A
SEMINAR REPORT
ON
HIDDEN ACTIVE CELL PHONE DETECTOR
Submitted by
UVAIS AHMAD
ROLL NO. 14CH56
In partial fulfillment for the award of my degree of
BACHELOR OF TECHNOLOGY
IN
ELECTRICAL ENGINEERING
AT
DEPARTMENT OF ELECTRICAL ENGINEERING
MAHATMA JYOTIBA PHULE ROHILKHAND UNIVERSITY
BAREILLY-243006
CERTIFICATE
This is to certify that Uvais Ahmad (14CH56), have satisfactorily completed the seminar report
entitled HIDDEN ACTIVE CELL PHONE DETECTOR in his own work carried out in the
seventh semester by UVAIS AHMAD in partial fulfillment of the requirements for the award
of the degree of Bachelor of Technology from Institute of Engineering and Technology
Mahatma Jyotiba Phule Rohilkhand University,Bareilly , during academic year 2017-2018.
Ms. Jyoti Mr. Ashish Kumar Shankwar
Seminar Guide Seminar In-charge
ABSTRACT
Cell phones have brought the world closer. Communication has become a lot smoother with the
ease of using cell phone technology. It has made it possible for a person located in a remote
place to communicate with a person across the globe in a fraction of a second. However the
proliferate use of cell phones has somewhat made it obligatory for us to dig a way out to prevent
its usage in restricted or high security areas. This paper deals detection of GSM signals and
displaying it on a LCD screen with the help of a ATmega-8 microcontroller. This device will
ameliorate the attempt to maintain information security in restricted areas and prevent the breach
of potent data.
CONTENT
Name Page No.
ABSTRACT ...5
INTRODUCTION ..............6
USE OF CELL PHONE DETECTOR ...7
FREQUENCY RANGE OF DETECTOR .8
COMPONENTS ....9
DESIGNOBJECTIVES ....10
DESIGN SPECIFICATIONS .....10
KEYWORDS ..10
BASIC BLOCK DIAGRAM .......10
OPERATIONAL AMPLIFIER ...11
MONOSTABLE MULTIVIBRATOR ...12
PIEZO SENSOR ..13
MOBILE DETECTOR WORKING ....14
INTERFACING SECTION .....15
DESIGN SPECIFICATION ...15
APPLICATIONS OF CELL PHONE DETECTOR .....16
ADVANTAGES OF CELL PHONE DETECTOR ..16
FUTURE SCOPE .16
CONCLUSIONS ..17
REFERENCES ....18
INTRODUCTION
Cell phone technology is one that is ubiquitous and is progressing by every passing day. The
rapid proliferation of cell phones at the beginning of the 21st century eventually raised problems
such as their potential use to invade privacy or contribute to rampant and egregious academic
cheating. In addition public backlash was growing against the intrusive disruption cell phones
introduced in daily life.
A very common scenario is one of students operating cell phones in examination halls where its
use is obviously restricted. The examiners have to personally go the student and check his
pockets or desks for any cell phone. With the help of a cell phone detector the examiner will
know if a cell phone is active and can take action immediately.
The Intelligent Mobile phone detection project is an advanced device which finds various
applications in the modern fields of communication and surveillances. This work is very useful
for the private meetings, examination hall, defense establishments, military camp, Hospitals;
Petrol pumps etc., where the uses of an active Mobile Communication (GSM) device are
prohibited.
USE OF CELL PHONE DETECTOR
It is also useful for detecting the use of mobile phone for spying and un-authorized video
transmission.
Certain where use of mobile phones are not allowed like exam hall, temple, offices and theaters,
in those places to restrict the use of mobile phones this proposed system is very helpful.
This must detect the incoming and calls, SMS and video transmission even if the mobile phone is
kept in the silent mode. The illegal use of cell growing and dangerous problem in correctional
institutions worldwide.
These devices are a significant threat security and circumvent the monitoring processes in
prisons, while helping inmates commit new crimes both outside the facility.
FREQUENCY RANGE OF DETECTOR
The transmission frequency of mobile phones ranges from 0.9 to 3 GHz with a wavelength of 3.3
to 10 cm. detecting gigahertz signals is required for a mobile bug. The lead length of the
capacitor is fixed as 18 spacing of 8 mm between the leads to get the desired frequency. The disk
capacitor along with the leads acts gigahertz loop antenna to collect the RF signals from the
mobile phone.
When mobile phone is active, it transmits the signal in the form of sine wave which passes
through the encoded audio/video signal contains electromagnetic radiation which is picked up by
the receiver in the base The transmitter power of the modern 2G antenna in the base station is 20-
100 watts. The mobile phone transmits signals at regular intervals to register its availability to
the nearest base station. Distance to cellular base station most important environmental factor.
Generally, the nearer a cellular phone is to a base station or transmitting weaker will be the
signal that needs to come from the phone. Range of frequencies of different categories are,
frequencies between 180 kHz and 1.6MHz,FM radio uses 88 to 180 MHz, TV uses 470 to
854MHz.waves frequencies but within the RF region is called Micro waves. Mobile phone uses
high frequency RF wave region carrying huge amount of electromagnetic energy.
COMPONENTS
CA3130 - op-amp
PCB
Resistors all 1/4W
1.2M Ohm - 1
2.2M Ohm -1
1K Ohm -1
100K Ohm 1
Capacitors
22 pf ceramic -3
0.22uf ceramic -1
pf polyester/ceramic -1
100uF/25V Electrolytic -1
Red LED -1
BC548 -1
5Cm copper wire -1
DESIGN OBJECTIVES
The objective includes building a mobile detector to locate a phone within a range of 4-5meters
and display on a LCD screen on detection.
DESIGN SPECIFICATIONS
The frequency range up to which the detector is able to detect signals is about 0.9-3 GHz.
KEYWORDS
Cell Phone Detector, GSM Signal, Atmega-8, Communication, Restricted Areas
BASIC BLOCK DIAGRAM
Figure: Block Diagram of Cell Phone Detector
OPERATIONAL AMPLIFIER
The input of the operational amplifier is antenna signal and the op-amp consists of 8-pins. Op-
amp is an integrated circuit and it consists of two inputs with opposite polarities.
The o/p signal of the operational amplifier is very high when compared to the input signal and
the main the op-amp is to perform arithmetic operations on an analog circuit.
Figure: Operational Amplifier
MONOSTABLE MULTIVIBRATOR
The output signal of the operational amplifier is fed to a monostable multivibrator. The main
unction vibrator is to generate a single pulse.
In this mode of operation, one state of the o/p is balanced and another state of o/p is in
unbalanced mode.
This multi vibrator is activated when a logic low signal is given to the i/p and a high logic signal
appears at When it is not activated, the o/p of the multi vibrator is normally low. And when it is
activated it will go short length of time based on the values of the resistor and capacitor.
Figure: Monostable Multivibrator using 555 timer
PIEZO SENSOR
When the o/p of the multi vibrator touches the buzzer, then it generates the sound to specify the
active action cell phone.
The element of the piezoelectric may be driven by an oscillating electronic circuit and sounds are
commonly denote that a button has been pushed are a ring, a click or a beep.
The circuit in the above can be used to detect both the incoming & outgoing calls, video
transmission and the cell phone is kept in the mode of silent. The moment the bug notices Radio
Freuency transmission signal triggered mobile phone, it starts generating a beep alarm and also
the LED glows. The beep sound remains signal transmission ends.
Figure: Piezo Buzzer
MOBILE DETECTOR WORKING
Capacitor C3 in conjunction with the lead inductance acts as a transmission line that
intercepts the signals from the mobile phone.
This capacitor creates a field, stores energy and transfers the stored energy in the form of
current to the inputs of IC1. This will upset the balanced input of IC1 and convert the
current into the corresponding output voltage.
Op-amp IC CA3130 (IC1) is used in the circuit as a current-to-voltage converter with
capacitor C3 connected between its inverting and non-inverting inputs.
It is a CMOS version using gate-protected p-channel MOSFET transistors in the input to
provide very high input impedance, very low input current and very high speed of
performance.
Capacitor C4 along with high-value resistor R1 keeps the non-inverting input stable for
easy swing of the output to high state. Resistor R2 provides the discharge path for
capacitor C4.
Feedback resistor R3 makes the inverting input high when the output becomes high.
Capacitor C5 (47pF) is connected across strobe (pin 0 and null inputs (pin 1) of IC1
for phase compensation and gain control to optimize the frequency response.
When the mobile phone signal is detected by C3, the output of IC1 becomes high and low
alternately according to the frequency of the signal as indicated by LED1. This triggers
Monostable timer IC2 through capacitor C7.
Capacitor C6 maintains the base bias of transistor T1 or fast switching action. The low-
value timing components R6 and C9 produce very short time delay to avoid audio
nuisance.
CIRCUIT DIAGRAM
INTERFACING SECTION
An input from the mobile detector section is provided to the ATmega-8 microcontroller. On
detection a message saying MOBILE PHONE DETECTED is displayed on the LCD screen.
DESIGN SPECIFICATIONS
Interfacing is done via AVR using ATmega8 microcontroller. ATmega8 is 8-bitAtmel with
8KBytes In-System Programmable Flash. 32 8 General Purpose Working Registers. Up to
16MIPS Throughput at 16MHz.
APPLICATIONS OF CELL PHONE DETECTOR
It is useful where the use of mobile phone is prohibited like:-
Petrol pumps
Gas station
Historical places
Religious places
Court of laws
Examination halls
Spying and unauthorized video transmission
Military bases
Hospitals
Theatres
Conferences
Embassies
ADVANTAGES OF CELL PHONE DETECTOR
Smaller in size
Detection of hidden cell phones
FUTURE SCOPE
Improving the range: - If a preamplifier stage using JFET or MOSFET transistor is used as an
interface between the capacitor and IC, range can be increased.
Being able to detect Bluetooth transfers.
Current system is designed only for 2G/3G systems. A 4G complaisant system is to be
developed.
CONCLUSIONS
During tests and exams the use of mobile phones is prohibited, for the students could use it to
send answers to each other. By using a Cell phone-detector this kind of malpractice can be
avoided. The presence of a Cell phone-detector can work in a preventing way, because when a
Cell phone-detector is present, the use of mobile phones does not stay unnoticed. Just like within
theatres the use of mobile phones is not allowed. The Cell Phone Detector can be used to prevent
use. While refueling at a petrol station, the use of mobile phones is prohibited, because the
mobile signals can interfere with the refueling equipment and because a small spark within the
mobile phone could set fire to possible gasoline vapor. With the cell phone-detector this risk is
pointed out to the offending customer.
It is often distracting to be called during a meeting. Also, confidential
conversation can be overheard by using cell phones, especially by those with a spy function
(when someone calls that phone it automatically is picked up without ringing, so that the person
on the other end of the line can hear conversations in the room where the spy phone is
placed).By using a cell phone-detector you can be assured that this is not the case.
REFERENCES
Nicholas Scott-Study of cell phone detection techniques.
http://digitalcommons.unl.edu
http://gsmdetector.com/eng/apps.html
GSM techniques/control techniques-www.wikipedia.com
AVR interface and control-www.wikipedia.com
