Simple principle application of intelligent lighting system

At present, lighting equipment generally adopts two methods: traditional timing control and manual control. These two control methods are inefficient, unreliable, and waste energy. Some places use voice control for lighting facilities. The disadvantage of this method is that any sound can start the lighting facilities. This also causes waste to a certain extent, and also reduces the life of the lamps. When people leave for business, meetings and rest, office lighting will also cause a lot of electricity waste. Intelligent lighting systems can save 40% to 60% of energy in office applications; in large warehouses, it can save 70% of energy. At the same time, the appropriate illumination will also improve the work efficiency of personnel.

1. System composition and working principle

(1) System composition

The system consists of two parts: detection system and control system.

The detection system consists of active and passive pyroelectric infrared detectors and brightness detectors. The brightness detector consists of photoresistors and amplifiers.

The system block diagram is shown in Figure 1.

Figure 1 System composition block diagram.

(2) Working principle

The light brightness detector detects the indoor brightness. If the brightness drops to the set threshold (300 lx), the microcontroller is notified to turn on the infrared detector power. If the passive infrared detector detects a signal of a human entering the room, it is amplified and input into the microcontroller main control circuit. After the microcontroller receives a valid signal, it immediately sends a relay closing signal to connect the lighting circuit and delay the signal for a period of time T. At the same time, the active infrared detector is started to rotate and scan, and the scanning cycle is < T. If the active detector in a certain area detects a human signal within T time, it is amplified and input into the microcontroller, and the microcontroller will trigger the output delay T, so that the relay in the area remains closed and the area remains illuminated. Regardless of whether a person moves, the active detector continuously scans the human signal, the delay is continuously triggered, and the lighting remains. When there is no one in the room, all lights are turned off.

The main program flow of the system is shown in Figure 2.

Figure 2 Main program flow chart.

2. Detection of illumination

Illuminance is the total amount of light or luminous flux falling on a surface per unit area. It is represented by the symbol E. The unit of measurement is lux (1x).

1 1x = 1 lumen/square meter (lm/m2). The illuminance is relative to the location being illuminated, but has nothing to do with the object being illuminated. If one lumen of light is evenly irradiated onto an object of 1 m2, the illuminance is 1 1x.

The illumination detection circuit is shown in Figure 3.

Figure 3 Illumination detection circuit diagram.

The indoor light intensity is detected by using a photoresistor as shown in Figure 3. The threshold of the light intensity is determined by the voltage divider value of R22 and RW7 and sent to the non-inverting input terminal of the comparator LM339. The voltage divider value of the photoresistor is connected to the inverting input terminal of the LM339. When the light intensity gradually decreases, the resistance of the photoresistor increases, and the voltage at the inverting terminal of the input comparator increases accordingly. If it exceeds the set threshold, the comparator outputs a low level to notify the microcontroller.

3. Conclusion

This article proposes the application of intelligent lighting. Although intelligent lighting has not yet been popularized, the research on intelligent lighting technology is already very common. It is believed that with the rapid development of science and technology and the further maturity of lighting technology, the cost of this lighting facility will be reduced and it will have better application value.