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Intelligent classroom lighting control based on infrared sensors

with the development of education, the power consumption of school lighting is increasing. There is a common situation in college classrooms. When a few students are studying by themselves, all the lights are on, causing a lot of waste of electric energy. The management of school lighting power consumption is basically in an extensive management state. The loss of lighting power is increasing. Therefore, it is necessary to develop the automatic control system of classroom lighting. The detection process of raw materials, semi-finished products or finished products before use becomes more and more important

at present, the automatic lighting control devices at home and abroad basically adopt passive human body induction detection, visible light detection, pyroelectric infrared detection, sound detection and other methods, but there are some shortcomings. These methods have some defects in detection, among which pyroelectric infrared detection is the most widely used, but it can not recognize the stationary human body. This paper puts forward a feasible solution to this shortcoming, and designs a set of intelligent classroom lighting control system based on infrared sensor combined with MCU technology

1 scheme design

traditional external sensors are mostly used for the recognition of dynamic human bodies. The infrared sensor intelligent system designed in this paper can not only distinguish the human bodies in motion, but also recognize the relatively static human bodies in the self-study room, so as to achieve the purpose of intelligent control of the classroom lighting system

1.1 system framework design

because the human body will emit infrared rays with a specific wavelength (about 10 LJM), the infrared pyroelectric sensor, which is widely used at present, can be used to identify human signals. After subsequent circuit amplification and a/D conversion, it is transmitted to the control circuit based on a single chip computer to control the switch of lights. Make sure that the light is on when people are walking and the light is off when people are walking. On the contrary, interference signals of equal size cancel each other internally to obtain energy compensation. For the human infrared radiation to the sensor, the pyroelectric sensor focuses the Fresnel lens installed in front and adds it to the two detection elements, so that the sensor generates and outputs voltage signals. The application of Fresnel lens enhances the orthogonality and sensitivity of component recognition

(2) dynamic detection solution of sensor. Pyroelectric infrared sensors are only sensitive to moving human bodies. In many cases, people are in a relatively static or small range of motion state in the classroom, and the sensors usually can not effectively identify. This is also the defect of this kind of products in the current market

the solution proposed in this paper is to solve the problem of dynamic detection from another perspective, that is, let the sensor produce a certain range of motion, and realize the effective recognition of signals through the relative motion between people and sensors. This paper presents two ways of sensor movement

1.3 sensor movement mode

(1) vibration mode. Fix the sensor with a small vibrator. When a person enters the identification area, the sensor detects the human body signal, which is transmitted to the control circuit after processing, so that the vibrator drives the sensor to vibrate together, so as to identify the stationary human body. The vibration time of the system is set to 2 s each time, the vibration cycle is 30 s, and the system is scanned every 30 s. If there is no human signal in this area for two consecutive cycles, the control system will shut down. 2) type inspection shall be carried out when one of the following conditions exists: the action of the lighting lamp

1.4 control circuit design

this design selects lm358 integrated amplifier to amplify and process the signal, which is then transmitted to the control circuit, and 80C51 single chip microcomputer is used to realize programming control. The single chip microcomputer drives two relays to control the lamp and motor respectively

the process is as follows: after the human body signal recognized by the sensor is processed, it is transmitted to the single chip microcomputer, and the single chip microcomputer outputs two instructions. One is to make the relay test product of the control lamp close as a dynamic device, and the lamp is turned on; The other controls the rotation of the small motor. The command is output periodically until the sensor fails to detect the human body signal, the single chip microcomputer controls the two relays to disconnect at the same time, and the lighting lamp goes out, so as to achieve the effect of intelligent control

3 conclusion

this paper uses the pyroelectric sensor and MCU control technology to design the classroom lighting control system, which achieves the effect of power saving, energy saving, convenient operation and humanized control. This design can not only be used in the lighting system of the classroom, but also implement the same control over electric devices such as fans and air conditioners. The system can also be extended to public places such as station waiting rooms and hospitals. When

today vigorously advocates energy conservation, having a good application price means that the replaced detector has a problem value

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