brief introduction of PIR sensor(passive infrared sensor)
The infrared sensor is developed according to the principle of infrared reflection, which belongs to an intelligent water-saving and energy-saving equipment. Including induction faucet, automatic hand dryer, medical hand washer, automatic soap feeder, induction urinal flushing device and induction toilet.
This is the standard name, also known as passive infrared sensor。
PIR sensor principle
This is based on the principle of infrared reflection. When the human hand or part of the body is in the infrared region, the infrared emitted by the infrared transmitting tube is reflected to the infrared receiving tube due to the shielding of the human hand or body, and the signal processed by the microcomputer in the integrated circuit is sent to the pulse solenoid valve, After receiving the signal, the solenoid valve opens the valve core according to the specified command to control the water outlet of the head. When the human hand or body leaves the infrared sensing range, the solenoid valve does not receive the signal, and the solenoid valve spool is reset through the internal spring to control the water shutoff
Infrared sensor
In the spectrum, the wavelength from 0.76 to 400 microns is called infrared, which is invisible light. All substances above absolute zero (- 273.15 ℃) can produce infrared rays. Modern physics calls it thermal radiation. Medical infrared can be divided into two categories: near infrared and far infrared.
Solar spectrum
Infrared ray is one of the many invisible rays of the sun. It was discovered by German scientist hoxler in 1800. It is also called infrared thermal radiation. He decomposes the sunlight with a prism and places a thermometer on the color band of various colors to try to measure the heating effect of light of various colors. It was found that the thermometer on the outside of the red light warmed up the fastest. Therefore, it is concluded that there must be invisible light outside the red light in the solar spectrum, which is infrared. It can also be used as a transmission medium. The wavelength of infrared in the solar spectrum is greater than that of visible light, and the wavelength is 0.75 ~ 1000 μ m。 Infrared can be divided into three parts, namely near infrared, with wavelengths of (0.75-1) ~ (2.5-3) μ M; Medium infrared, wavelength (2.5-3) ～ (25-40) μ M; Far infrared, wavelength (25-40) ~ 1000 μ M.
The real infrared night vision instrument is photomultiplier tube imaging, which is completely different from the principle of telescope. It can not be used during the day. It is expensive and needs power to work.
Near infrared or short wave infrared, with a wavelength of 0.76 ~ 1.5 μ m, penetrates deeply into human tissue, about 5 ~ 10 mm; Far infrared or long wave infrared, with a wavelength of 1.5 ~ 400 microns, is mostly absorbed by the surface skin, and the depth of penetrating the tissue is less than 2 mm.
Classification of infrared sensors:
By technology
Ultrasonic sensor - temperature sensor - humidity sensor - gas sensor - gas alarm - pressure sensor - acceleration sensor - ultraviolet sensor - magnetic sensor - magnetoresistive sensor - image sensor - electric quantity sensor - displacement sensor
By application
Pressure sensor - temperature and humidity sensor - temperature sensor - flow sensor - liquid level sensor - Ultrasonic Sensor - immersion sensor - illumination sensor - differential pressure transmitter - acceleration sensor - displacement sensor - load cell
System classification
1. Inclination sensor
Inclination sensors are widely used in military, aerospace, industrial automation, engineering machinery, railway locomotives, consumer electronics, marine ships and other fields. Whig company provides the most comprehensive and professional product solutions and services for domestic users in the world. Provide more than 500 kinds of tilt sensors with servo, electrolyte, capacitance, inductance, optical fiber and other principles.
Acceleration sensor (linear and angular acceleration)
It is divided into low-frequency high-precision force balance servo type, low-frequency low-cost thermal convection type and medium and high-frequency capacitive acceleration displacement sensor. The total frequency response range is from DC to 3000hz. Applications include automotive motion control, automotive testing, home appliances, game products, office automation, GPS, PDA, mobile phones, vibration detection, construction instruments and experimental equipment.
2. Infrared temperature sensor
It is widely used in household appliances (microwave oven, air conditioner, range hood, hair dryer, toaster, induction cooker, frying pan, heater, etc.), medical / household thermometer, construction industry, office automation, portable non-contact infrared temperature sensor, industrial field temperature measuring instrument, power automation, etc. It can not only provide sensors, modules or complete temperature measuring instruments, but FBelec also provide a package of solutions including optical lens, ASIC and algorithm according to users' needs
