HCSR501 PIR Motion Sensor (Passive Infrared Sensor)
The PIR Sensor module allows you to sense motion. It is almost always used to detect the motion of a human body within the sensor's range. It is often referred to used "PIR", "Pyroelectric", "Passive Infrared" and "IR Motion" sensor.
The module has an on-board pyroelectric sensor, conditioning circuitry and a dome shaped Fresnellens.
The PIR sensor module provides an output "HIGH" when a human body is detected within its range and an automatic Delay "LOW" when the body leaves its range. The delay time is adjustable using the potentiometer on-board. The minimum delay time that can be set is 5 seconds and maximum of 200 seconds.
Sensor module using a dual probe, the probe's window is rectangular, dual (A per B million) in the direction of the ends of long, when the body passed from left to right or right to left when the reach the dual IR time, distance difference, the greater the difference, more sensitive sensors, when the body from the front to the probe or from top to bottom or from bottom to top direction passing, dual IR not detected changes in the distance, no difference value, the sensor insensitive or does not work; so the sensors should be installed dual direction of the probe with human activities as much as possible parallel to the direction of maximum to ensure that the body has been passed by the dual sensor probe. To increase the sensing range of angles, the module using a circular lens, the probe also makes sense on all four sides, but still higher than the upper and lower left and right direction of sensing range, sensitivity and strong, still as far as possible by the above installation requirements.VCC, trig (control side), echo (receiving end), GND