16-08-2012, 12:12 PM
Project on Four way Security System
4 way security system.doc (Size: 2.09 MB / Downloads: 50)
Description:-
Four way security system project consist of three basic modules. First is IR transmitter and receiver module which works for the safety of doors at night or in case we are out of home. When the IR sensors are interrupted, a buzzer if turned on indicating someone is entered into house. By the help of this project we can secure office ,industries ,Bank and Home easily through electronics security system.
CIRCUIT DESCRIPTION
POWER SUPPLY(+ive)
Circuit connection: - In this we are using Transformer (0-12) v, 1Amp,LED & resistors. Here 230V, 50 Hz ac signal is given as input to the primary of the transformer and the secondary of the transformer is given to the bridge rectification diode.
Circuit Explanations: -
When ac signal is given to the primary of the transformer, due to the magnetic effect of the coil magnetic flux is induced in the coil(primary) and transfer to the secondary coil of the transformer due to the transformer action.” Transformer is an electromechanical static device which transformer electrical energy from one coil to another without changing its frequency”. Here the diodes are connected in a bridge fashion. The secondary coil of the transformer is given to the bridge circuit for rectification purposes. During the +ve cycle of the ac signal the diodes D2 & D4 conduct due to the forward bias of the diodes and diodes D1 & D3 does not conduct due to the reversed bias of the diodes. Similarly during the –ve cycle of the ac signal the diodes D1 & D3 conduct due to the forward bias of the diodes and the diodes D2 & D4 does not conduct due to reversed bias of the diodes. The output of the bridge rectifier is not a power dc along with rippled ac is also present. To overcome this effect, a capacitor is connected to the o/p of the diodes (D2 & D3). Which removes the unwanted ac signal and thus a pure dc obtained. Here we need a fixed voltage, that’s for we are using IC regulators. The o/p of the bridge rectifier is given as input to the IC regulator through capacitor with respect to GND and thus a fixed o/p is obtained. The o/p of the IC regulator (7805 & 7812) is given to the LED for indication purpose through resistor. Due to the forward bias of the LED, the LED glows ON state, and the o/p are obtained .
LED INDICATOR
The indicator section consists of a light emitting diode and its driver circuit is designed on the basis of current required to glow the light emitting diode. Here the driver circuit is required for the following functionality. The Microcontroller cannot provide adequate current for glowing the LED. The LEDs requires a current between 10mA to 20mA of current to glow. The driver circuit provides current to the load from a separate source, so the load current used not pass through the Microcontroller.
IR TRANSMITTER (transmitter zone)
The IR LED is also light emitting diode but the junction is made out of such material that the transition of electron between the bands emits quanta of energy( E=h) having a particular frequency which is having a particular characteristic. When a diode emits a particular characteristic signal having frequency in the range of infrared then, that diode is called a infrared emitting diode. The IR data transmitter is a high intensity IR signal transmitter. There are two diodes connected in parallel to increase the intensity to avoid data corruption receiver end. In this section our aim is to protect the zone/door/almira etc. from the unauthorized entry or interruption, for that we need some element that should not be visible to the unauthorized person. For that we have taken elements as IR LED as a source and photo diode as a destination. Generally, we have taken IR because IR is invisible to the eye, where as in case of LASER, which is easily visible to the human eye by which will, alert the unauthorized person. That is why we have taken IR as a transmitter which will transmit a continuously IR signal. At the receiver end the photodiode will receive the IR signal. if somebody tries to interrupt the IR signal at the transmitter end, the receiver will decide the absence of the IR signal at the receiver end.