PREFACE

Project is important in the curriculum of engineering students. Its successful is very important.

The study remains incomplete without the practical knowledge. Theoretical knowledge is not sufficient so one requires practical knowledge too. It is rather important for every student to undertake a project.

These days in the competitive age having a different perspective providing a leading edge .Electronics projects provides insight to students about the way the work is done in industries. It helps in systematically aligning students with the work culture of the practical area.

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ACKNOWLEDGEMENT

Theoretical knowledge is never sufficient. What one learns, that has to be practically implemented. During these days, I have got to learn a lot practically, which otherwise would not have been possible. I took this opportunity to thank everybody, who have helped me in some or the other way in this task.

First of all I would like to thank my institution MJRP COLLEGE OF ENGINEERING & TECHNOLOGY (JAIPUR).

Next I would like to thank Ms. Jyoti Rawat and Ms. Kiran Rawat. For giving me a chance to work on this project. Working in such an organizations enhances several other skills along with the technical knowledge.

Most of all I am thankful to MR. VIPIN CHOUHAN (HOD, Electronics and comm.) who supported me a lot during project.

We would also like to thank many individuals who helped us directly or indirectly for spending their valuable time and giving me their guidance and insightful suggestion at all stages of our projects.

Last but not the least I thank all my friends who directly or indirectly helped me during this term.

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ABSTRACT

This report presents the design, implementation, and testing of a MOBILE SIGNAL DETECTOR & CELL PHONE JAMMER. This device works for GSM 900 mobile phones. This project will go through two phases:

PHASE ONE: In first phase of our project we decided to device the moile signal detection device that can detect the radio frequency moile signals of GSM 900 band. This device will work when it detects any mobile phone signal and act as an input to our second phase so that it can start jamming the mobile signals.

PHASE TWO: On completion of the first phase we will start working on it and will be establishing the system design and selecting suitable components and building the basic PCB layout design to implement the basic circuit functioning and mount the noise generator coil on the circuit in order to generate the noise signal so it could be amplified and transmitted to jam the required frequency band i.e. GSM 900 band.

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LIST OF FIGURES

S.No. FIG. No.

FIGURE NAME PAGE No.

1. 1.1 CIRCUIT DIAGRAM OF MOBILE DETECTOR 3

2. 4.1 INTERNAL BLOCK DIAAGRAM OF NE555 7

3. 4.2 CIRCUIT OF TIMER 555 AS MONOSTABLE MULTIVIBRATOR

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4. 4.3 TIMER OUTPUT WAVEFORMS 10

5. 4.4 TIMER OUTPUT OF ASTABLE MULTIVIBRATOR 11

6. 4.5 VIEW OF CA3130 13

7. 4.6 TRANSISTOR 14

8. 4.7 SYMBOL OF TRANSISTOR 14

9. 4.8 AMPLIFIER CIRCUIT 15

10. 4.9 SYMBOL OF LED 16

11. 4.10 CAPACITORS 18

12. 4.11 CERAMIC CAPACITOR 18

13. 4.12 ELECTROLYTE CAPACITORS 19

14. 4.13 RESISTOR 20

15. 4.14 BUZZER 21

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S.No. FIG. No.

FIGURE NAME Page No.

16. 4.15 PCB LAYOUT 23

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TABLE OF CONTENTS

INTRODUCTION TO PHASE ONE

S. No. CONTENTS PAGE No. 1.

2.

3. 4.

INTRODUCTION……………………………………1.1 METHODOLOGY

WORKING...................................................................

LIST OF COMPONENTS…………………………...

COMPONENTS DESCRIPTION4.1 NE555 4.1.1 FEATURES 4.1.2 APPLICATIONS 4.1.3 WORKING

4.2 IC CA3130 4.2.1 FEATURES 4.2.2 APPLICATIONS

4.3 TRANSISTOR-BC548 4..1 TRANSISTOR AS AN AMPLIFIER 4.4 LIGHT EMITTING DIODE

4.5 CAPACITORS 4.5.1 LIST OF CAPACITORS USED 4.5.2 TYPES OF CAPACITORS USED

4.6 RESISTORS

4.7 SWITCH4.8 BUZZEA

4.9 POWER SUPPLY

4.10 PCB

1-22

4-5

6

7-237888

111212

1415

16

171818

20

2121

21

22

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INTRODUCTION TO SECOND PHASE

S. No. CONTENTS PAGE No.

5.

6.

7.

8.

MOBILE JAMMER…………………………………5.1 DESCRIPTION5.2 MOBILE JAMMING TECHNIQUE 5.2.1 TYPE “A” DEVICE 5.2.2 TYPE “B” DEVICE 5.2.3 TYPE “C” DEVICE 5.2.4 TYPE “D” DEVICE 5.2.5 TYPE “E” DEVICE

OUR DEVICE………………………………………...

CNCLUSION………………………………………….

REFERENCES…………………………………………

24-282426-282626272728

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INTRODUCTION TO PHASE ONE

INTRODUCTION

The Mobile detection project is an advanced device which finds various applications in the modern fields of communication and surveillances. Mobile detection project is designed to detect the mobile phone in a closed room / place which is in active transmission mode. This project is very useful for the private meetings, defense establishment, military camp, Hospitals, petrol pumps etc., where the uses of an active Mobile Communication (GSM) device are prohibited. With the aid of the project, one can detect the active mobile device like Cell Phone and GPS systems. Here the mobile detection project can be used like a metal detector and the project is capable of detecting the Cell Phone like device from the range of few centimeters to few inches depending upon the cell phone’s transmission strength and other parameters. Here the project is waved near the person / place where the presence of a GSM is banned. Further, the project also incorporates a very unique feature of remote paging & indication. In this part when the project is installed on the frame of a door or entrance, (like metal detectors) it scan incoming person’s mobile activity and if the person is carrying an “Active” mobile phone, then instead of activating an alarm, it sends a wireless message using Infra-Red signal to a microcontroller unit which ic monitored by a person. So whenever the project detects the active phone carried by a person, it can be made to display an alert message about the same to watchman security personnel silently.

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1.1METHODOLOGY:

Here the project consists of a set of high sensitive electronic wave detection antenna, preamplifier, filter, Schmitt trigger, switching stage an alarm. The project is exactly same as that of a metal detector in principle and operation. The project is also similar to operation and detection like the Metal / Explosive detector, only with a difference being that, the Metal / Explosive detector is going to detect the passive parameters, but whereas the project is aimed to detect the active signals like GSM signal source like mobile phone which operates in the frequency band of 900 MHz or 1800 MHz typically.

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Fig 1.1 CIRCUIT DIAGRAM OF MOBILE DETECTOR

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WORKING

This handy, pocket-size mobile transmission detector can sense the presence of an activated mobile 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 moments the bug detects RF transmission signal from an activated mobile phone, it starts sending a beep alarm and the LED blinks. The alarm continues until the signal transmission ceases. 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. Fig. 1.1 shows the working of mobile detector so a circuit detecting GHz signals is required for a mobile bug. Here the circuit uses a 0.22µF disk capacitor (C3) to capture the RF signals from the mobile phone. The lead length of the capacitor is fixed as 18mm with a spacing of 8mm between the leads to get the desired frequency. The disk capacitor along with the leads acts as a small GHz. 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 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. The output CMOS transistor is capable of swinging the output voltage to within 10mV 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. 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 discharge path for capacitors C4. feedback resistor R3 makes the inverting input high when the output becomes high. Capacitor C5 (47pF) is connected across ‘strobe’ (Pin 8) an ‘null’ inputs (pin 1) of IC1 for phase

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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 for fast switching action. The low-value timing components R6 and C9 produce very short time delay to avoid audio nuisance. Assemble the circuit on a general purpose PCB as compact as possible and enclose in a small box like junk mobile case. As mentioned earlier, capacitor C3 should have a lead length of 18mm with lead spacing of 8mm. Carefully solder the capacitor in standing position with equal spacing of the leads. The response can be optimized by trimming the lead length of C3 for the desired frequency. You may use a short telescopic type antenna. Use the miniature 12V battery of a remote control and a small buzzer to make the gadget pocket-size. The unit will give the warning indication if someone uses mobile phone within a radius of 2 feet.

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LIST OF COMPONENTS

1. IC-CA31302. IC-NE5553. Transistor-BC5484. LED5. Capacitor6. Resistor7. Switch8. Buzzer9. 9V Power supply10. PCB

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COMPONENT DESCRIPTION

4.1 NE555:

The LM555/NE555/SA555 is a highly stable controller capable of produce accurate timing pulses. With monostable operation, the time delay is controlled by one external resistor and one capacitor. With astable operation, the frequency and duty cycle are accurately controlled with two external resistors and one capacitor.

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4.1.1 Features:

High Current Drive Capability (200mA) Adjustable Duty Cycle Temperature stability of 0.005%ºc Timing from Sec to Hours Turn off Time Less than 2Sec

4.1.2 Applications:

Precision Time Pulse Generation Time Delay Generation Sequential Timing

4.1.3 WORKING:

1. MONOSTABLE OPERATION :

In this mode, the timer generates a fixed pulse whenever the trigger voltage falls below vcc/3.When the trigger pulse voltage applied to the #2 pins falls below Vcc/3 while the timer output is low, the timer’s internal flip-flop turns the discharging Tr. Off and causes the timer output to become high by charging the external capacitor C1 and setting the flip-flop output at the same time. The voltage across the external capacitor C1, VC1 increases exponentially with the time constant t=RA*C and reaches 2Vcc/3 and td=1.1RA*C. Hence capacitor C1 is charged through resistor RA. The greater the time constant RAC controls the

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output pulse width. When the applied voltage to the capacitor C1 reaches 2Vcc/3, the comparator on the trigger terminal resets the flip-flops, turning the discharging Tr. On. At this time, C1 begins to discharge and the timer output converts to low.In this way, the timer operating in monostable repeats the above process. Fig 4.3 shows the time constant relationship based on RA and C. Fig 4.3 shows the general waveforms during monostable operation.It must be noted that, for normal operation, the trigger pulse voltage needs to maintain a minimum of Vcc/3 before the timer output turns low. That is, although the output remains unaffected even if a different trigger pulse is applied while the output is high, it may be affected and the waveform not operate properly f the trigger pulse voltage at the end of the output pulse remains at below Vcc/3. Fig 4.3 shows such timer output abnormality.

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2. ASTABLE OPERATION:

An astable timer operation is achieved by adding resistor RB and configuring it. In astable operation, the trigger terminal and the threshold terminal are connected so that a self-trigger is formed, operating as a multi vibrator. When the timer output is high, its internal discharging Tr. Turn off and the VC1 increases by exponential function with the time constant (RA+RB)*C.Fig 4.4 shows the Timer output waveform of astable multivibrator. When the VC1, or the threshold voltage, reaches 2Vcc/3, the comparator output on the trigger terminal becomes high, resetting the F/F and causing the timer output to become low. This in turn turns on the discharging Tr. And the C1 discharges through the discharging channel formed by RB and the discharging Tr. When the VC1 falls below Vcc/3, the comparator output on the trigger terminal becomes high and the timer output becomes high again. The discharging Tr. turns off and the VC1 rises again. In the above process, the section where the timer output is high is the time it

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takes for the VC1 to rise from Vcc/3 to 2Vcc/3, and the section where the timer output is low is the time it takes for the VC1 to drop from 2Vcc/3 to Vcc/3.

4.2 IC-CA3130

CA3130A and 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 at the output circuit.

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Fig 4.5 shows the view of IC CA-3130. 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. The CA3130 offers superior input characteristics over those of the CA3130.

4.2.1 FEATURES:

MOSFET Input Stage Provides Very High ZI=1.5TΩ (1.5×1012Ω) (Typ) Ideal for single-supply applications Common-Mode input-Voltage Range Includes Negative Supply Rail: Terminals can be swung 0.5V Below Negative Supply Rail CMOS Output Stage Permits Signal Swing to Either (or both) Supply Rails

4.2.2 APPLICATIONS:

Ground-Referenced Single Supply Amplifiers Fast Sample-Hold amplifiers Long-duration Timers/Monostables High-Input-Impedance Comparators (Ideal Interface with Digital CMOS) High-Input-Impedance Wideband Amplifiers Voltage Followers (e.g. Follower for Single Supply D/A Converter) Voltage Regulators (Permits Control of Output Voltage Down to 0V) Peak Detectors Single-Supply Full Wave Precision Rectifiers Photo-Diode Sensor Amplifiers

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4.3 TRNSISTOR-BC548

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A transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a 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. Some transistors are packaged individually but most are found in integrated circuits.The transistor symbol is shown in Fig 4.7. The transistor is fundamental building block of modern electronic devices, and its presence is ubiquitous in modern electronic systems.

4.3.1 TRANSISTOR AS AN AMPLIFIER:

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The basic amplifier circuit of transistor is shown in Fig 4.8. The common emitter amplifier is designed so that a small change in voltage in (Vin) changes the small current through the base of transistor and the transistor’s current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout. It is important that the operating values of the transistor are chosen and the circuit designed such that as far as possible the transistor operates with in linear portion of the graph, such as that shown between A and B, otherwise the output signal will suffer distortion. Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both. From mobile phones to television, vast number of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete transistor audio amplifiers barely supplied a new hundred mill watts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved.Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive.

4.4 LIGHT EMITTING DIODE:

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A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a practical electronic component in1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.

The LED is based on the semiconductor diode. When a diode is forward biased (switched on), electrons are able to recombine with holes within the device, releasing energy in the form of photons. This effect is called as electroluminescence and the color of light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is usually small in area (less than 1 mm), and integrated optical components are used to shape its radiation pattern and assist in reflection. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. However, they are relatively expensive and require more precise current and heat management than traditional light sources. Current LED products for general lighting are more expensive to buy than fluorescent lamp sources of comparable output. LED symbol shown in Fig 4.9.

They also enjoy use in applications as diverse as replacements for traditional light sources in automotive lighting (particularly indicators) and in traffic signals.The compact size of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are useful in advanced communications technology.4.5 CAPACITORS:

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A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). When a potential difference (voltage) exists across the conductors, an electric field is present in the dielectric. The field stores energy and produces a mechanical force between the conductors. The effect is greatest when there is a narrow separation between large areas of conductor hence capacitor conductors are often called plates.

An ideal capacitor is characterized by a single constant value, capacitance, which is measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them. In practice, the dielectric between the plates passes a small amount of leakage current. The conductors and leads introduce an equivalent series resistance and the dielectric has an electric field strength limit resulting in a breakdown voltage.

Capacitors are widely used in electronic circuits to block the flow of direct current while allowing alternating current to pass, to filter out interference, to smooth the output of power supplies, and for many other purposes. They are used in resonant circuits in radio frequency equipment to select particular frequencies from a signal with many frequencies. Fig 4.10 shows the capacitors used.

4.5.1 LIST OF CAPACITORS USED:

S.NO. CAPACITANCE QUANTITY1. 22PF 22. 0.22µF 13. 100µF 14. 47pF 15. 0.1µF 36. 4.7µF 1

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4.5.2 TYPES OF CAPACITOR USED:

1. CERAMIC CAPACITOR:

A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). When a potential difference (voltage) exists across the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the conductors.The effect is greatest when there is narrow separation between large areas of conductor hence capacitor conductors are often called plates.

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An ideal capacitor is characterized by a single constant value, capacitance, which is measured in farads. This is the ratio of electric charge on each conductor to the potential difference between them. In practice, the dielectric between the plates passes a small amount of leakage current. The conductors and leads introduce an equivalent series resistance and the dielectric has an electric field strength limit resulting in a breakdown voltage.

Capacitors are widely used in electronic circuits to block the flow of direct current while allowing alternating current to pass, to filter out interference, to smooth the output of power supplies, and for many other purposes. They are used in resonant circuits in radio frequency equipment to select particular frequencies from a signalwith many frequencies.

2. ELECTROLYTE CAPACITOR :

An electrolytic capacitor is a type of capacitor that uses an ionic conducting liquid as one of its plates with a larger capacitance per unit volume than other type. They are valuable n relatively high-current and low-frequency electrical circuits. This is especially the case in power-supply filters, where they store charge needed to moderate output voltage and current fluctuations in rectifier output. They are also widely used as coupling capacitors in circuits where AC should be conducted but DC should not.

Electrolytic capacitors can have a very high capacitance, allowing filters made with them to have very low corner frequencies. 4.6 RESISTORS:

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A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm’s law:

V = IR

Resistors are 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).

The primary characteristics of a resistor are the resistance, the tolerance, maximum working voltage and the power rating. Other characteristics include temperature coefficient, noise, and inductance. Less well-known is critical resistance, the value below which power dissipation limits the maximum permitted current flow, and above which the limit is applied voltage. Critical resistance depends upon the materials constituting the resistor as well as its physical dimensions; it’s determined by design.

Resistors can be integrated into hybrid and printed circuits, as well as integrated circuits. Size, and position of leads (or terminals) are relevant to equipment designers; resistors must me physically large enough not to overheat when dissipating their power.

4.7 SWITCH

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A switch is an electrical component which can break an electrical circuit, interrupting the current or diverting it from one conductor to another.

4.8 BUZZER:

A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as microwave ovens, or game shows.

It most commonly consists of a number of switches or sensors connected to a control unit that determines if and which button was pushed or a preset time has lapsed, and usually illuminates a light on the appropriate button or control panel, and sounds a warning in the form of a continuous or intermittent buzzing or beeping sound.

Initially this device was based on an electromechanical system which was identical to an electric bell without the metal gong (which makes the ringing noise). Often these units were anchored to a wall or ceiling and used the ceiling or wall as a sounding board. Another implementation with some AC-connected device was to implement a circuit to make the AC current into a noise loud enough to drive a loudspeaker and hook this circuit up to an 8-ohm speaker. Now a days, it is not popular to use a ceramic-based piezoelectric sounder which makes a high-pitched tone. Usually these were hooked up to “driver” circuits which varied the pitch of the sound or pulsed the sound on and off.

4.9 POWER SUPPLY:

We used a 9 V battery as the power supply.4.10 PCB:

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The PCB layout is shown in Fig 4.15. PCB stands for printed circuit board which is used for wiring up of the components of a circuits. PCBs are made made of paper phenolic FR2 grade (low cost, for low frequency and low power circuit assembly) and glass epoxy FR4 grade (for high frequency, high power circuits) copper clade laminates (available in 1.6 mm, 2.4mm and 3.6mm thickness). Single sided PCBs have copper foil only on one side while double-sided PCBs have copper foil on both side of laminate. Thickness of copper foil is 35 micrometer minimum on cheaper PCBs and 70 micrometer on slightly costlier PCBs. Tracks (conductive paths) are made by masking (converting) the track part of copper with etch-resist enamel paint (you can even use nail polish) and later dipping the laminate in ferric chloride solutions to dissolve all copper except under the mask part. Holes in PCBs are drilled after etching is over. The track on two sides of a PCB are joined using printed through hole (PTH) techniques, which is equivalent to using slotted copper rivets for joining tracks on both sides. On cheaper PCBs, PTH are not provided, only Pads (i.e. circular copper land with centre hole) are provided and you have to join the tracks on both sides by soldering a copper wire to the pads with a copper wire. In single sided PCB components are mounted on the side which has no track (called component side). In a double-sided PCB the component side is defined (marked before hand) or it will show component outline (also called silk screen) green masking is the process of applying a layer of green color insulation vanish on all parts of tracks except near the holes, to protect the tracks from exposure to atmosphere and thus prolong its life and reliability.

PCB LAYOUT

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A BRIEF INTRODUCTION TO SECOND PHASE

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MOBILE JAMMER

5.1 DESCRIPTION

A mobile phone jammer is an instrument used to prevent cellular phones from receiving signals from or transmitting signals to base stations. When used, the jammer effectively disables cellular phones. These device can be used in practically any location, but are found primarily in places where a phone call would be particularly disruptive because silence is expected. As with other radio jamming, cell phone jammers block cell phone use by sending out radio waves along the same frequencies that cellular phones use. This causes enough interference with the communication between cell phones and towers to render the phones unusable. On most retail phones, the network would simply appear out of range. Most cell phones use different bands to send and receive communications from towers (called full duplexing). Jammers can work by either disrupting phone to tower frequencies or tower to phone frequencies. Smaller handheld models block all bands from 800 MHz to 1900 MHz within a 30-foot range (9 meters). Small devices tend to use the former method, while larger more expensive models may interfere directly with the tower. The radius of cell phone jammers can range from a dozen feet for pocket models to kilometers for more dedicated units. The TRJ-89 jammer can block cellular communications for a 5-mile (8 km) radius.Older jammers sometimes were limited to working on phones using only analog or older digital mobile phone standards. Newer models such as the double and triple band jammers can block all widely used systems (CDMA, GSM, et al.) and are even very effective against newer phones which hope to different frequencies used for mobile phones vary worldwide, some work only in specific regions such as Europe or North America.The jammer’s can effect vary widely based on factors such as proximity to towers, indoor and outdoor settings, presence of buildings and landscape, even temperature and humidity play a role.There are concerns that crudely designed jammers may disrupt the functioning of medical devices in common use operate at low enough power output (<1W) to avoid causing any problems.Jamming is the (usually deliberate) transmission of radio signals that disrupt communications by decreasing the signals to noise ratio. Unintentional jamming occurs when an operator transmits on a busy frequency without checking that it is in use first, or without being able to hear distant stations on the same frequency.

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Another form of unintentional jamming occurs when equipment accidentally radiates a signal, such as a cable TV plant that accidentally emits on an aircraft emergency frequency.When these various waves hit at the same time to each other then a propagation is generated which disturbs the network of the cell phone nearby, as that equipment is also using some kind of frequency to run itself.Intentional communications jamming is usually aimed at radio signals to disrupt control of a battle. A transmitter, tuned to the same frequency as the opponents receiving equipment and with the same type of modulation, can with enough power override any signal at the receiver.The most common types of this form of signal jamming are random noise, random pulse, stepped tones, warbler, random keyed modulated CW, tone, rotary, pulse, spark, recorded sounds, gulls, and sweep through. These can be divided into two groups- obvious and subtle.

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5.2 MOBILE JAMMING TECHNIQUES:

There are different approaches to prevent mobile phones from ringing in specific area, the main five approaches used, these techniques are summarized in this section:

5.2.1 Type “A” Device:

In this device we overpower cell phone’s signal with a stronger signal, this type of device comes equipped with several independent oscillators transmitting ‘jamming signals’ capable of blocking frequencies used by paging devices as well as those used by cellular/PCS systems control channels for call establishment.When active in a designated area, such devices will (by means of RF interference) prevent all pagers and mobile phones located in that area from receiving and transmitting calls. This type of device transmits only a jamming signal has very poor frequency selectivity, which leads to interference with a larger amount of communication spectrum than it was originally intended to target.Technologist Jim Mahan said, “There are two types. One is called brute force jamming, which just block everything. The problem is , it’s like power-washing the airwaves and it bleeds over into the public broadcast area. The other puts out a small amount of interference, and you could potentially confine it within a single cell block. You could use of lots of small jamming to keep a facility under control”.

5.2.2 Type “B” Device:

This device also called “Intelligent Cellular Disablers devices”, and it does not transmit an interfering signal on the control channels. The device basically works as a detector, and it capable to communicate with the cellular base station. When the device detects the presence of a mobile phone in the “silent” room; a prevention of authorization of call establishment is done by the software at the base station. The device signals the base station that the target user is in a ‘quiet’ room; therefore, do not establish the communication. Message can be routed to the user’s voice-mail box, if the user subscribes to a voice-mail service. This process of detection and interruption of call establishment is done during the interval normally reserved for signaling and handshaking.

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This intelligent device as its name imply can recognize emergency calls and also can allow specific pre-registered users to use their mobile phones for a specified duration. Although this device sounds the best solution for disabling mobile phone, a provision is needed by the cellular/PCS service providers or provision by a third-party working cooperatively with full support of the cellular/PCS service providers, allowing the detector device to be integral part of the cellular/PCS systems.

5.2.3 Type “C” Device:

This device is also called “Intelligent Beacon Disablers”, as in the type “B” device it does not transmit an interfering signal on the control channels.The device, when located in a specific “silent” room, functions as a ‘beacon’ and any compatible terminal is ordered to disable its ringer or disable its operation. In the coverage area of the beacon only terminals which have a compatible receiver would respond and this should be built on a separate technology from cellular/PCS, for example Bluetooth technology. Also the handset must re-enable its normal function as it leaves the coverage area of the beacon.The need for intelligent handsets with a separate receiver for the beacon receiver from the cellular/PCS receiver, make effective deployment for the type “C” device will be problematic for many years.

5.2.4 Type “D” Device:

This jammer is similar to type “A”, but with a receiver, so that jammer is predominantly in receive mode and when the device detects the presence of a mobile phone in the “silent” room; it will be intelligently chose to interact and block the cell phone by transmitting jamming signal. This jam signal would only stay on as long as the mobile continues to make a link with the base station; otherwise there would be no jamming transmission.Thus the device much less electromagnetic pollution in terms of raw power transmitted and frequency spectrum from the type “A” Jammer, and therefore much less disruptive to passing traffic. This technique could be implemented without cooperation from PCS/cellular providers. Also this technique has an added

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advantage over Type B in that no added overhead time or effort is spent negotiating with the cellular network.

5.2.5 Type “E” Device:

This technique is using EMI suppression techniques to make a room into what is called a Faraday cage. Although labour intensive to construct, the Faraday cage essentially blocks, or greatly attenuates, virtually all electromagnetic radiation from entering or leaving the cage or in this case a target room.

With current advances in EMI shielding techniques and commercially available products one could conceivably implement this into the architecture of newly designed buildings for so-called “quiet-conference” rooms.

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OUR DEVICE

We have planned to build a type B jamming device. Since in our device in the first phase we have detected the mobile signal and the detector has started to detect the incoming signal and has started to produce the required signal that will act as an input to the second module device. So in our design the jamming will be enabled when detection of the signal has been done by our detector. This device is very useful at places where mobile phones are banned especially at confidential places. It can also be used to catch spies and when some kind of meeting are going on where mobile mobile phone are not allowed for example military, government meetings.

After completion of the first phase we have started working on this phase and have developed the basic circuit required for the mobile jammer.

We also have developed the initial circuit that we have with us in which we will mount the noise generation coil that will generate the required noise signal that will be amplified and then will be transmitted into the atmosphere so that we will introduce noise into the GSM 900 band.

As a result the mobile phone will be unable to detect the signals and will be jammed fulfilling our objective.

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CONCLUSION

After the completion of first phase of our project we can see that the mobile detection device is very useful equipment that can be used at a number of places and can be very useful for the society.

We implemented our project according to following plan:

1. We started by studying the basic need of a mobile detection and jamming device.

2. Then we gathered the required components for the completion of our first phase of the project according to the circuit.

3. The PCB layout was made and the required PCB was fabricated.4. After this the components were mounted on it and testing was done.5. Our design ran as per our expectation and was able to detect mobile signal.

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REFERENCES

1. Study of 8051, http://www.8051projects.info/2. Circuit diagram of mobile detector, http://electroschematics.com/wp-

content/uploads/2009/01/cellphone-detector3. Working of Mobile Detector, http://electroschematics.com/detectors/mobile

phone sniffer gsm telephonedetector/#p4/4. Study of 555

TimerIC,http://555%20timer%20IC%20wikipedia,%20the%20free%20encyclopedia.htm

5. Study of jamming Techniques, http://www.rapid4search.com/mobile detection and jamming techniques/pg268/en

6. GSM, Qing-An Zeng, Introduction to wireless and mobile systems,2003, Thomsons brooks/cole,pg224,228

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