Work principle of sensor lights
Lighting Ideas
By Author | 21 August 2021 | 1 Comments
How does sensor lights work?

How does sensor lights work?

At present, there are four kinds of induction lights widely used in various family life scenes:

1.Infrared sensor light
2.Touch sensor light
3.Voice control sensor light
4.Dusk to dawn light bulbs

Here is how they work:

1. The working principle of infrared sensor light

The main component of infrared induction is the human body pyroelectric infrared sensor.

As we all know, the human body has a constant body temperature, generally around 37 degrees.So it emits infrared rays with a specific wavelength of about 10 um. The passive infrared probe detects the infrared rays emitted by the human body at about 10 um to work. The infrared rays of about 10 um emitted by the human body are enhanced by the Fresnel lens filter.Then collected on the infrared sensor source.

Infrared induction sources usually use pyroelectric elements, which lose charge balance when the temperature of the infrared radiation of the human body changes, and discharge charges outward. The subsequent circuit can trigger the switch after the detection and processing.

When a person enters the sensing range of the switch
Step1.the dedicated sensor detects the change in the infrared spectrum of the human body
Step2.the switch automatically turns on the load

If the person does not leave the sensing range, the switch will continue to be turned on.There is no action after the person leaves or in the sensing area, and the switch is delayed (Time adjustable TIME: 5-120 seconds) automatically turn off the load.The infrared sensor switch has an induction angle of 120 degrees, a distance of 7-10 meters, and an adjustable delay time.

radar sensor lights

2. Working principle of touch sensor light

The principle of the touch sensor lamp is to form a control loop with the electronic touch IC installed inside and the electrode sheet at the touch point of the lamp.

When the human body touches the sensing electrode sheet, the touch signal is transmitted to the touch sensor terminal by pulsed direct current. Then the touch sensor terminal will send a trigger pulse signal to control the light to turn on; if you touch it again, the touch signal A pulse signal is generated by the pulsating direct current and sent to the touch sensor. At this time, the touch sensor will stop sending the trigger pulse signal. When the alternating current crosses zero, the light naturally goes out.

However, sometimes after a power failure or unstable voltage, it will light up by itself. If you touch a paper or cloth with excellent signal sensitivity, it can also be controlled.

3. The working principle of voice-activated induction light

motion sensor night light

Sound is produced by vibration, and sound waves propagate in the air. If it encounters a solid, it will propagate this vibration to the solid. The sound control element is this kind of material that is sensitive to vibration. When there is a sound, it is turned on (the resistance becomes smaller), and when there is no sound, it is turned off (the resistance becomes very large). Then through the circuit and the chip to make a delay, the circuit can be turned on for a period of time when there is sound.

4. Working principle of Dusk to dawn lights bulbs

dusk to dawn light bulbs
The light sensor module first detects the intensity of the light and decides whether to stand by and lock each module of the LED infrared sensor light.

There are two situations:
1. In the daytime or when the light is strong, the light sensor module locks the infrared sensor module and the delay switch module according to the sensor value.

2. At night or when the light is relatively dark, the light sensor module puts the infrared sensor module and the delay switch module in a standby state according to the sensor value.

If a human body moves within the sensing range of the lamp, the infrared sensor module will start and detect a signal, and the signal triggers the delay switch module to turn on the LED infrared sensor light. If a person continues to move within its range, the LED human body sensor light will always be on. When the person leaves its range, there is no infrared sensor signal, and the delay switch automatically turns off the LED infrared sensor light within the time set value. Each module returns to the standby state and waits for the next cycle.

The above content is the working principle of various induction lights, I hope to help you.

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