Passive Infrared Sensor which uses the IR to detect the motion.
- PIR are basically made of a pyroelectric sensor.
- It detects an object has moved in or out of the sensor range.
- The round metal with a rectangular crystal in the centre , which can detect level of infrared radiation.
- The sensor in a motion detector is actually split in two halves.
- When sensor is idle, both slots detect the same amount of IR.
- When motion detected it first intercepts one half of the PIR sensor.
- When the warm body leaves the sensing area, the reverse happens, whereby the sensor generates a negative differential change.
- The PIR detects motion, the output pin will go “high” to 3.3V.
- Motion Detection System.
- Pir Sensor.
- 8051 MicroController.
- Vcc: +5v.
- OutPut:Digital Pulse.
- Gnd: Gnd.