08-08-2012, 10:59 AM
MOBILE DETECTION IN EXAM HAL
MOBILE DETECTION IN EXAM HALL.pptx (Size: 1.02 MB / Downloads: 66)
Purpose of the project
It some times is not possible to detect mobile phones with students in exam halls.To resolve this problem this projects gives a solution.
The project helps in detecting the mobile phone and gives a buzzer sound as an indication.
Existing model
We in general try to detect the mobile phones with students my manual checking.
But the students now a days are very talented, of course in every aspect.
This device helps in trapping the such clever students also.
IMPLEMENTATION
This project uses
Micro controller
Power supply ckt
LCD
Operational amplifier
555 Timer
Buzzer and a
Sensing coil
for the detection
The mobile when in usage is detected by using a mobile detector circuit. This circuit uses op-amp and the timer.
The mobile when not in usage is detected using a metal detector circuit. This circuit uses the sensing coil.
POWER SUPPLY CKT
We in general receive 230 v of power supply from the mains.
But a micro controller can’t work with this voltage. So we employ a transformer.
Micro controller(AT89S52)
Every component
in the trainer is
interfaced with the
micro controller to
make the result
appear through the
respective output
Features of AT89S52
Compatible with MCS®-51 Products
8K Bytes of In-System Programmable (ISP) Flash Memory
Endurance: 10,000 Write/Erase Cycles
4.0V to 5.5V Operating Range
Fully Static Operation: 0 Hz to 33 MHz
Three-level Program Memory Lock
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Full Duplex UART Serial Channel
Low-power Idle and Power-down Modes
Interrupt Recovery from Power-down Mode
Watchdog Timer • Dual Data Pointer
Power-off Flag • Fast Programming Time
Flexible ISP Programming (Byte and Page Mode)
Green (Pb/Halide-free) Packaging Option
Operational amplifier
V+ -Non inverting i/p
V- -Inverting i/p
Vout- o/p
Vs+ -positive power supply
Vs- -negative power supply
555 TIMER
GND : Ground, low level
(0 V)
TRIG : OUT rises, and interval starts, when this input falls below 1/3 VCC.
OUT : This output is driven to +VCC or GND.
RESET : A timing interval may be interrupted by driving this input to GND.
CTRL : "Control" access to the internal voltage divider (by default, 2/3 VCC).
THR : The interval ends when the voltage at THR is greater than at CTRL.
DIS : Open collector output; may discharge a capacitor between intervals.
V+, VCC : Positive supply voltage is usually between 3 and 15 V.
Modes of 555 Timer operation
It operates in three modes
1.Monostable mode
2.Astable mode
3.Bistable mode
Monostable mode
Bistable mode
Astable mode
BUZZER
A buzzer is an audio
signaling device used to
give a confirmation sound.
In general they are of three types :
Mechanical
Electro mechanical and
Electronic buzzers
Sensing coil
A sensing coil is nothing but a copper coil with too many windings with a diameter.
Applications
This circuit can be applied for class rooms and exam halls
These can also be used in conference halls and offices where mobiles are not allowed.