Hc-Sr501 Rd-624 Human Infrared Sensor Electronic Module Sensor Pyroelectric Probe Inductive Switch

• Function Type: Mixing System, Infrared Range and Communication System
• Detection Type: Heat Detectors
• Output Signal Type: Switching Transducer
• Model NO.: HC-SR501 RD-624
• Material: Mixture
• Customized: Customized
• Usage: Vibration Sensor
• Type: Vibration Sensor
• Output: Switching Transducer
• Theory: Ultrasonic Sensor
• Model Number: Hc-Sr501
• Transport Package: PP Bag
• Origin: China
• Production Capacity: 100000

Product Description

Perfect version hc-sr501 is an automatic control module based on infrared technology. It adopts the original imported probe design, with high sensitivity, strong reliability and ultra-low voltage working mode. It is widely used in all kinds of automatic induction electrical equipment, especially the automatic control products powered by dry battery.
Basic knowledge of pyroelectric sensor and common problems in application
Pyroelectric infrared sensor is a kind of sensor which can detect infrared emitted by human or animal and output electric signal. As early as 1938, it was proposed to use pyroelectric effect to detect infrared radiation, but it was not paid attention to. It was not until the 1960s that the rapid development of laser and infrared technology promoted the research on pyroelectric effect and the application of pyroelectric crystals. Pyroelectric crystal has been widely used in infrared spectrometer, infrared remote sensing and thermal radiation detector. It can be used as an ideal detector for infrared laser. It is widely used in various automatic control devices. In addition to the well-known corridor automatic switch and anti-theft alarm, it has a good application prospect in more fields. For example: in the room when no one will automatically stop the air conditioner, water dispenser. The TV set can judge whether no one is watching or the audience has gone to bed and automatically shut down. Turn on the application on the monitor or automatic doorbell. Combined with camera or digital camera, it can automatically record the activities of animals or people and so on. You can develop more excellent new products according to your own ideas and other circuits. Or automatic control device.
Basic knowledge of pyroelectric sensors
Pyroelectric effect, similar to piezoelectric effect, refers to the phenomenon that the surface of crystal is charged due to the change of temperature. Pyroelectric sensors are sensitive to temperature. It is composed of ceramic oxide or piezoelectric crystal elements. Electrodes are made on the two surfaces of the elements. When the temperature changes Δ T within the monitoring range of the sensor, the pyroelectric effect will produce a charge Δ Q on the two electrodes, that is, a weak voltage Δ V between the two electrodes. Because of its high output impedance, there is a FET in the sensor for impedance transformation. The charge Δ Q produced by pyroelectric effect will be combined by the ions in the air and disappear, that is, when the ambient temperature is stable, Δ t = 0, the sensor has no output. When the human body enters the detection area, there is Δ t output due to the difference between the human body temperature and the ambient temperature; if the human body does not move after entering the detection area, the temperature does not change and the sensor does not output. So this kind of sensor detects the movement of human body or animal. The experimental results show that the detection distance of the sensor is less than 2m without optical lens (also called Fresnel lens), and the detection distance can be more than 7m with optical lens.
Attention should be paid to the following points in use:
1, The DC working voltage must meet our requirements. Too high or too low will affect the performance of the module, and the power supply must be well regulated and filtered. For example, the USB power supply of the computer, the power supply of the mobile phone charger, and the older 9V stacked battery can not meet the working requirements of the module. It is recommended that the customer use the power supply of the transformer and pass through the 22 after the three terminal regulator chip 0uf and 0.1uF capacitor power supply after filtering.
2, When debugging, the human body should stay away from the sensing area as far as possible. Sometimes, although the human body is not directly in front of the module, when the human body is too close to the module, the module can sense the output all the time, and when debugging, the human body should not touch the circuit part, which will also affect the work of the module. A more scientific way is to connect the output end with an LED or multimeter, cover the module with a newspaper, and leave the module Two rooms, wait for 2 minutes to see if the module has output all the time?
3, The module can work normally when it is not connected to the load, and work disorderly when it is connected to the load. One reason is that the power capacity of the power supply is very small, the load consumes more power, and the voltage fluctuation caused by the load working causes the module misoperation. The other reason is that the load will produce interference when it is powered on. For example, the relay or electromagnet and other inductive loads will produce reverse electromotive force, and the 315m transmitter board will produce negative electromotive force when it is working Electromagnetic radiation will affect the module. The solution is as follows: A. add inductance filter to the power supply. B. The load and module use different voltages, for example, the load uses 24 V working voltage, the module uses 12 V working voltage, and the three terminal voltage regulator is used to isolate them. C: Use a higher capacity power supply.
4, The human body sensing module can only work indoors, and the working environment should avoid direct sunlight and strong lights. If the working environment has strong RF interference, shielding measures can be adopted. In case of strong airflow interference, close doors and windows or prevent convection. Avoid being blown by the wind and other objects.
5, The human body sensing module is recommended to be installed in a sealed box, otherwise there may be an output signal all the time.
6, If the detection angle of the human body sensing module is less than 90 degrees, opaque adhesive tape can be used to cover the lens or cut the lens to reduce it.
7, Dual probe is used in the human body sensing module. The movement direction of human hands, feet and head is closely related to the sensing sensitivity. Moreover, the characteristics of the infrared module determine that the sensing distance cannot be accurately controlled.
8, The probe (PIR) in the module can be soldered on the other side of the circuit board. The probe can also be extended with double core shielding wire, and the length should be less than 20 cm.

Functional features:
1. Full automatic induction: when someone enters the room