The cheapest way to remote control a device within a visible range is via Infra-Red light. Almost all audio and video equipment can be controlled in this way now a days. Due to this wide spread use the required components are quite cheap, thus making it ideal for us to use IR control for our own projects. Infra-Red actually is normal light with a particular color. We humans can't see this color because its wave length of 950nm is below the visible spectrum. That's one of the reasons why IR is chosen for remote control purposes, we want to use it but we're not interested in seeing it. Another reason is because IR LED’s are quite easy to make, and therefore can be very cheap.
Present project is designed using 89S52 microcontroller to OPEN/CLOSE any kind of entry or exit doors, if implemented in spirit. This project utilizes two powerful IR transmitters and two receivers; one pair of transmitter and receiver is fixed at entry side (from where the customer comes) for a human being in exact alignment and similarly the other pair is fixed at exit side of the door. Sensor activation time is so adjusted by calculating the time taken by a personal to cross the signal from the transmitter and receiver. Sensors are fixed at 1meter on both sides of the door. When foreside receiver gets activated by recognizing any one entering, the gate motor is turned on in one direction and the gate is opened and stays opened until the person crosses the door and reaches the other side. When the exit side receiver gets activated motor turns in opposite direction and gate opens and motor stops. In this way the OPEN/CLOSE function of the ENTRY/EXIT door can be controlled.
    • Shopping malls
    • Movie theatres
    • Offices and Industries.
    • This can also be implemented to control the Railway gates.


Block diagram:...