Since the discovery of infrared, infrared technology has been constantly innovating and widely used in our life. The Internet of things is constantly mentioned with the progress of Internet technology. Smart home is the embodiment of the Internet of things under the influence of the Internet. What is smart home? Smart home connects various devices in the home through Internet of things technology, and provides a variety of functions and means such as home appliance control, lighting control, telephone remote control, indoor and outdoor remote control, anti-theft alarm, environmental monitoring, HVAC control, infrared forwarding and programmable timing control. Infrared transmission technology is widely used in smart home control system because of its mature technology, good stability, strong privacy and relatively low cost.
Infrared transmission technology is a technology that uses infrared as a carrier for data transmission. In daily life, infrared transmission technology can be seen everywhere. The most typical is that household appliances such as TV and air conditioner are controlled by infrared remote controller. With the progress of science and technology and the continuous improvement of people’s living standards, people have higher and higher requirements for intelligent home, such as lighting control, background music, security alarm and so on.
Infrared transmission technology features: 1. Good stability: using analog transmission mode, not digital signal transmission, so there is almost no similar signal to interfere with it. 2. 2. Strong privacy: due to the short wavelength of infrared and poor diffraction ability to obstacles, it is suitable for short-range wireless communication. Because of this, infrared transmission has strong privacy. For example, when we use infrared remote control in our own home, the electrical appliances of our neighbors will not be affected by the control. Therefore, the selection of infrared penetrating PC materials will be given priority in the selection of remote control. 3. Low cost: infrared transmission technology is very mature, and the upstream and downstream industrial chain is also very developed. It has obvious advantages in cost compared with wireless transmission technologies such as Bluetooth and WiFi.
The smart home system integrates audio and video equipment, lighting system, curtain control, air conditioning control, security system, digital cinema system, video server, video cabinet system and network appliances by using audio and video technology, automatic control technology, generic cabling technology, Internet technology, security technology and communication technology to realize unified management and intelligent control. In this integrated system, infrared transmission technology plays a variety of roles and plays an important carrier role in the whole information transmission.
Infrared remote control has been used in people’s daily life for many years. The traditional infrared remote controller is generally used to control a single electrical appliance. For example, the TV is controlled by the TV remote controller and the air conditioner is controlled by the air conditioner remote controller. Most people’s families have two, three or even more remote controllers. However, with the emergence of smart home control system, we don’t need so many remote controls. We only need a remote control to control all electrical equipment at home.
Using generic cabling technology and relevant communication protocols, all lamps, curtains, various household appliances and alarm equipment in the home can be integrated into a unified system, and then operated through the remote control or control panel. In addition, it can also cooperate with the situational function of the smart home system to control multiple devices at the same time with the simplest operation. For example, when you come home from work, you only need to pick up the infrared remote control and click “night mode”, you can automatically close the curtains, turn on the living room lights, turn on the TV, air conditioning and stereo, and set the home alarm equipment to the owner’s home mode to prevent false alarm. In this way, the tedious operation of electrical appliances and equipment one by one is saved, and a good mood can be gained by gently pressing the remote control.
Infrared detection technology is divided into active infrared detection and passive infrared detection, which have different application modes in smart home. Active infrared detection is to send one or more modulated parallel infrared beams through the infrared transmitter, which are received by the infrared receiver, converted into digital signals and sent to the alarm controller. If there are obstacles in the transmission section, the alarm will be triggered. Active infrared detection is widely used in the home alarm system. For example, infrared transmitters and receivers are installed at both ends of the balcony. As long as someone crosses the balcony, the alarm signal will be triggered immediately, so that the owner can be on alert at the first time.
The passive infrared detector judges whether there is someone in the area through the infrared energy change of the corresponding area by the infrared thermal release sensor. Due to the difference between the infrared energy of the human body and the environment, when people pass through the detection area, the detector senses the change of infrared energy, and will provide feedback signal to the system. Combined with the linkage function of smart home, the function of people coming to light up and people walking to light out can be realized. For example, a passive infrared detector is installed on the top of the door of the bathroom. When the owner gets up at night and enters the bathroom, the light will turn on automatically, and when he leaves the bathroom, the light will turn off automatically, which is convenient and can save electricity.
As a wireless communication technology, infrared transmission can also be applied to data transmission between household appliances, such as audio transmission. Rambler, the leading manufacturer of multimedia speakers in China, released an infrared power amplifier ramble in 2008. Because it adopts infrared transmission mode and does not need data cable, it can be installed at any position indoors, such as wall or ceiling, which is quite convenient, and will not affect the beauty of indoor decoration because of the wire exposed on the wall.
The penetration of infrared itself is not strong. If it is applied to smart home, its penetration performance must be improved. A polycarbonate material reylon (Ruilong) that can penetrate infrared ray developed by the leading manufacturer of modified materials in China. The material is particularly suitable for making windows of infrared sensors by injection molding or extrusion molding. The material has the characteristics of high near-infrared penetration efficiency (800nm-1200nm transmittance greater than 80%) and high visible light shielding efficiency (250-750nm transmittance less than 0.5%). More importantly, the initial transmission wavelength of the material is greater than 750nm, which is much greater than other similar products. Because the signal propagation frequency of the current infrared sensor is usually near 920nm, reylon series materials can more effectively shield the interference of the band radiation near 920nm.