Infrared sensor combines with LED lamps
Infrared sensor is to detect the infrared launched from human body. The main principle is: the human body emitting about 10um infrared. Through the Fresnel filter lens, it enhanced to the pyroelectric element PIR. When the activities of the infrared radiation launch position will change, the component will lose the charge balance. An infrared sensor (PIR) converts the infrared radiation energy through the Fresnel filter lens into an electrical signal, i.e., thermoelectric conversion. In the passive infrared detector detection area without human movement, the infrared sensor is only the background temperature. When the human body into the detection area through the Fresnel lens, pyroelectric infrared sensor is the human body temperature and background temperature difference. The signal is collected and the system has been found in the detection data to determine whether it is really someone and other infrared sources into the detection area.
Passive infrared sensors have three key components: Fresnel filter lens, pyroelectric infrared sensor (PIR) and matching low noise amplifier. Fresnel lens has two roles: First, the role of focusing, that is, the pyroelectric infrared signal refraction on the PIR: Second, the detection area is divided into a number of Ming and dark areas, so that the detection area into the moving object (person) and can be in the form of temperature changes in the PIR to produce changes in the pyroelectric infrared signal. Generally, the low-noise amplifier is matched. When the ambient temperature on the detector rises, especially close to the body's normal body temperature (37 ° C), the sensitivity of the sensor decreases and the gain is compensated to increase its sensitivity. The output signal can be used to drive the electronic switch, and to achieve LED lighting circuit switching control.
An E27 standard screw cap lamp, its power supply is AC180V-250V (50 / 60Hz), with infrared sensor detection range of about 3M-15M, and its standard product IFS-Bulb3W lamps up to 80lm, 5W lamps up to 140lm. The Infrared sensor is embedded in the center of the LED light source module. Once the infrared sensor detects the human body temperature, the LED light bulb will automatically turn on and off within 50 seconds. It’s suitable for any kind of indoor applications such as corridors, storage rooms, stairs and entrance hall.
Ultrasonic sensor, which is similar with infrared sensors, gets more applications in the automatic detection of moving objects in recent years. Ultrasonic sensor mainly uses the Doppler principle, through the crystal outward launch more than the human perception of high-frequency ultrasound, the general selection of 25 ~ 40kHz wave, and then control the module to detect the frequency of the reflected wave. If the region has object movement, reflection Wave frequency will have a slight fluctuations, that is, the Doppler effect, in order to determine the object area of ??the lighting movement, so as to achieve the purpose of control switch.
Ultrasonic oscillation characteristics, can be in the gas, liquid and solid propagation and its propagation speed is different; it also has refraction and reflection phenomenon. Low frequency in the air, with faster attenuation. And in the solid, the liquid, its attenuated less, spread far. Ultrasonic sensors are using these features of ultrasound. Ultrasonic sensors have a wide range of sensitive areas, no visual blind area, free from obstructions and other characteristics, the technology has been used in the field of business and security for more than 25 years, has been proved to be the most effective way to detect small objects. So the system of LED lamps can be combined with sensitive control switch.
As the high sensitivity of ultrasonic sensor, the movement at air vibration, ventilation and heating system and the surrounding space around will cause false triggering of ultrasonic sensor, so the ultrasonic sensor needs to be calibrated in time.