<ul><li>Owing to the increase in the mechanical life we couldn’t pay a rapt attention towards the security related problems. In this era people used Hi-tech methods to steal others property.
Here a sensing circuit installed is the monostable mode of IC555 which is available in the market at ease. Here the circuit provides an input to the microcontroller, which is PIC16F877p.
The reference condition is continually compared with the present situation at any instant and the error is calculated then necessary decision will be taken by the controller which is already given as a condition to the controller.
This security system safeguards a certain area.
This is simple and provides higher performance.</li></li></ul><li>CIRCUIT DIAGRAM<br />
BLOCK-1 MONOSTABLE MULTIVIBRATOR SECTION <br />Most darkness activated alarms employ op-amps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this time in monostable multivibrator mode.<br />
BLOCK-1 OPERATION<br /><ul><li>Here, a less expensive approach is shown based on the eternal 555, </li></ul>this time in monostable mode.<br /><ul><li>When the LDR (light dependent resistor) is in the dark, its resistance is high, pulling pin 2 of the 555 to ground. This triggers the monostable and the (active!) 6-volt piezo buzzer will sound. Preset P1 is adjusted depending on ambient light levels.
The circuit may be fitted on a wall in your home. Assuming P1 has been set for the existing ambient light level, the shadow cast by anybody entering the room or hallway will trigger the alarm.</li></li></ul><li>BLOCK-2 MICROCONTROLLER SECTION. <br />This is the schematic pin configuration of the PIC 16F877A.<br />
DC REGULATOR <br />SECTION<br />Ic 7805, which is the voltage regulator used here to feed the input pin of the controller with 5V.<br />2) Here the port A is used as an input so there should be a 10K resistor due to open drain characteristics of the MOS technology.<br />3) Similarly for the VSS and VDD pins a 7805 regulator is placed to regulate the unregulated DC supply into a regulated one.<br />
SOFTWARE USED<br />Software<br />Purpose<br />Mplab TOOLS V5.80 VERSION <br />Ic prog<br />For simulating the program and to create the HEX file.<br />To burn the software to PIC controller.<br />
Here the output is given to 7 segment display.<br />Alphabetic values pictures the present condition at any instant.<br />Under normal operation:<br /> “C” - will be displayed which is CLEAR and no problem.<br />Under faulty mode:<br /> “P” -will be displayed which means problem.<br />OUTPUT<br />
SYSTEM OPERATION UNDER NORMAL MODE<br /><ul><li>In normal operation the laser will be emitting the laser beam from transmitter and it travels in the straight line without showing any visual appearance to us.
Meanwhile, the reflecting glasses will be placed in every corners such that the beam will be directed exactly to the next mirror with a change in direction. When the LDR (light dependent resistor) is in the dark, its resistance is high, pulling pin 2 of the 555 to ground. This triggers the monostable and the (active!) 6-volt piezo buzzer will sound. Preset P1 is adjusted depending on ambient light levels.
The glasses are reflective which won't allow the beam to pass through it.</li></ul>when the beam reaches the LDR which is covered from the external light absorb the beam alone and become good conductor. This condition ensures that there is no interruption and no one is crossing the boundary so the items inside the boundary is safe enough. <br />
UNDER FAULTY CONDITION<br /><ul><li> In case of any interrupt occurs in any where the beam interruption will takes place.
When the beam not link the LDR the monostable circuit will be triggered and output will be available at pin3 in first block and passed to controller through various sections.
In case of any thief crosses the boundary the beam interruption will be made and the buzzer start BUZZ sound which will alert the watchman...</li></li></ul><li>FUTURE WORK<br /> <br /><ul><li>In future many small circuits can be integrated with the PIC controller which will serve much the human comfort and it will be a good servant.</li></ul> <br /><ul><li>Some functions that can be integrated are watch dog for your home, gas leakage sensor, and power failure alarm, automatic turn on and OFF control of devises.</li></ul> <br /><ul><li>In future the thing that can be used is if any fault occurs the automated system will immediately call the emergency numbers 112, 911 automatically and play the recorded voice regarding the type of fault and the degree of fault.</li></li></ul><li>REFERENCE<br /><ul><li>http://www.eleccircuit.com/simple-darkness-activated-alarm-by-ic-ic555