infrared sensor is usually a 3 pin metal package, the pins are supply-side (internal switch D pole, DRAIN), signal output (internal switch S pole, SOURCE), ground (GROUND) .
Pyroelectric infrared sensors are the main working parameters
Voltage (commonly used pyroelectric infrared sensor operating voltage range 3 ~ 15V)
Wavelength (typically 7.5 ~ 14 μ m)
Source voltage (usually 0.4 ~ 1.1V, R = 47kΩ) Output signal voltage (typically greater than 2.0V)
Note the use of infrared modules:
1, the human body are highly sensitive sensor device module, its high power requirements, the regulator must be a good filter, such as cascading 9V battery may not work because of the larger resistance, advises clients to use the LM7808 regulator chip 0.1UF regulator and then through the 220UF capacitor filtered supply.
2, the module does not work properly when connected load, after load connected to the work of disorder, because the power capacity of a small load is power, work load due to voltage fluctuations lead to the module malfunction, the other reason is that the load may cause interference with electrical work, such as relays or solenoids and other inductive load will produce back EMF, 315M will be launching board work will affect the electromagnetic radiation module. Solution is as follows: A, power supply filter inductor increases. B, by using different load and voltage of the module, for example: load with 24V operating voltage, 12V voltage module, during which three-terminal regulator with the LM7812 isolation. C: with a larger capacity power supply. 3, the body work environment sensor module should avoid sunlight, direct exposure to bright light, if the work environment has a strong radio frequency interference shielding measures can be used. In case of strong flow interference, close doors and windows or to prevent convection. Sensitive area to avoid facing the heating appliances and objects, and debris easily by the wind and clothing
4, the human sensor module must be assembled in a sealed box, otherwise the output signal has been there. Sensor (PIR) and the lens has a focusing distance, usually 20-30mm range of adjustment.
5, infrared detectors to detect if the required angle of less than 90 degrees, you can block the lens with opaque tape or cut narrow the lens to achieve.
6, the human body sensor module using a dual probe, the body's limbs and head movement direction and the sensor sensitivity are closely linked, if you set the improper installation, will affect the induced effects.
7, module probe (PIR) for assembly and welding the other side of the circuit board. Probe can also be extended with the dual-core shielded cable, 2 meters length should be as well.
Conclusion
Pyroelectric infrared sensor has low price, technical performance and stability, development using simple
One such feature, in addition to the above monitoring alarm and automatic switching of typical applications, in many of its
It has wide application areas, such as automatic starting or stopping the air conditioner, water dispenser, TV, automatic
Camera filming the activities of humans and animals, or digital camera, with the development of electronic technology, heat
Pyroelectric infrared sensors will be more widely used in the field of automatic control.