Design of intelligent lighting control system based on single chip microcomputer

　　0 Preface

　　Natural resources are various substances and energies in nature that can be used by humans. They are the basis for human production activities and life, the material guarantee and material basis for human survival and development, and the cornerstone of sustainable development of human society. With the continuous development and updating of technology, humans are developing and utilizing natural resources more and more, but the number of natural resources is limited, and the regeneration capacity of renewable resources is far behind the utilization speed. In this historical period, the depletion speed of natural resources has created history. However, in the real society, people seem to have not yet realized the crisis that energy will bring to society and the earth. The phenomenon of energy waste is very common, and a large amount of energy consumption is wasted in vain, which not only wastes resources but also pollutes the environment.

　　The phenomenon of energy waste is very obvious in lighting. The power consumption of lighting systems in many public places such as school classrooms, libraries, reading rooms, factories, office buildings, subways, etc., which require long-term lighting, is astonishing. In these lighting systems with high power consumption, the normal use of some electricity is indispensable, but the unnecessary waste of electricity caused by factors such as the lack of responsibility of users and managers, poor environmental awareness, and lack of scientific lighting control systems is inevitably distressing. For example, at night when no one is indoors, the lighting is still on. The long-burning lights in the equipment area consume an astonishing amount of electricity in a year. Many areas with sufficient light intensity during the day are also always on. This phenomenon has caused a lot of unnecessary energy waste and unnecessary economic losses.

　　According to relevant statistics, if the public teaching building of Beijing University of Science and Technology turns on the lights for one less hour every day, it can save 150,000 kW·h of electricity every year, which is about 100,000 yuan. It can be seen that energy-saving control on the lighting system is very necessary. However, how to ensure the actual lighting needs without increasing the workload of management personnel, ensure the lighting quality, and realize automatic intelligent control, so as to achieve energy-saving control system. What kind of way can be developed is an urgent problem that needs to be solved in front of us. This paper uses infrared thermoelectric sensors through the data control function of the single-chip microcomputer to realize the system to automatically judge the number of people in a certain area, so as to automatically control the lighting brightness. The control system is an effective means to solve this problem. Through the collection, judgment and control of the sensor data collected by the single-chip microcomputer, the energy-saving control lighting system is realized, the lighting brightness in the area is guaranteed, and the purpose of effective energy saving is achieved under the goal of ensuring the actual use effect. The application of single-chip microcomputer in lighting energy-saving control system not only has good economic benefits, but also has excellent social benefits, and also has a profound impact on environmental protection and sustainable development.

　　1 Overall structure and working principle of energy-saving control system

　　In order to meet the lighting requirements of people in a certain area, save ineffective energy loss, and thus achieve energy conservation, the energy-saving control system collects environmental data through photosensitive elements, namely infrared thermoelectric sensors or human body sensors. When the photosensitive element detects that the natural light reaches a predetermined value, this value is considered that the current natural light has met the lighting requirements of users in the area, so there is no need to start the lighting equipment. When the photosensitive element detects the value set for the natural light area, it indicates that the natural light is insufficient and supplementary lighting is required. At this time, the human body sensing device or pyroelectric sensor installed in the area begins to collect human body sensing signals, and the lighting equipment in the corresponding area is connected and started. After the person leaves, if the human body sensing device or pyroelectric sensor cannot collect human body sensing signals within a certain period of time, it is considered that there is no person in the area and no light is needed, then the lighting equipment is interrupted and turned off. Experiments have found that when pyroelectric sensors detect human body signals, they usually have higher detection accuracy for moving human body signals, while the detection accuracy of stationary human body signal sensors is poor.

　　People in a certain area, such as those in classrooms or libraries who need light, are usually stationary. Therefore, in order to prevent the sensor from sending wrong signals to the lighting equipment when the person is stationary, causing the lighting to be turned off, an infrared counter-radiation counting device is added when designing the energy-saving control system to detect the number of people in the area, and judge whether the people in the area have actually left by the number of people. The dual detection method greatly improves the accuracy of human detection and the scientificity and reliability of the intelligent control energy-saving system, thereby achieving the purpose of truly intelligently controlling the lighting system and saving energy.

　　Figure 1 shows the overall structure of the energy-saving control system.

　　2 Overall effectiveness of energy-saving control systems

　　The lighting energy-saving controller in the area realizes automatic intelligent control and adjustment of the lighting tube system in the area through the internal program of the single-chip microcomputer. From the perspective of the functional effect of the entire system, the input parameters of the system are mainly characteristic information equivalents such as human presence signals in the area, ambient temperature and humidity, and light intensity. That is: when the presence of a person is detected in the area, combined with external factors such as ambient temperature and humidity, ambient light, etc., it dynamically determines whether to turn on the lighting system and the energy-saving matching scheme of lighting fixtures.

　　When the ambient light meets the lighting specification requirements in the area, the lamps will be controlled not to turn on. That is, only when there are learners in the area and the external ambient light intensity parameters reach below a certain threshold condition, the internal calculation, analysis and judgment will be made to reasonably adjust the lighting fixtures to turn on the matching plan, so as to achieve efficient, stable and energy-saving operation of the lighting in the area. In order to achieve efficient and energy-saving lighting system in the area while being flexible to control without wasting extra manpower and material resources, the system uses a single-chip microcomputer as the core controller of the control system, and is assisted by hardware systems such as human body sensing devices or pyroelectric sensors, infrared counter-radiation counting devices, and photosensitive element detection devices to ensure the reliability and accuracy of the control system. Combined with the actual regional data collected by various sensors, combined with hardware to realize signal transmission and controller analysis and processing, the energy-saving control system can realize automatic and intelligent energy-saving control of the local lighting system.

　　3 Design of energy-saving control system

　　The design uses pyroelectric sensor as an integrated module for light detection and pyroelectric signal processing circuit. The module includes PIR pyroelectric sensor, veneer lens and signal integrated processing chip. The sensing distance of the pyroelectric sensor module can reach 7 m and the sensing angle can reach 110° when the veneer lens is added. Because the signal amplitude output by the pyroelectric sensor is small (less than 1 mV), it cannot be received by the microcontroller, let alone directly used to drive the lighting system, so its output signal must pass through a signal processing circuit to convert the output signal into a digital signal suitable for microcontroller processing. As an integrated processing chip, BISS0001 has high-performance signal processing capabilities and highly integrated chips. It contains components such as operational amplifiers, timers, state controllers, and voltage comparators. The integrated chip can form a passive pyroelectric infrared delay switch with pyroelectric sensors and infrared sensors.

　　The main idea of ​​the system software design is to double-detect the data of the infrared counter and the pyroelectric sensor, correct the data collection errors and mistakes between each other, and complete the delay control function. The main program flow is shown in Figure 2.

　　When there is no human body sensing signal at the detection position of a pyroelectric sensor, the system cannot determine whether there is a person at that location. At this time, the infrared tube counting device is required to conduct a second confirmation of the person at that location. If there is an error in the infrared tube counting device, for example, the error is 1 person, then the main program must assume that it can only return to the main program to continue monitoring when the number of people at that location is greater than 1 [3]. When the main program detects that the number of people has increased, after a delay of 20 seconds, the pyroelectric sensor detects the location of the person, and then sends a signal to the lighting device to turn on the lighting at that location, thereby turning on the lighting device and keeping the lighting devices at other locations unchanged.

　　4 Conclusion

　　The lighting energy-saving control system uses single-chip microcomputers, pyroelectric sensors, infrared counter-counting devices and other hardware devices to ensure that the lighting needs of people in a certain area are met without increasing the workload of management personnel, realizing intelligent control of the lighting system, saving energy to the greatest extent, and realizing intelligent energy-saving control. Practice has proved that this control system has good economic and social .