Energy saving system using a PIR sensor for classroom monitoring

The work gives a report about the design of an energy saving system using a Passive Infrared Radio sensor to switch `off' fan and light circuits in the classroom in the absence of students. When a student enters the classroom, the Infrared energy emitted from the living body is focused by the Fresnel lens segment and the PIR sensors activate and give to the microcontroller which acts as power saving device according to the relay. When motion is detected the relays trigger and switch the fan and light `on' and after ten minutes to switch `off' the fan and light when motion has not been detected. The fan only switches `on' when the room attains a temperature of 25°C-30°C.