28-12-2012, 12:53 PM
PROJECT REPORT ON WATCHMAN WATCHER
[attachment=45544]
Introduction
Here is a circuit that can be used in offices, stores, warehouses, etc during night to check whether the watchman of your establishment is on duty. For operation, it uses an existing telephone .The watchman is given an audio alert signal by just ringing the office/store telephone once (minimum) from your residence or any other place, preferably using your mobile phone. The ring is detected by the given circuit and the watchman is also given a visual alert signal by a glowing lamp. The lamp remains ‘on’ for a duration of nearly 60 seconds soon after the ring tone. The watchman is given an instruction to register his presence by simply pointing his torch-light beam towards a wall-mounted LDR sensor unit . If he fails to do it within the permissible time, the circuit registers his absence by incrementing a count. If he does, the count remains unaltered.
DESCRIPTION OF COMPONENETS
1)TRANSISTOR
A transistor is a semiconductor device used to amplify and switch electonics signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit.
A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal. Today, some transistors are packaged individually, but many more are found embedded in integrating circuits.
2)RESISTOR
A resistor is a two- terminal passive electronic component which implements electrical resistance as a circuit element. When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage. This constant of proportionality is called conductance, G. The reciprocal of the conductance is known as the resistance R, since, with a given voltage V, a larger value of R further "resists" the flow of current I as given by ohms law:
I=V/R
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in most electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire(wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits particularly analog devices, and can also be integrated into hybrid and printed circuits.
3)INTEGRATED CIRCUIT
An integrated circuit or monolithic integrated circuit (also referred to as IC, chip, and microchip) is an electronic circuit manufactured by diffusion of trace elements into the surface of a thin substrate of semiconductor material.
4)CAPACITOR
A capacitor is an electrical device that can store energy in the electric field between a pair of closely-spaced conductors (called 'plates'). When voltage is applied to the capacitor, electric charges of equal magnitude, but opposite polarity, build up on each plate. Capacitors are used in electrical circuits as energy-storage devices.
5)REALY
The relay is a well known and widely used component Applications range from classic panel built control systems to modem interfaces between control microprocessors and their power circuits or any application where reliable galvanic separation is recpied between different circuits.
WORKING OF PROJECT
The telephone lines (TIP and RING) Counter 74LS192 (IC7) is reset to zero state by making its reset pin 14 high through reset switch S1. The 7-segment, common-anode display DIS1 is driven through IC 74LS47 (IC8). When the phone rings, count ‘1’ is displayed after nearly one minute. This happens if the watchman fails to focus the torchlight beam on LDR1.
If LDR1 receives light from the torch of the watchman within the allowed time period, the down clock remains high until the up clock is high. The counter counts up and then down, so, in effect, the count remains unchanged.
All components, except LDR1, are kept in a sealed cabinet with locking arrangement. Only LDR1 is wall-mounted and visible outside. This is done to avoid manual resetting of the counter. The circuit is to be powered by a battery to avoid resetting of the count during power failure.
The working procedure can be summarised as follows:
1. Initially, when the power supply is switched on, power-on-reset components C8 and R13 reset counter IC7 and the display shows ‘0.’
2. Now dial the telephone number (where parallel system is installed) from outside or from your mobile. For the first ring, relay RL1 energises and alert lamp L1 glows.
3.When alert lamp L1 is off, the counter is incremented by ‘1.’
4. If the watchman focuses the torch-light beam on LDR1 within the glowing time of alert lamp L1, the counter first counts up and then counts down and finally the display shows 0. This indicates that the watchman is present.
5. If the watchman focuses the torch-light beam on LDR1 after alert lamp L1 goes off, up-counting takes place and the display shows ‘1.’ This indicates that the watchman is absent.
[attachment=45544]
Introduction
Here is a circuit that can be used in offices, stores, warehouses, etc during night to check whether the watchman of your establishment is on duty. For operation, it uses an existing telephone .The watchman is given an audio alert signal by just ringing the office/store telephone once (minimum) from your residence or any other place, preferably using your mobile phone. The ring is detected by the given circuit and the watchman is also given a visual alert signal by a glowing lamp. The lamp remains ‘on’ for a duration of nearly 60 seconds soon after the ring tone. The watchman is given an instruction to register his presence by simply pointing his torch-light beam towards a wall-mounted LDR sensor unit . If he fails to do it within the permissible time, the circuit registers his absence by incrementing a count. If he does, the count remains unaltered.
DESCRIPTION OF COMPONENETS
1)TRANSISTOR
A transistor is a semiconductor device used to amplify and switch electonics signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit.
A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal. Today, some transistors are packaged individually, but many more are found embedded in integrating circuits.
2)RESISTOR
A resistor is a two- terminal passive electronic component which implements electrical resistance as a circuit element. When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage. This constant of proportionality is called conductance, G. The reciprocal of the conductance is known as the resistance R, since, with a given voltage V, a larger value of R further "resists" the flow of current I as given by ohms law:
I=V/R
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in most electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire(wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits particularly analog devices, and can also be integrated into hybrid and printed circuits.
3)INTEGRATED CIRCUIT
An integrated circuit or monolithic integrated circuit (also referred to as IC, chip, and microchip) is an electronic circuit manufactured by diffusion of trace elements into the surface of a thin substrate of semiconductor material.
4)CAPACITOR
A capacitor is an electrical device that can store energy in the electric field between a pair of closely-spaced conductors (called 'plates'). When voltage is applied to the capacitor, electric charges of equal magnitude, but opposite polarity, build up on each plate. Capacitors are used in electrical circuits as energy-storage devices.
5)REALY
The relay is a well known and widely used component Applications range from classic panel built control systems to modem interfaces between control microprocessors and their power circuits or any application where reliable galvanic separation is recpied between different circuits.
WORKING OF PROJECT
The telephone lines (TIP and RING) Counter 74LS192 (IC7) is reset to zero state by making its reset pin 14 high through reset switch S1. The 7-segment, common-anode display DIS1 is driven through IC 74LS47 (IC8). When the phone rings, count ‘1’ is displayed after nearly one minute. This happens if the watchman fails to focus the torchlight beam on LDR1.
If LDR1 receives light from the torch of the watchman within the allowed time period, the down clock remains high until the up clock is high. The counter counts up and then down, so, in effect, the count remains unchanged.
All components, except LDR1, are kept in a sealed cabinet with locking arrangement. Only LDR1 is wall-mounted and visible outside. This is done to avoid manual resetting of the counter. The circuit is to be powered by a battery to avoid resetting of the count during power failure.
The working procedure can be summarised as follows:
1. Initially, when the power supply is switched on, power-on-reset components C8 and R13 reset counter IC7 and the display shows ‘0.’
2. Now dial the telephone number (where parallel system is installed) from outside or from your mobile. For the first ring, relay RL1 energises and alert lamp L1 glows.
3.When alert lamp L1 is off, the counter is incremented by ‘1.’
4. If the watchman focuses the torch-light beam on LDR1 within the glowing time of alert lamp L1, the counter first counts up and then counts down and finally the display shows 0. This indicates that the watchman is present.
5. If the watchman focuses the torch-light beam on LDR1 after alert lamp L1 goes off, up-counting takes place and the display shows ‘1.’ This indicates that the watchman is absent.