references to the literature.)
1) The significance of the subject
With the rapid development of modern information technology and the gradual realization of the traditional industrial transformation, the ability to work independently of the temperature detection and display system is used in a number of fields, so that the temperature control in the field of production and life has a wide range of applications.
Temperature is a physical quantity most commonly used in daily life, industry, medicine, environmental protection, chemical industry, petroleum and other fields. The basic method of measuring temperature is to use a thermometer to read the temperature directly. The most common tools for measuring temperature are a variety of thermometers, such as: mercury glass thermometers, alcohol thermometers. They often indicate the temperature in the form of a scale, and one must measure the temperature by reading the amount of the scale value. The use of microcontrollers and temperature sensors constitute an electronic intelligent thermometer can directly measure the temperature, the temperature of the digital value, both simple and convenient, intuitive and accurate. This design introduces the digital thermometer compared with the traditional thermometer, with easy to read, wide temperature range, accurate temperature measurement, its output temperature using digital display, mainly for the temperature measurement of more accurate places, or scientific research laboratories, the design of the controller to use the microcontroller AT89S51, the temperature sensor using the DS18B20, the LCD1602 LCD can accurately meet the above The design of the controller uses the microcontroller AT89S51, the temperature sensor uses DS18B20, and the LCD1602 display can accurately meet the above requirements.
2) domestic and international development
The current development of thermometers very quickly, from the original glass thermometer tube thermometer development to the current RTD thermometer, thermocouple thermometers, digital thermometers, electronic thermometers and so on. The main temperature instrumentation, such as thermocouples, RTDs and radiation thermometers have matured technically, but they can only be applied in traditional occasions, can not yet meet the requirements of simple, rapid and accurate temperature measurement, especially in high-tech fields. Therefore, experts in various countries are targeted to compete in the development of a variety of new temperature sensors and special and practical temperature measurement technology, such as the use of fiber optics, laser and remote sensing or storage technology, such as the new thermometer has been practical.
Since 2008, China's digital thermometer and thermostat market has developed rapidly, product output continues to expand, the national industrial policy to encourage electronic thermometers and thermostats industry to high-tech products in the direction of the development of domestic enterprises to invest in new investment projects gradually increased. Investors are paying closer and closer attention to the electronic thermometer and thermostat industry, which makes the development of electronic thermometer and thermostat industry demand increases. This paper studies a microcontroller-based temperature control system to overcome the shortcomings of traditional methods.
3) Research content and methodology
A digital temperature sensor is used as a detection device for single point temperature detection. The LCD1602 liquid crystal is used to directly display the temperature value, and the microcontroller system is used as the control and display system of the electronic thermometer.
The system is considered from the following three aspects:
(1) Detection of the temperature range: 0 ℃ ~ 100 ℃, detection resolution 0.5 ℃.
(2) LCD1602 is used to display the temperature value.
(3) Exceed the warning value (self-defined) to alarm prompt.
The main DS18B20 temperature sensing function is used to detect the current temperature value, the current temperature value is displayed through the LCD, and when the detected temperature value exceeds the set temperature range, the alarm is alerted to achieve the purpose of accurate detection.
The system consists of four main components:
1) sensor data acquisition part of the temperature detection module, if the use of thermistor, to meet the 40 degrees Celsius to 90 degrees Celsius measurement range, but the thermistor accuracy, repeatability, reliability is poor for the detection of 1 degree Celsius signals are not applicable, you can use the intelligent integrated digital temperature sensor DS18B20. DS18B20 is the DALLAS company produced a line of digital temperature sensors, with 3-pin TO-92 small volume package form; temperature measurement range of -55 ℃ ~ +125 ℃, programmable for 9-bit ~ 12-bit A/D conversion accuracy, temperature resolution up to 0.0625 ℃, the measured temperature with symbols to expand the 16-bit digital serial output; its power supply can be both The operating power can be introduced at the remote end, can also be generated using parasitic power supply; multiple DS18B20 can be connected to a line, the CPU only needs a port line to communicate with many DS18B20, taking up less microprocessor ports, saving a lot of leads and logic circuits.
2) The temperature display part can choose LED digital tube display, can also choose LCD liquid crystal display. This module uses LCD1602.
3) Upper and lower limit alarm adjustment module through the key to set the alarm temperature, using the buzzer alarm.
4) microcontroller motherboard part of the intelligent module mainly refers to the microcontroller part, it is mainly to complete the reception of sensor signals and processing work, the design of this module should be the first to do a good job in the selection of microcontrollers, taking into account the performance and cost of the selection of the AT89S52.
The entire system is to work under the control of the AT89S52. The working process is: first of all, the temperature button to set the upper and lower limit temperature range, and then the temperature sensor DS18B20 to collect the current temperature signal, the microcontroller receives this signal, through the processing in the liquid crystal LCD1602 display the current temperature value. If the measured temperature exceeds the set range, the buzzer sends an alarm signal.
In view of this, this graduation design to complete the task objectives are:
(1) the design of the electronic thermometer signal detection part
(2) the design of the electronic thermometer signal processing part
(3) the design of the electronic thermometer main controller part
(4) the design of the electronic thermometer display part and the alarm section
(5) write debugging related software design
(6) the construction of the experimental platform
(7) the whole machine debugging
4) the global sensor future development trend and the 4 important areas (turn)
In recent years, the sensor technology, new principles, new materials and new technologies, the study of a more in-depth, extensive, new varieties, new structures, new applications continue to emerge. Among them, ? Five? Become its development. Important trend.
One is intelligent, two development trajectories go hand in hand. One direction is the integration of a variety of sensing functions and data processing, storage, two-way communication, etc., can be fully or partially realized signal detection, transformation processing, logic judgment, functional calculation, two-way communication, as well as internal self-test, self-calibration, self-compensation, self-diagnostic functions, with low-cost, high-precision information acquisition, data storage and communication, programming automation and functional diversification and other characteristics. Such as the U.S. Linear Technology (LinearTechnology) company's intelligent sensors installed ARM architecture 32-bit processor. Another direction is soft sensing technology, that is, smart sensors combined with artificial intelligence, has emerged a variety of highly intelligent sensors based on fuzzy inference, artificial neural networks, expert systems and other artificial intelligence technologies, and has been utilized in the smart home and other aspects. For example, NEC has developed a new method for implementing simplification of a large number of sensor monitoring? Invariant Analysis Technology? , and has been put into use this year for infrastructure systems.
The second is the mobility, wireless sensor network technology applications to accelerate. The key to wireless sensor network technology is to overcome the node resource constraints (energy supply, computing and communication capabilities, storage space, etc.), and to meet the requirements of sensor network scalability, fault tolerance. The technology was named by the Massachusetts Institute of Technology (MIT) "Technology Review" magazine as the top ten emerging technologies that will have a profound impact on the future life of mankind. At present, R&D focuses mainly on the design of routing protocols, positioning technology, time synchronization technology, data fusion technology, embedded operating system technology, network security technology, energy harvesting technology and other aspects. So far, some developed countries and cities have applied the technology in the fields of smart home, precision agriculture, forestry monitoring, military, intelligent building, intelligent transportation and so on. For example, VoltreePowerLLC, an independent company from MIT, was commissioned by the U.S. Department of Agriculture to set up temperature sensors in the mountains and forests of California, etc., and constructed a sensor network aimed at detecting forest fires and reducing fire losses.
Third, miniaturization, MEMS sensor R & D surged. With the increasing maturity of integrated microelectronic mechanical processing technology, MEMS sensors will be semiconductor processing processes (such as oxidation, lithography, diffusion, deposition and etching, etc.) introduced into the sensor production and manufacturing, to achieve large-scale production, and for the development of the sensor miniaturization provides an important technical support. In recent years, Japan, the United States, the European Union and other semiconductor devices, microsystems and microstructures, speed measurement, microsystems processing methods/equipment, microphone/speaker, level/ranging/gyroscope, photolithography plate-making process and the determination of the nature of the material/analysis of the technical field has made important progress. At present, MEMS sensor technology research and development is mainly in the following directions: (1) miniaturization while reducing power consumption; (2) improve accuracy; (3) realize the integration of MEMS sensors and intelligence; (4) develop new sensors cross-fertilized with optics, biology and other technological fields, such as MOMES sensors (combined with micro-optics), biochemical sensors (combined with biotechnology, electrochemistry) and nanosensors. Combined) and nanosensors (combined with nanotechnology).
Fourth, integration, multi-functional integrated sensors have received widespread attention. Sensor integration includes two categories: one is the integration of multiple sensors of the same type, that is, the same function of multiple sensing elements with integrated process arranged in the same plane, composed of linear sensors (such as CCD image sensors). The other is multi-functional integration, such as several different sensitive components produced on the same silicon chip, made of integrated multi-functional sensors, high integration, small size, easy to achieve compensation and correction, is the main direction of the current development of sensor integration. Such as STMicroelectronics proposed to combine a number of sensors module as a sensor hub to improve product functionality; Toshiba has developed a wafer-level combination of sensors, and released in March this year to be able to simultaneously detect the pulse, ECG, temperature and physical activity and other vital signs of four kinds of information, and will be sent wirelessly to the sensor module such as smart phones or tablet PCs ?Silmee?.
Fifth, diversification, breakthroughs in new materials technology to accelerate the emergence of a variety of new sensors. New sensitive materials is the technical basis of the sensor, materials technology research and development is to enhance performance, reduce costs and technology upgrades. In addition to the traditional semiconductor materials, optical fibers, etc., organic sensitive materials, ceramic materials, superconducting, nano- and biomaterials have become a hot spot for research and development, biosensors, fiber optic sensors, gas sensors, digital sensors, and other new sensors to accelerate the emergence. Such as fiber optic sensors is the use of optical fiber itself sensitive function or the use of optical fiber transmission of light wave sensors, with high sensitivity, strong resistance to electromagnetic interference, corrosion resistance, good insulation, small size, low power consumption, etc., has been applied to the fiber optic sensors can be measured by more than 70 kinds of physical quantities, the development of promising; gas-sensitive sensors can be measured gas concentration is converted into a certain relationship between the power output, with a good stability, good repeatability, good dynamics and good performance. Good stability, good repeatability, good dynamic characteristics, rapid response, easy to use and maintain, etc., the application field is very wide. According to BCCResearch, biosensors and chemical sensors are expected to be the fastest-growing sensor segments, with a CAGR of 9.7% from 2014 to 2019.
Four major areas of concern for the future
With the breakthroughs in cutting-edge technologies in the fields of materials science, nanotechnology, and microelectronics, as well as the needs of economic and social development, four major areas are likely to become the focus of future development of sensor technology.
One is wearable applications. According to the U.S. ABI survey company predicted that in 2017 the number of wearable sensors will reach 160 million. Wearable devices represented by Google Glass are the most popular hardware innovations. Google Glass has up to 10 kinds of built-in sensors, including gyroscope sensors, acceleration sensors, magnetic sensors, linear acceleration sensors, etc., which realizes some functions that cannot be realized by traditional terminals, such as the user only needs to blink his eyes to complete the photo. Currently, the application field of wearable devices is expanding from external watches, glasses, shoes, etc. to broader fields, such as electronic skin. Recently, the University of Tokyo has developed a flexible wearable sensor that can be attached to the skin. The sensor is thin film, the weight per unit area is only 3g/m2, which is about 1/27 of ordinary paper, and the thickness is only 2 microns.
The second is unmanned. The U.S. IHS company pointed out that the application of sensor technology to promote the development of unmanned driver is accelerating the breakthrough. In this field, Google's driverless vehicle project development has achieved important results, through the car installed cameras, radar sensors and laser rangefinders, at intervals of 20 times per second, to generate real-time road information in the area around the car, and the use of artificial intelligence software to analyze and predict the relevant road future movements, while combining with Google Maps to carry out road navigation. Google's driverless cars have already gained the right to exercise on the road in Nevada, Florida and California. Audi, Mercedes-Benz, BMW and Ford and other global automotive giants have launched driverless technology research and development, and some models are close to mass production.
Third, medical care and health monitoring. Numerous medical research organizations at home and abroad, including internationally renowned medical industry giants, have made significant progress in the application of sensor technology in the medical field. For example, Rohm is currently developing an image sensor using near-infrared light (NIR), which is based on the principle of irradiating a near-infrared light LED, using a specialized camera element to capture reflected light, by changing the wavelength of the near-infrared light to obtain an image, and then make blood vessels and so on more distinctly presented through image processing. Some research institutions have made progress in the ability to be embedded or swallowed into the body of the material manufacturing sensors. For example, the Georgia Institute of Technology is developing pressure sensors and wireless communication circuits with embedded sensors in the body, the device consists of conductive metal and insulating film, according to the composition of the **** vibration circuit frequency changes to detect changes in pressure, play a role in the role of the end of the body fluids will be dissolved.
Fourth, industrial control. 2012, GE in the "Industrial Internet: Breaking the Boundaries of Intelligence and Machines" report, through intelligent sensors to connect people and machines, and combined with software and big data analysis, can break through the limitations of the physical and material sciences and will change the way the world operates. The report also points out that by deploying the Industrial Internet in the United States, industries can realize a 1% efficiency improvement, and the energy sector will save 1% of fuel (about $66 billion) within 15 years.In January 2013, GE installed more than 10,000 sensors in a battery manufacturer*** in New York to monitor data such as temperature, energy consumption and air pressure during production, and the plant's managers can use the iPad to access this data to oversee production.
In addition, multinational companies such as Dutch Shell and Fuji Electric have also taken action in this area.
Important Trends in the Development of Sensor Industrialization
In recent years, with the continued deepening of technological research and development, cost reductions, and improved performance and reliability, the typical application market for sensors has grown rapidly, driven by the rapid development of the Internet of Things, mobile Internet, and high-end equipment manufacturing. According to BCCResearch's analysis, the global sensor market is expected to reach $79.5 billion in 2014, and is expected to reach $116.1 billion in 2019, with a compound annual growth rate of up to 7.9%.
The Asia-Pacific region will become the most promising market. At present, the United States, Japan, European countries with advanced sensor technology, upstream and downstream industry supporting mature, is the main producer of medium and high-end sensor products and the largest application market. At the same time, the Asia-Pacific region has become the most promising future market. Interroll Consulting pointed out that the Asia-Pacific region market share will continue to grow in the next few years, is expected to increase to 38.1% in 2016, North America and Western Europe market share will decline slightly.
Transportation and infocommunications are the fastest growing segments of the market. According to Ingenico Consulting predicts that the global automotive sensor scale in 2016 can reach 41.97 billion euros, accounting for 22.8% of the global market; information and communications industry to 2016 can also reach 42.16 billion euros, accounting for 22.9% of the global market, and is likely to become the largest single application market. Medical, environmental monitoring, oil and gas pipelines, smart grids and other areas of innovative applications will become a new hot spot, is expected to create more market demand in the future.
Mergers and acquisitions are increasingly active. The United States, Germany and Japan and other countries of the sensor large-scale enterprise technology research and development foundation is strong, the companies have formed their own technical advantages, the overall market competition pattern has been initially established (attached). It should be noted that large companies through mergers and acquisitions, control of technical standards and patents, in ? High, precise, sharp? sensors and new sensors market gradually formed a monopoly. Under the competitive pressure of large companies, SMEs are moving towards ? Small (in) and refined, small and specialized? The direction of development, the development of proprietary technology, product positioning specific market segments. According to statistics, from July 2010 to September 2011, large-scale mergers and acquisitions in the sensor industry as many as 20 times. Such as the U.S. private equity firm VeritasCapitalIII to $ 500 million in cash acquisition of PerkinElmer lighting and detection solutions (IDS) business; the British Spectrum to $ 475 million acquisition of the U.S. Omega Engineering temperature, measurement equipment manufacturing business. Currently, more and more M&A transactions in emerging market countries.
5) References
[1] Hu Ye, Yao Pengyi. Protel 99 SE circuit design and simulation tutorial. Beijing: Machinery Industry Press, 2005
[2]Qiang Xifu. Sensors [M]. Beijing: Machinery Industry Press, 2004
[3] Kang Huaguang. Fundamentals of electronic technology analog part. Beijing: Higher Education Press, 1998
[4] Kang Huaguang. Fundamentals of electronic technology digital part. Beijing: Higher Education Press, 1998
[5] Liu Shouyi. Microcontroller application technology [M]. Xi'an: Xi'an University of Electronic Science and Technology Press, 2002.
[6] Li Guangdi. Fundamentals of microcontroller. Beijing University of Aeronautics and Astronautics Press, 1994
[7]Sun Huanming. 51 microcontroller C language program application examples in detail. Beijing: Beijing University of Aeronautics and Astronautics Press, 2011
Design Title
Abstract: (content in Song font four)
With the rapid development of modern information technology and the gradual realization of traditional industrial transformation, the temperature automatic detection and display system has been widely used in many fields. People in the temperature detection accuracy, convenient, fast and other aspects have more and more high requirements. The traditional temperature sensor has been unable to meet people's needs, and it is gradually replaced by a new type of temperature sensor.
In this paper, we designed and produced a simple thermometer. This design uses a microcontroller AT89S52 and temperature sensor DS18B20 composed of automatic temperature measurement and control system, according to the actual need to arbitrarily set the temperature value, and automatic control. In this design utilizes the AT89S52 microcontroller as the main control device, DS18B20 as the temperature sensor through the LCD digital tube serial port to transmit data to achieve the temperature display. Through the DS18B20 directly read the measured temperature value, data conversion, can set the temperature upper and lower limits to set the alarm temperature. And after reaching the alarm temperature, the system will automatically alarm.
The design of this paper is from the temperature measurement circuit, the main control circuit, the alarm circuit and so on several aspects to analyze and explain. The device can directly transmit digital signals to the microcontroller, which is convenient for microcontroller processing and control. In addition, the thermometer can also be used directly to measure the temperature using a pyrometer device. This simplifies the data transmission and processing. The advantages of this design are mainly reflected in the operability, simple structural basis, with a large expansion space and so on.
Keywords: microcontroller; temperature sensor; thermometer; alarm
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