25-08-2017, 09:32 PM
A PROJECT REPORT ON MICROCONTROLLER BASED HOME SECURITY SYSTEM
1MICROCONTROLLER BASED HOME SECURITY.docx (Size: 380.24 KB / Downloads: 30)
ABSTRACT
Engineering is not only a theoretical study but it is a implementation of all we study for creating something new and making things more easy and useful through practical study. It is an art which can be gained with systematic study, observation and practice. In the college curriculum we usually get the theoretical knowledge of industries, and a little bit of implementation knowledge that how it is works? But how can we prove our practical knowledge to increase the productivity or efficiency of the industry?
Don’t take the chance of becoming victim of burglary, which is often accompanied by violence. Protect our family and valuables with this microcontroller based security system that will let us rest our head knowing that should anyone trying to break into our home, an alarm will go off and the police will be alerted immediately.
The transmitter section continuously transmits IR rays which are received by the receiver section. The received signal is further amplified and given to the PLL section, where its frequency is locked to the transmitted frequency.
When the IR signal is interrupted, the microcontroller starts working as per the program burnt into the EPROM and control the siren, telephone and cassette player via the respective relays.
Introduction:
Protect our family and valuables with this microcontroller based security system knowing that should anyone trying to break into our home, an alarm will go ON and the police will be alerted immediately.
The microcontroller based security system consists of transmitter, receiver, phase locked loop and processing section.
The transmitter section continuously transmits IR rays which are received by the receiver section. The received signal is further amplified and given to the PLL section, where its frequency is locked to the transmitted frequency. The transmitter and receiver are arranged such that the transmitted IR rays fall directly onto the phototransistor LI4GI of the receiver. The signal received by T2 is amplified by transistor T3 and operational amplifier µA741 (IC2). Series input resistor R8 and feedback resistor R9 determine the gain of op amplifier IC2. The amplified single so applied to pin 3 of PLLLM567 (IC3) through capacitor C4.
ICLM567 is highly stable PLL with synchronous AM lock detection and power output circuitry it is primarily used as frequency decoder which drives a load whenever a sustained frequency falling within its detection band is present in its self biased input. The centre frequency of the determined by external components.
In the absence of any input single, the center frequency of PLL’s eternal free running, current control oscillator is determined by resistor R12 abed capacitor C8.
Preset VR2 is used for tuning IC3 to the desired center frequency in the 6-10 kHz range,
Which should match the modulating frequency of the transmitter? Capacitor C6 and C7 are used as low pass filter. Ned out filter respectively when the received signal is locked to frequency of transmitter signal pin 8 of IC3 goes low and LED 1 glows. Since pin 8 is connected to the base of transistor T4 through R13 its collector voltage rises. As a result T5 is forward biased to energies the relay RL5 the pole and normally closed contact of really contact of RL5 are connected to +5v.
When the IR signal is interrupted, the microcontroller starts working as per the program burnt into the EPROM and control the siren, telephone and cassette player via the respective relays.
Receiver Section:
The transmitter and receiver are arranged such that the transmitted IR rays fall directly onto the phototransistor LI4GI of the receiver. The signal received by t2 is amplified by transistor t3 and operational amplifier µA741 (IC2). Series input resistor R8 and feedback resistor R9 determine the gain of op amplifier IC2. The amplified single so applied to pin 3 of PLLLM567 (IC3) through capacitor c4.
ICLM567 is highly stable PLL with synchronous AM lock detection and power output circuitry it is pre merely used as frequency decoder which drives a load whenever a sustained frequency falling within its detection band is present in its self biased input. The centre frequency of the determined by external components.
In the absence of any input single, the center frequency of PLL’s eternal free running, current control oscillator is determined by resistor R12 abed capacitor C8. Preset VR2 is used for tuning IC3 to the desired center frequency in the 6-10 kHz range, which should match the modulating frequency of the transmitter? Capacitor C6 and C7 are used as low pass filter. Ned out filter respectively when the received signal is locked to frequency of transmitter signal pin 8 of IC3 goes low and LED 1 glows. Since pin 8 is connected to the base of transistor T4 through R13 its collector
voltage rises. As a result T5 is forward biased to energies the relay RL5 the pole and normally closed contact of really contact of RL5 are connected to +5v.
The low order multiplex address and data lines AD0 though AD7 of IC4 are connected to the EPROM (IC5) through the latch(IC6), while its high order address line A8 through A10 are directly connected to the EPROM. Address lines A0 through A7. Are separated from data lines D0 through D7 by latch enable single.
Address latch – enable pin 30 of the microcontroller is connected to latch enable pin 11 Ic6. When ale high the latch us transparent. The output changes according the input data when ALE goes low, the low order address is latched at the input of IC6.
Data lines D0 throughD7 of microcontroller are connected to dated lines of IC5 and IC7 each. Chip sleets signal for IC5 is generated by RD and IO/M lines with the help of NAND gate. The inverted IO/M signal provides CS signal through IC7.
IC AT89C51 is general purpose programmable device compatible with most microcontrollers. It has three programmable ports, any of which can be ports and the remaining eight bits as port c.
The eight bits of ports c can be used as individual bits or grouped in two 4-bits ports namely, c (upper) and c (lower). Ports A and C are configured as input ports and port B is configured as output port A. is used for inter detection,portB for activating the siren, cassette player, telephone cradle switch and redial button and port C for polarity reversal detection.
Working of the Circuit:
The transmitting IR LED1 and phototransistor T2 of the receiver are fitted to the gate such the IR rays emitted by the LED directly fall on the phototransistor.
The IR LED transmits a train of IR pulses. These pulses are received by the receiver and amplified by IC2. Output pin 8 of the PLL (IC3) is low when the PLL network is locked to the transmitter frequency and relay RL5 energies to make PA line of IC7 low.
When someone walks through the gate to enter your home, the transmitted signal is interrupted. Output pin 8 of the PLL network goes high and relay RL5 de-energies to make PA0 line of IC7 high. Now the microprocessor starts working as per the program loaded in the EPROM.
Relay RL4 energies to activate the siren. At the same time, relay RL3 energizes to emulate lifting the telephone handset off the cradle to provide the dial tone. After a few seconds, relay RL2 energies to short the redial button contacts. After the loaded number is dialed, it switches off relay RL2. Then relay RL1 turns on the audio player.
Here we have provided the same polarity-reversal detection facility so that the audio player turns on only when polarity-reversal is detected.
The actual-size, double-size track lay-outs for solder and component sides of the PCB for the 8085 microprocessor-based home security system are shown in figs5 and figs6 , respectively, and their component layout in fig.7.
Description:
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4Kbytes of Flash programmable and erasable read only memory (PEROM). The devices manufactured using Atmel’shigh-density nonvolatile memory technology and incompatible with the industry standardMCS-51 instruction set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmen AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
3-TERMINAL 1A POSITIVE VOLTAGE REGULATORS
The LM78XX series of three-terminal positive regulators are available in the TO-220/D-PAK package and with several fixed output voltages, making them useful in a wide range of applications. Each type employs internal current limiting, thermal shut-down and safe area protection, making it essentially indestructible. If adequate heat sinking is provided, they can
Deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltages and currents.
Operation:
When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force that is half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing.
If the coil is energized with DC, a diode is frequently installed across the coil, to dissipate the energy from the collapsing magnetic field at deactivation, which would otherwise generate a spike of voltage and might cause damage to circuit components. If the coil is designed to be energized with AC, a small copper ring can be crimped to the end of the solenoid. This "shading ring" creates a small out-of-phase current, which increases the minimum pull on the armature during the AC cycle. [1]
Summary:
The microcontroller based security system consists of transmitter, receiver, phase locked loop and processing section.
The transmitter section continuously transmits IR rays which are received by the receiver section. The received signal is further amplified and given to t6he PLL section, where its frequency is locked to the transmitted frequency. The transmitter and receiver are arranged such that the transmitted IR rays fall directly onto the phototransistor LI4GI of the receiver. The signal received by t2 is amplified by transistor t3 and operational amplifier µA741 (IC2). Series input resistor R8 and feedback resistor R9 determine the gain of op amplifier IC2. The amplified single so applied to pin 3 of PLLLM567 (IC3) through capacitor c4.
ICLM567 is highly stable PLL with synchronous AM lock detection and power output circuitry it is pre merely used as frequency decoder which drives a load whenever a sustained frequency falling within its detection band is present in its self biased input. The centre frequency of the determined by external components.