How to choose the right detector
Fodder Cutter,Chaff Cutter,Chaff Cutter Machine,Mini Chaff Cutter Hunan Xinta Machinery Manufacturing Co., Ltd. , https://www.china-agricultural-product.com
Infrared detector: Any object will irradiate strong and weak infrared rays due to the difference in surface heat. Due to the difference in objects, there are also differences in the wavelength of infrared radiation. Infrared detection is mainly used to detect the human body and some other intrusive moving objects. When the human body enters the detection area, stable and constant thermal radiation is destroyed, resulting in a change of thermal radiation. After receiving the infrared sensor, it is amplified, processed and sent an alarm signal.
Microwave object movement detector: Doppler frequency shift of high-frequency radio waves is used as a detection method, suitable for open spaces or squares. A microwave is a very high-frequency radio wave. It has a short wavelength and is easily reflected by an object. According to the frequency drift of the incident wave and the reflected wave, an intruding object can be detected.
Infrared microwave detector: It is one of the commonly used equipment in the alarm system. Its price is generally between 200~1600 yuan. Its working principle combines infrared and microwave in one. When the infrared and microwave detectors have alarm signals at the same time, the probe will have alarm output, which reduces the possibility of false alarms. There are many models of infrared microwave probes, corresponding to different detection distances, some detecting a fan-shaped area, some detecting a narrow and long section (such as a corridor), and some are 360-degree detection. It is necessary to select a suitable model according to specific needs, so that Achieve the desired effect. The sensitivity of the detector is generally adjustable.
Magnetic sensor: It is a widely used, low cost, easy to install, and does not need to adjust and repair the detector. Magnetic switch is divided into movable parts and output parts. The movable parts are installed on the movable doors and windows; the output parts are installed on the corresponding doors and windows, and the installation distance between the two is not more than 10mm. There are two lines on the output part, the normal state is the normally closed output, the door and window are opened more than 10mm, and the output conversion becomes normally open. 
Glass break detector: It uses a piezoelectric microphone mounted on the position facing the glass. Because only the high-frequency glass breakage sound is effectively detected, it will not be affected by the vibration of the glass itself.
Ultrasonic object movement detector: The ultrasonic object movement sensor needs a transducer capable of transmitting ultrasonic waves and another receiving signal, and a receiving and transmitting transducer coexist in one body. The transmitter for normal transmission emits a fixed-frequency ultrasonic wave and spreads across the detected space. If there is an object reflected ultrasonic wave, its frequency will shift, thereby detecting whether there is an object moving. The detector is susceptible to vibration and air flow.
Infrared Detector: A detector that uses beam interception to trigger an alarm when someone traverses the surveillance zone and interrupts the invisible infrared beam. Commonly used for outdoor wall alarms, it is always used in pairs: one for transmission and one for reception. The transmitter emits one or more infrared light that cannot be seen by the human eye to form a cordon. When an object passes through, the light is blocked, the receiver signal changes, and the alarm is amplified after processing. Infrared on the radio probe to choose the appropriate response time: too short and easy to cause unnecessary interference, such as small birds flying over, small animals through, etc.; too long will miss a report. The shortest shading time is usually determined at a speed of 10 meters per second. If the person's width is 20 centimeters, the shortest interruption time is 20 milliseconds. More than 20 milliseconds alarm, less than 20 milliseconds no alarm.
Smoke alarm detectors: There are two types of photoelectric detectors: the photoelectric type and the ion type. The former uses smoke to block the light path to send an alarm. The latter uses its own sensor to sense the concentration of ions in the air. Different sensors sense different gases (such as gas). It is a smoke detector that detects carbon ion concentration for fire protection.