　　 The system uses a single-chip microcomputer as a controller to detect the presence or absence of personnel and indoor temperature in the room by using a thermal release human body infrared and temperature sensing system, and designs an intelligent anti-theft fire prevention and lighting control system. The system can alarm in real time according to the temperature in the room to prevent the fire from happening; and according to the light in the room and whether there is someone to control the lighting of the lamp; use the buzzer as the alarm source, if the alarm mode is activated, when the area is detected Someone will send out an alarm signal and start a long beep when the temperature exceeds a certain range. It can achieve intelligent control, energy saving and security purposes, especially for school classrooms, libraries, corridor lighting places.
With the rapid development of the economy and the progress of society, the time for people to travel and work outside is gradually increasing. When the public places such as homes, shopping malls, computer rooms or laboratories are empty, the most worrying issue may be security issues, such as whether There will be thieves breaking into the door, whether it is caused by various power lines due to prolonged use, etc.; and now most of the lights are manually operated by people, especially when we go home in the middle of the night. When the lights are insufficient or the lights are turned on manually when going up the stairs, this will bring us a lot of inconvenience. In addition, the waste of electricity is often caused by the negligence of the staff member who forgets to turn off the equipment after the person leaves. In order to solve the above problems, in the design of the system, consider using the single-chip microcomputer as the main controller, using the pyroelectric body infrared module, the temperature sensing system and the photodiode to detect the presence of indoors and indoors, thereby controlling the indoor lighting. The degree of brightness and darkness, and when the temperature exceeds the alarm and timely alarm, the overall design of an intelligent anti-theft fire and lighting control system, real-time adjustment and control of indoor lighting, so as to achieve intelligent control, energy saving and anti-theft and fire prevention purposes.
1 Principle and design
1.1 System overall design
In the design of this system, the single-chip microcomputer is used as the main controller to detect the presence or absence of personnel and indoor temperature in the room by using the thermal release human body infrared and temperature sensing system. Another intelligent anti-theft fire control system is designed, and the photodiode is used to detect the indoor Light intensity, real-time adjustment and control of indoor lighting, to achieve intelligent control and energy saving purposes.
According to the system design requirements and considering the feasibility of the system, the design block diagram of the whole system is shown in Figure 1. The system takes the single-chip microcomputer as the main controller, and controls the human body sensing module, the temperature collecting module, the photometric collecting module, the light pipe brightness module and the alarm module respectively. The 51 MCU and the pyroelectric body infrared are used to detect whether there is any person in the area. If someone checks whether the illuminance needs light and realizes which position is adjusted, the indicator position is displayed by the indicator light. Finally, the buzzer is used as the alarm source. If the alarm mode is activated, an alarm will be sent when someone detects that it is in the area. When the temperature exceeds a certain range, a long beep will sound.
Figure 1 system block diagram
The basic working principle of the intelligent anti-theft fire prevention and lighting control system is that when the alarm mode is not activated, when a person in the room is detected, the photometric acquisition module is turned on, and the LED lamps of different grades are respectively turned on according to the indoor light intensity; if the indoor temperature is too high, The alarm device will send a second alarm to prevent the fire from happening; when someone enters the room and turn on the alarm device, if the person or the staff can cancel the alarm through an invisible manual reset button, if someone enters the room, the first level alarm will be turned on. And all the LED lights are on, which plays the role of timely alarm and anti-theft.
1.2 system hardware design
The hardware design of the system is divided into five large modules, namely the heat release human body infrared module temperature acquisition module, the photometric acquisition module, the LED light display module and the alarm module.
The hardware design and basic working principle of each module are respectively introduced below.
2 experiment
2.1 Thermal release body infrared module
The human body infrared sensing module circuit is mainly composed of a human body infrared sensor, a Fresnel lens and a special chip BISS0001. When someone appears in its detection zone, the sensor can detect the signal and transmit the signal to the microcontroller. The microcontroller then turns on the device or allows the electrical equipment in the room to be turned on according to the actual situation. In addition, regarding the corridor and the hand-washing lamp, when someone passes by at night, the human body infra-red senses the person to turn on the corridor lamp or the bathroom lamp. The pyroelectric body infrared module circuit is shown in Figure 2.
Figure 2 Thermal release human body infrared circuit diagram
A special thermal infrared chip BISS0001 is used in the circuit. It is a digital-analog hybrid ASIC consisting of an operational amplifier, a voltage comparator, a state control, a delay time timer, and a lock-up timer. The internal circuit is shown in Figure 3. When the infrared radiation radiated by the human body is focused on the detector element of the pyroelectric infrared sensor through the Fresnel lens, the sensor in the circuit will output a voltage signal, and then the signal is first passed through a band pass filter, the upper limit of the filter The cutoff frequency is 16 Hz and the lower cutoff frequency is 0.16 Hz.
Figure 3 BISS0001 chip internal circuit diagram
Because the pyroelectric infrared sensor output detection signal voltage is very weak (usually only about 1 mV), and is a changing signal, and the Fresnel lens makes the output signal voltage pulsed (pulse voltage is 0.1 ~) The voltage signal output from the pyroelectric infrared sensor should be amplified by the operational amplifiers OP1 and OP2 for secondary amplification. After processing by the two-way amplitude detector formed by the voltage comparators COP1 and COP2, the valid trigger signal Vs is detected to start the delay time timer.
The output signal Vo is connected to the single-chip microcomputer for detection. When there is a person, it outputs a high level of 5 V. When the person leaves, after a delay, it is reset to 0 V for the control of the main control circuit. The circuit design puts the chip in a repeatable trigger state to suit the actual situation in the classroom. Repeatedly triggering its working process: In the repeatable trigger mode, when Vc=“1†and A=“1â€, Vs can repeatedly trigger Vo to be in an active state, and can cause Vo to remain valid for a period of Tx. During the Tx time, as long as Vs jumps up, the % will continue to extend from the time of the Vs transition to a Tx period; if Vs remains in the "1" state, then Vo remains active; if Vs remains " In the 0" state, Vo returns to the inactive state after the end of the Tx period, and also during the blocking time Ti, any change in Vs cannot trigger Vo to be in an active state.
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