If you want to do a quick test before going ahead with this tutorial please follow the steps below.Ī testing is also a good idea to test the range and duration of sensing.An IR sensor is a device that measures the Infrared radiation in its surroundings and gives an electric signal as an output. I will be using this mode for this project.

> 2nd one is called 'repeatable trigger' - it stays high as long as the object is in the proximity and will turn off once the object is gone and the delay is over. > 1st one is called 'non-repeatable trigger' - this one goes low as soon as the delay time is over. There are 3 more pins on this module with a jumper between them to select the trigger modes. The module has two potentiometers one to adjust the sensitivity (which is up to 7m) and the other to adjust the time for which the output signal should stay high when an object is detected (it ranges from 0.3s to 5 mins). The BISS0001 or the 'Micro Power PIR Motion Detector IC' gets the output from the sensor and after doing some minor processing it produces the digital output. The pin-outs may vary between modules so always triple-check the pin-outs. The OUTPUT pin is the one which communicates with the micro-controller by sending digital pulse high (3.3v) when a motion is detected and digital low (0v) when no motion is detected.

VCC and GND are to power the module (Operating voltage: DC 5V to 20V). Most PIR sensors have 3-pins VCC, GND and OUT. The bottom bit consists of a bunch of circuitry. When the pulse changes or in other words the PIR sensor detects motion, the output pin changes to 'digital high' or 3.3V. And then, when it leaves the sensing area, the reverse happens, and the sensor generates a negative differential change. When a warm body passes by, it first intercepts one of the two sensors, causing a positive differential change between the two halves. In idle state, both sensors detect the same amount of IR radiation. Behind this window are 'two' balanced PIR sensors. There is a tiny window made of IR-transmissive material to allow the IR signals to reach the sensor. The can basically protects the sensor from noise, temperature and humidity.

The actual sensor is inside a sealed metal can. The sensors sensitivity range between 6 to 7 meters (20 feet) and the detection angle is 110 degrees x 70 degrees. 9.4 µMeter infrared rays can easily pass through the polyethylene cover. This lens focuses the infrared rays to the underlying 'Pyroelectric Sensor'. The Top consist of a specially designed 'High-Density Polythene' cover called 'Fresnel Lens'.

Proteus infrared sensor