Installation and selection of infrared induction switch

Infrared induction switch is a kind of induction switch, which mainly realizes the switching function by sensing the temperature of human body. Let's introduce the infrared induction switch in depth.

Brief introduction of infrared induction switch

The full name of infrared induction switch is pyroelectric infrared induction switch. Any object in nature will always emit infrared radiation as long as its temperature is higher than absolute zero (-273℃). The higher the temperature of the object, the smaller the peak wavelength of infrared radiation and the greater the energy emitted. When a person enters the sensing range, the pyroelectric infrared sensor detects the change of the infrared spectrum of the human body and automatically switches on the load. If the person does not leave the sensing range, it will continue to open. After people leave, the load will automatically turn off after a delay.

The main device of infrared induction switch is pyroelectric infrared sensor. The human body has a certain temperature, usually 36-37 degrees, so it will emit infrared rays with a specific wavelength. 9.5um infrared rays emitted by human body are enhanced by Fresnel lens and concentrated on infrared induction light source. Pyroelectric infrared sensors are usually used as infrared sensors. When the temperature of receiving infrared radiation from human body changes, the charge balance will be lost.

The charge is released outward, and the subsequent circuit can trigger the switch action after detection and processing. Working principle of infrared induction switch

Infrared sensor switch is an automatic control switch based on passive infrared sensor technology. The main sensor is human thermal discharge infrared sensor. The body temperature is usually 37 degrees,

It will emit infrared rays with a wavelength of about 10 micron, and the temperature around the human body is generally lower than 37 degrees, which is higher than the infrared radiation wavelength of the human body. The pyroelectric infrared sensor works by detecting the change of infrared radiation in the area. Thermoelectric infrared sensor includes two thermoelectric elements connected in series or in parallel. Pyroelectric elements are very sensitive to infrared radiation with the wavelength range of 0.2 ~ 20μ m, and the polarization directions of the two elements are opposite in structure to suppress the interference caused by their own temperature rise. Therefore, the uniform environmental background infrared radiation has the same effect on the two pyroelectric elements, the discharge effect is cancelled, and the sensor has no signal output; Similarly, when the human body is still in the sensing range, the discharge effect is a constant value after cancellation, and the sensor has no signal output; Only when the human body moves within the sensing range, the infrared radiation received by the two elements is different and constantly changing, and the sensor outputs the sensing signal.

After circuit amplification, the control purpose is realized. The direct detection distance of pyroelectric infrared sensor is very close, and its directivity is poor. An alternating "visible area" and "blind area" are generated in front of the probe through the Fresnel lens, so that when the human body moves in front, the sensor will receive intense infrared radiation, which can obviously increase the detection distance, and can also specify the detection range and monitoring field of view as needed. The infrared sensing switch based on pyroelectric infrared sensing technology itself does not emit any kind of radiation, so the power consumption is very small. Under the control of daytime lighting, the switch is in the off state. At night, someone enters the sensing range, the sensor detects the movement and change of human infrared spectrum, and the switch automatically turns on the light. If this person doesn't leave, this switch will always be on. After people leave, the switch will automatically turn off the lights after a delay. There are generally 86 panels and top-mounted installation forms.

It is an ideal choice for modern architecture and home. Disadvantages of infrared induction switch: it is easily interfered by various heat sources, light sources, radio frequency radiation and hot air flow; Passive infrared penetration is poor, and human infrared radiation is easily blocked; When the ambient temperature is close to the human body temperature, the detection and sensitivity are obviously decreased, and sometimes short-term failure occurs.

Installation of infrared induction switch

Infrared pyroelectric human body sensor is generally installed indoors, and its false alarm rate is closely related to the installation location and mode. Proper installation shall meet the following conditions:

1, the top-mounted infrared induction switch should not be too high from the ground, preferably about 2.5-3 meters. The wall-mounted panel switch can be installed in the original switch position and replaced directly.

2, away from heating, air conditioning, refrigerators, stoves and other places where temperature changes are sensitive.

3. There shall be no screens, furniture, large bonsai or other partitions within the detection range.

4. Don't look straight out of the window, so as to avoid the disturbance of hot air flow outside the window and the false alarm caused by people walking.

5. Do not install doors, air ducts and other places with strong airflow activities.

Selection of infrared induction switch

If it is corridor lighting control, acousto-optic control delay switch or infrared induction switch can be selected according to the actual situation. If you choose infrared induction switch, you should pay attention to the following issues:

1. Select concealed wall mounting or top mounting. If possible, it is recommended to choose top loading, which has wide detection range and reliable product work. It is easy to achieve high power by controlling power, but because most buildings have no zero line, the performance of wall switches is limited and the working reliability is reduced.

2. Control incandescent bulbs or energy-saving fluorescent lamps, or led lamps. This is very important. General overhead induction switch can control any load. Because the 86-panel induction switch has no zero line, ordinary models can control incandescent lamps, and special models can control energy-saving lamps/fluorescent lamps, but can't control LED lamps (can't be completely turned off). The inductive switch controlling the LED lamp must have a zero line.

3. Control the number and power of loads. Because the starting current of energy-saving lamps is relatively large, the number of loads should generally not exceed two, and incandescent lamps should generally not exceed three. Or negotiate with the manufacturer to take additional measures.

4. Is there a fire emergency control terminal, especially is the panel emergency control mandatory, that is, is the normal lighting fire line powered off when the emergency fire line is powered on?

Selection of infrared induction switch

If it is corridor lighting control, acousto-optic control delay switch or infrared induction switch can be selected according to the actual situation. If you choose infrared induction switch, you should pay attention to the following issues:

1. Select concealed wall mounting or top mounting. If possible, it is recommended to choose top loading, which has wide detection range and reliable product work. It is easy to achieve high power by controlling power, but because most buildings have no zero line, the performance of wall switches is limited and the working reliability is reduced.

2. Control incandescent bulbs or energy-saving fluorescent lamps, or led lamps. This is very important. General overhead induction switch can control any load. Because the 86-panel induction switch has no zero line, ordinary models can control incandescent lamps, and special models can control energy-saving lamps/fluorescent lamps, but can't control LED lamps (can't be completely turned off). The inductive switch controlling the LED lamp must have a zero line.

3. Control the number and power of loads. Because the starting current of energy-saving lamps is relatively large, the number of loads should generally not exceed two, and incandescent lamps should generally not exceed three. Or negotiate with the manufacturer to take additional measures.

4. Is there a fire emergency control terminal, especially is the panel emergency control mandatory, that is, is the normal lighting fire line powered off when the emergency fire line is powered on?