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DIGITAL SECURITY SYSTEM. By R.Sree Harsha M.Sai Sudeep Reddy. What is Digital Security?. It is a type of security which can be used to prevent intruders from entering our home. The security system will sound an alert if there an attempt of break-in.
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DIGITAL SECURITY SYSTEM By R.SreeHarsha M.SaiSudeep Reddy
What is Digital Security? • It is a type of security which can be used to prevent intruders from entering our home. • The security system will sound an alert if there an attempt of break-in. • This is mainly used to minimize chances of losing possessions which can be traumatic and expensive. • When the intruder breaks in, the alarm will sound and most times will scare them off. • Limitations : The alarm will sound even if the user or his friends enter his home, providing an inconvenience to the user.
Electronic Components • 5 Resistors: One 470 ῼ One 1K ῼ Three 47K ῼ resistors • Semi-Conductors: IC 1 – CD4511 IC 2 – CD4000 Q1 – BC 548 Display – LTS 543 • Miscellaneous: Two one way switches BZ – Buzzer IC Socket – 16 PIN-1 , 14 PIN-1 PCB
Circuit Construction • Wire loops 1,2 and 4 are connected to A,B and C inputs of the 7-segment decoder (IC 4511) while the D input of IC1 is grounded permanently. • The loops are also connected to a dual 3-input NOR gate which is then connected to a NOT gate to activate the alarm. • The 7-segment decoder is connected to a common cathode 7-segment display(LTS 543).
Brief Mechanism of Circuit • LTS 543 displays whether the loops are intact or not. • When the loops are intact, all the three inputs of the gate N1 remain low to give a high output. • This high output is further given to the NOT gate and as a result the final output remains low. This keeps the transistor in cut-off position and hence the buzzer does not sound. • When any loop is broken, the output of the N1 gate goes low. • As the input of the NOT gate is low, the final output will be high. • As the final output is high, the transistor conducts and the buzzer sounds to alarm the owner.
If the loop 1 is broken, the 7-segment display will show ‘1’. • Similarly if the loop 4 is broken, it shows ‘4’. • If both the loops 1 and 4 are broken, then it shows ‘5’ (1+4).