Download mobile phone detector

MOBILE PHONE DETECTOR
PROJECT GUIDE
Mr.M.Manikandan
Asst Professor(ECE)
PRESENTED BY
P.Salini Sebasty
G.Sangeetha
K.Sherine Weeber
CONTENTS
 Objective
 Introduction
 Basic Principle
 Circuit diagram.
 Components.
 Circuit design.
 Mobile phone tracking operation.
 Applications.
 Limitations of mobile phone detector circuit.
OBJECTIVE
 To detect the presence of an activated mobile phone.
 For detecting the use of mobile phone for spying and
unauthorized video transmission.
INTRODUCTION
 With advancement in communication technology, the
requirement of cell phones has increased manifold.
 This project is used to develop a mobile detector that can
sense the presence of an activated mobile phone.
 The moment the circuit detects RF transmission signal
from an activated mobile phone the LED blinks.
 The LED continues to blink until the signal transmission
ceases.
BASIC PRINCIPLE
 The basic principle behind the circuit is the idea of using
a schottky diode to detect the cell phone signal.
 Schottky diodes rectifies low frequency signals with low
noise rate.
 The low power signal can be amplified and used to
power any indicator like an LED in this case.
CIRCUIT DIAGRAM
Mobile Phone Detector Circuit
CIRCUIT
COMPONENTS
 V1 = 12V
 L1 = 10uH
 R1 = 100Ohms
 C1 = 100nF
 R2 = 100K
 R3 = 3K
 Q1 = BC547
 R4 = 200 Ohms
 R5 = 100 Ohms
 IC1= LM339
 R6 = 10 Ohms
 LED = Blue LED
CIRCUIT DESIGN
 DETECTOR CIRCUIT:

The detector circuit consists of an inductor, diode, a
capacitor and a resistor.
 COMPARATOR CIRCUIT:

LM339 is used as a comparator . The reference
voltage is set at the inverting terminal using a potential
divider arrangement.
 AMPLIFIER CIRCUIT:
 A simple BJT BC547 is used in a common emitter mode.
 The battery voltage is 12V .the operating point collector emitter
voltage is 5V and collector current is 2mA.
LM339 PIN DIAGRAM
MOBILE PHONE TRACKING
OPERATION
 When a mobile phone is present near the signal, a
voltage is induced in the choke and the signal is
demodulated by the diode.
 This input voltage is amplified by the common emitter
transistor.
 The output voltage is more than the reference output
voltage producing a logic high signal and the LED starts
glowing, to indicate the presence of a mobile phone.
 The circuit has to be placed centimeters away from the
object to be detected.
APPLICATIONS
 Petrol pumps
 Gas station
 Historical places
 Religious places
 Court of laws
 Examination halls
 Spying and unauthorized video transmission
 Military bases
 Hospitals
 Theatres
 Conferences
 Embassies
LIMITATIONS OF MOBILE PHONE
DETECTOR
 It is a low range detector , of the order of centimeters.
 The schottky diode with higher barrier height is less
sensitive to small signals
FUTURE SCOPE:
 Trying to increase the detecting range of mobile from
centimeters to few meters.
 This can be achieved using either microcontroller or a 555
Timer.
Thank you