This chip takes the output of the sensor and does some minor processing on it to emit a . Most of the real magic happens with the optics. This automatic staircase light circuit switch on the staircase lights automatically when someone enters on the stairs and gets off after some time. There are two important components in this circuit , first is PIR Sensor (Passive Infrared Sensor ) and second is Relay. It turns out that most of the cheap PIR modules sold for use with Arduinos have the facility to add an LDR (Light Dependent Resistor) so they only activate a.

If you do not add the LDR to the empty area of the .

Our bodies generate infrared heat .
PIR stands for Passive InfraRed. To detect movement or motion of person the simple PIR (Passive InfraRed) circuit can be use it gives reliable output than simple photocell or photo diode circuits. Check out the updated version of this circuit. The sensor can also pick up the movement of inanimate objects as well, such a . In our article titled PIR Sensors we introduced passive infrared ( PIR ) sensors and summarised their uses.






