This document provides information about a project to build an active cell phone detector circuit. It includes a circuit diagram and descriptions of the major components used, including the CA3130 and NE555 integrated circuits. The circuit works by using a capacitor to detect radio frequency signals from nearby cell phones, converting this to a voltage that triggers a monostable multivibrator to activate an alarm. The detector is able to identify incoming/outgoing calls and video transmission from phones within 1-1.5 meters.

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A Mini Project Report on
ACTIVE CELL PHONE DETECTOR USING CMOS & BIPOLAR
TRANSISTORS
Submitted to
T JOHN INSTITUTE OF TECHNOLOGY
Bangalore.
Bachelor of Engineering
In
Electronics and Communication Engineering
By
Shahrukh Javed BEE141570
Syed Moula BEE141528
Session: 2016-2017
Date of submission 13th
Oct 2016
UNDER THE ESTEEMED GUIDANCE OF
PROF. BASAVANAGOUDA
DEPARTMENT OF ECE.
Department of Electronics and Communication Engineering
T JOHN INSTITUTE OF TECHNOLOGY
(Visvesvaraya Technological University)
(Approved by AICTE, Affiliated to VTU & Accredited by NAAC)
86/3, Gottigere, Bannerghatta Road, Bangalore - 560083

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PREFACE
This project provides complete information on the topic “ACTIVE CELL
PHONE DETECTOR” and maximum efforts have been taken to make the
project more comprehensive and lucid to understand.
This project covers a variety of sub topics like basic information, its working,
day to day uses in life and different aspects of Mobile Detector System. One
may notice a perceptible change in written in an easy dialogue style engaging
the readers constantly and included with more informatics comments.
I assure you to go through this project thoroughly to know a bit more and facts
about Cell Phone Detector aka Mobile Bug.

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Declaration
I hereby declare that the project entitled “ACTIVE CELL PHONE
DETECTOR” submitted by us to T. John Institute of Technology,
Visvesvaraya Technological University during the degree of Bachelor of
Engineering in Electronics & Communication Engineering is a record of
bonafide project work carried out by us under the guidance of Mr.
Basavanagouda.
I further declare that the work reported in this mini project has not been
submitted & will not be submitted either in part or in full for award of any
degree in this institute.
SHAHRUKH JAVED
SYED MOULA

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Acknowledgement
The satisfaction that accompanies the successful completion of the
task would be put incomplete without the mention of the people who made
it possible, whose constant guidance and encouragement crown all the
efforts with success.
It is my greatest pleasure to thank Dr. Arun Vikas Singh Head of
Department of Electronics and Communication, T.John Institute of
Technology for providing us heart full encouragement support and
allowing us to work in such a resourceful lab of this esteemed institute &
thereby fulfilling one of my dreams.
I whole heartedly thank my project guide Mr. Basavanagouda (Asst.
Professor Electronics & Communication Department) for his consistent
guidance, expert academic and support throughout the project, without his
great concepts & inspiration it would have been impossible.
I‟m very much thankful to Mr.Chethan for his help in the laboratory for
practical guidance during this project.
I thank my parents for their emotional and financial support which they
provided during this project.
We show gratitude to our Honourable Principal Dr. H.N Thippeswamy,
for having provided all the facilities and support.
I thank to all faculties who directly and indirectly helped us in the
completion of this projects.

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INTRODUCTION
As increase in the technology in the world the most common electronic equipment
used is cell phones. With advancement in communication technology, the requirement
of cell phones has increased manifold. A cell phone typically transmits and receives
signals in the frequency range of 0.9 to 3GHz & operates by connecting to a cellular
network provided by a mobile phone operator, allowing access to the public telephone
network.
Here we will discuss the overview of Cell Phone Detector & further we will also
discuss about circuit diagram and description of the circuit diagram.
This handy, pocket-size mobile transmission detector can sense the presence of an
activated mobile cell phone from a distance of one and-a-half meters. So it can be
used to prevent use of mobile phones in examination halls, confidential rooms, etc. It
is also useful for detecting the use of mobile phone for Spying and unauthorized video
transmission.
The circuit can detect the incoming and outgoing calls, SMS and video transmission
even if the mobile phone is kept in the silent mode. The moment the Bug detects
RF(radio frequency) transmission signal from an activated mobile phone, it starts
sounding a beep alarm and the LED blinks. The alarm continues until the signal
transmission ceases.
Earlier there was no technology to detect cell phones in the restricted areas, in manual
checking there is still a chance of having cell phone by-mistake or if not checked
properly.
NOTE Circuit will not detect if the mobile is switched off.
This project provides a simple circuit to detect the presence of an activated cell phone
by detecting these signals.

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COMPONENTS USED
SR.NO. COMPONENT NAME SPECIFICATION QUANTITY
1. INTEGRATED CIRCIUT
CA3130
NE555
1
1
2. TRANSISTOR Bc548 1
3. RESISTOR
2.2MΩ
100KΩ
1KΩ
12KΩ
15KΩ
2
1
2
1
1
4. CAPACITOR
22pF
0.22uF
100u(16v)
47pF
0.1uF
0.01uF
4.7MF(16v)
2
1
1
1
2
1
1
5. BUZZER PIEZO 1
6. LED RED 1
7. ANTENNA 5” 1
8. BATTERY 9V 1
Table 1. List of the Components Used.

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MAJOR COMPONENT DESCRIPTION
1. CA310 IC
Fig 1. Pin configuration of IC CA3130
CA3130 are op amps that combine the advantage of both CMOS and bipolar transistors.
Gate-protected P-Channel MOSFET (PMOS) transistors are used in the input circuit to
provide very-high-input impedance, very-low-input current and exceptional speed
performance. The use of PMOS transistors in the input stage results in common-mode input-
voltage capability down to 0.5V below the negative-supply terminal, an important attribute in
single-supply applications.
A CMOS transistor-pair, capable of swinging the output voltage to within 10mV of either
supply-voltage terminal (at very high values of load impedance), is employed as the output
circuit.
The CA3130 Series circuits operate at supply voltages ranging from 5V to 16V, (±2.5V to
±8V). They can be phase compensated with a single external capacitor, and have terminals
for adjustment of offset voltage for applications requiring offset-null capability. Terminal
provisions are also made to permit strobing of the output stage.

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Absolute Maximum Ratings
DC Supply Voltage (Between V+ And V- Terminals) . .. . . . . .16V
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .8V
DC Input Voltage . . . . . . . . . . . . . . . . . . . . . ……………........ (V+ +8V) to (V- -0.5V)
Input-Terminal Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1mA
Output Short-Circuit Duration . . . . . . . . . . . . . . . ………...….Indefinite Operating
Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . …………. . . -50oC to 125oC
Features
1. Ideal for Single-Supply Applications.
2. Common-Mode Input-Voltage Range Includes Negative Supply Rail; Input Terminals
can be Swung 0.5V Below Negative Supply Rail.
3. CMOS Output Stage Permits Signal Swing to Either (or both) Supply Rails.
4. Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• Ground-Referenced Single Supply Amplifiers.
• Fast Sample-Hold Amplifiers.
• Long-Duration Timers/Monostables
• High-Input-Impedance Comparators & Wideband Amplifiers
• Voltage Followers & Voltage Regulators.
• Peak Detectors
• Single-Supply Full-Wave Precision Rectifiers
• Photo-Diode Sensor Amplifiers

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2. NE555 IC
Fig 2. Pin configuration of NE555 IC
The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation,
and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and
as a flip-flop element. Derivatives provide up to four timing circuits in one package.
These devices are precision timing circuits capable of producing accurate time delays or
oscillation.
In the time-delay or mono-stable mode of operation, the timed interval is controlled by a
single external resistor and capacitor network.
In the a-stable mode of operation, the frequency and duty cycle can be controlled
independently with two external resistors and a single external capacitor.
The threshold and trigger levels normally are two thirds and one-third, respectively, of VCC.
These levels can be altered by use of the control-voltage terminal. When the trigger input
falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input
is above the trigger level and the threshold input is above the threshold level, the flip flop is
reset and the output is low. The reset (RESET) input can override all other inputs and can be
used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the
output goes low. When the output is low, a low-impedance path is provided between
discharge (DISCH) and ground. The output circuit is capable of sinking or sourcing current
up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output
levels are compatible with TTL inputs.

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Pin description
The connection of the pins for a DIP package is as follows:
PIN NAME PURPOSE
1 GND Ground reference voltage, low level (0 V)
2 TRIG
OUT will be high as long as the trigger is kept at low voltage.
Output of the timer totally depends upon the amplitude of the
external trigger voltage applied to this pin.
3 OUT This output is driven to approximately 1.7 V below +VCC, or
to GND.
4 RESET
A timing interval may be reset by driving this input to GND,
but the timing does not begin again until RESET rises above
approximately 0.7 volts. Overrides TRIG which overrides
THR.
5 CTRL Provides "control" access to the internal voltage divider (by
default, 2/3 VCC).
6 THR The timing (OUT high) interval ends when the voltage at THR
("threshold") is greater than that at CTRL (2/3 VCC if CTRL is
open).
7 DIS Open collector output which may discharge a capacitor
between intervals. In phase with output.
8 VCC Positive supply voltage, which is usually between 3 and 15 V
depending on the variation.
Table 2.
Features
1. Timing From Microseconds to Hours
2. Astable or Monostable Operation
3. Adjustable Duty Cycle
4. TTL-Compatible Output Can Sink or Source Up to 200 mA
Applications
• Fingerprint Biometrics.
• Iris Biometrics.
• RFID Reader.
• Pulse width modulation.
• Precision timing and pulse generation.

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BLOCK DIAGRAM
Fig 3. Block diagram of circuit
There are four major blocks in the case of the cell phone detector. They are
○ Antenna ○ Current to voltage to converter
○ Monostable IC 555 ○ Output stage
Block Diagram and Working of Cell Phone Detector:
Ordinary LC (Coil-Capacitor) circuits are used to detect low frequency radiation in the AM
and FM bands. The tuned tank c1rcuit having 3 cm] and a variable capacitor retrieve the
signal from the carrier wave. But such LC circuits cannot detect high frequency waves near
the microwave region. Hence in the circuit a capacitor is used to detect RF from mobile
phone considering that a capacitor can store energy even from an outside source and oscillate
like LC circuit.

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CIRCUIT DIAGRAM
Fig4. Circuit diagram of cell phone detector
Circuit Diagram Description:
An ordinary RF detector using tuned LC circuits is not suitable for detecting signals in the
GHz frequency band used in mobile phones. The transmission frequency of mobile phones
ranges from 0.9 to 3 GHZ with a Wavelength of 3.3 to 10 cm.
So a circuit detecting gigahertz signals is required for a cell phone detector. Here the circuit
uses a 0.22pF disk capacitor C3 to capture the radio frequency (RF) signals from the mobile
phone. The disk capacitor along with the leads acts as a small gigahertz loop antenna to
collect the RF signals from the mobile phone.
Op amp IC CA3130 (IC1) is used in the circuit as a current to voltage converter with
capacitor 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. The output
CMOS transistor is capable of swinging the output voltage to within 10 mV of either supply
voltage terminal. 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 minute current to the inputs of IC1. This
will upset the balanced input of IC1 and convert the current into the corresponding output
voltage.

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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 IC-1 for
phase compensation and gain control to optimize the frequency response.
When the mobile phone signal is detected by C3, the output of IC-l becomes high and low
alternately according to the frequency of the signal as indicated by LED-1. This triggers
monostable timer IC-2 through capacitor C7. Capacitor C6 maintains the base bias of
transistor T1 for fast switching action. The low value timing components R6 and C9 produce
very short little delay to avoid audio nuisance.

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Advantage
 Easy to operate & Fast response.
 Smaller in size.
 Efficient design eliminates button operation.
 Low power consumption and sophisticated security.
 Detection of hidden cell phones.
Limitations of Mobile Phone Detector Circuit:
“RANGE” The prototype version has only limited range of 1 to 1.5 meters. But if a
preamplifier stage using JFET or MOSFET transistor is used as an interface between the
capacitor and IC, range can be increased.
Applications:
1. This circuit can be used at meetings to detect presence of mobile phones and prevent
the use of cell phones. With a GSM detector the use of mobile phones is detected, so
the visitor can be informed that this is not allowed.
2. It can be used for detecting mobile phones used for spying and unauthorized
transmission of audio and video.
3. It can be used to detect stolen mobile phones.
4. Colleges and Universities: During tests and exams the use of mobile phones is
prohibited, the students could use it to send answers among each other. By using a
GSM detector this kind of fraud is prohibited. The presence of a GSM Detector can
work in a preventing way, because when GSM detector is present, the use of mobile
phones does not stay unnoticed.
It is useful where the use of mobile phone is prohibited like:
○Petrol pumps. ○Gas station. ○Historical places.
○Religious places. ○Court of laws. ○Military bases.
○Hospitals. ○Conferences . ○Embassies.

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CONCLUSION
The project “ACTIVE CELL PHONE DETECTOR” was designed to help to detect
the misuse of communication for security reasons with the friendly hardware
interaction for the users. The working capability of a cell phone detector is appreciable
and can be operated very efficiently.
Secondly, integrating features of all the hardware components along with the
advanced IC‟s used contributed to the best working of the unit.
Thus in this project we made an attempt to design a mobile detector which can detect
both the incoming and outgoing calls as well as video transmission even if the mobile
is kept at the silent mode. Our circuit has detected the presence of an active mobile
phone even at a distance of about one and half a meter. It gave the indication of an
active mobile phone by glowing the LED, according to the receiving frequency and by
buzzing the sound of the buzzer. The alarm continues until the Signal is ceases.
Finally, the project has been successfully implemented & tested. It really persuades us
to do more and more perhaps in better way in future.