At present, most of the lighting systems of colleges and universities in China are controlled by timing methods, such as a large amount of waste of electrical energy and inflexible lighting modes. Based on 51 single-chip microcomputers, this paper sets the lighting state according to the different needs of the teaching building and dormitory by setting time, sensing illumination and sound, and realizes the intelligent dynamic control of the lighting system. The test results show that the system can change the lighting state under different conditions, adapt to the needs of different places, and achieve the purpose of intelligent control.
In today's fast-growing economy, the large consumption of electric energy has made it a scarce resource. How to save energy and reduce consumption has become a hot spot in lighting system research in recent years. At present, most of the lighting systems of colleges and universities in China are controlled by timing. Although the control is simple and easy to implement, there are many problems at the same time: when the traffic is small at night, all the lamps will be lit, which will cause a large amount of waste of electric energy; In addition, the timing lighting mode can not flexibly adjust the working state of the lighting system, especially in thunderstorms and haze weather, posing a safety hazard. The intelligent lighting control system designed in this paper can set the lighting mode and lighting time according to the different functional requirements of different areas of the school, and realize the dynamic intelligent management of the lighting system.
1 system hardware module
The design of this system is based on 51 series single-chip microcomputer, which consists of 7 hardware modules, which are control, timing, light control, voice control, button, display and illumination. The light control and sound control module realizes the collection and judgment of external light and sound signals; the lighting time control of the lighting system is realized regularly; the control module adopts STC89C52 single chip microcomputer, controls the lighting circuit according to external light, sound and timing signals, and switches different working states. To adapt to external needs. The lighting system architecture is shown in Figure 1.
1.1 Control Module
This article uses STC89C52 microcontroller, with 8-bit CPU and in-system programmable Flash, is a low-power, high-performance microcontroller. In the design of this paper, the control module receives the time of the timing module and the light and sound signals of the external environment. By judging the lighting level and controlling the working state of the lighting, the intelligent dynamic management of the lighting system is realized.
1.2 input module
1.2.1 Timing module
The timing module uses the DS1302 chip to provide date and time information to the entire system. It not only has low power consumption, high performance, but also has a power-down time function, and it will not stop timing even when the microcontroller is powered off. At the same time, it is also convenient for the system to judge whether the set night time is currently reached.
1.2.2 Light Control Module
The light control module uses a photoresistor to collect the optical signal, and uses the LM393 comparator to determine the optical signal strength. Figure 2 shows the light control circuit. The non-inverting input and the inverting input of the comparator are connected with a potentiometer. When there is no natural light, the potentiometer is adjusted to keep the potentials of the two inputs consistent. At this time, the comparator will output low power. Flat signal. When the photoresistor is illuminated by natural light, its resistance is greatly reduced, so that the potential of the non-inverting input of the comparator rises and the comparator outputs a high level signal. Through the comparator output signal to the P1.4 port of the single-chip microcomputer, the single-chip microcomputer can judge whether the external light intensity reaches the threshold intensity, thereby controlling the change of the working state of the lighting module.
1.2.3 voice control module
In the voice control module, an electret microphone (instead of R6 resistor in Fig. 3) is used to collect the acoustic signal, which is a kind of condenser microphone with high sensitivity. The sound signal strength is judged by LM393, the principle is the same as the light control circuit, and the final signal is output to the P1.3 port of the single chip microcomputer, as shown in Fig. 3.
1.3 output module
1.3.1 Display Module
As shown in Figure 4, the display circuit uses the LCD1602 liquid crystal to display the current date and time. The LCD1602 liquid crystal can display two lines of 16 characters each. The added potentiometer can adjust the contrast of the LCD screen at any time.
1.3.2 Lighting module
As shown in Figure 4, the lighting module simulates three working states of the lighting with 2 rows of 8 LED lights: off, interval bright and full light. When the work is off or fully illuminated, all 8 LED lights are turned off or on; when the interval is required to be lit, the 2 rows of LED lights are illuminated in 1 row, providing relatively low intensity illumination.
2 system software design
The intelligent lighting system combines time, illumination and sound to judge the changes of the external environment, and sets three working states for the lighting to provide different illumination intensities, namely full light, interval bright and extinguished. The system running process is shown in Figure 5.
In the working state control of the lighting, the setting time of the dormitory is from 18:00 to 6:00 the next day, and the setting time of the teaching building is from 18:00 to 24:00, which is called the night mode, and the lighting is set within the set time. Work in a spaced-apart state to provide basic nighttime illumination. If the intensity of the sound intensity collected by the voice control module is greater than the threshold intensity, the flow rate of the teaching building or dormitory is large, the lighting module will switch to the full light state, provide high-intensity illumination, and after the sound signal disappears, After a delay of 5 s, the working condition of the interval is restored to ensure the lighting demand for nighttime activities.
Outside the set time, if there is thunderstorm or smog weather, the lighting system collects and judges the natural light intensity of the outside world, even if it is not in night mode, it needs certain illumination. Therefore, when the light intensity of the light control module is less than At the threshold intensity, the lighting module will work in a spaced-apart state to ensure the basic lighting of the teaching building or dormitory; then by collecting and judging the sound signal, if the traffic is large, the lighting module will switch to full brightness again. status.
3 system test
According to the functional requirements of the system, the working state of the system in all cases (preset set time is 18:00 ~ 6:00) is tested. The test circuit is shown in Figure 6.
When the set time, light intensity threshold is not reached, the LED light is off;
When the set time, light intensity "threshold value, sound intensity" threshold value is not reached, the LED lights are spaced apart;
When the set time, light intensity "threshold value, sound intensity" threshold is not reached, the LED light is fully illuminated;
When the set time and sound intensity "threshold value" are reached, the LED lights are spaced apart;
When the set time, sound intensity threshold is reached, the LED light is fully illuminated.
It can be seen that the system switches the working state according to requirements under various conditions and meets the design requirements.
4 Conclusion
According to the lighting needs of colleges and universities and the dormitory, the intelligent lighting system can adaptively adjust the working state of the lighting system according to the setting time and the changes of ambient light and sound, and realize the dynamic management of the lighting system. The system can also be applied to lighting in public places, featuring low cost, convenient operation and easy expansion of functions, thereby maximally saving power and energy.
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