CELL PHONE JAMMER

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CELL PHONE JAMMER

  1. 1. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 1VISVESVARAYA TECHNOLOGICAL UNIVERSITYBELGAUM-590014Dissertation Report on“CELL PHONE JAMMER WITH PRESCHEDULED TIMEDURATION”Submitted in partial fulfillment of the requirements for the award of degreeBACHELOR OF ENGINEERINGINELECTRONICS AND COMMUNICATION ENGINEERINGBYCHETHAN KUMAR S.N. 4GH09EC010GANESH M. 4GH10EC402MANU M. 4GH09EC027SRINIVAS H.V. 4GH09EC046Under the guidance ofMrs. BABY H.T. B.E., M.Tech,Associate professorDepartment of E&CE,GEC, HASSAN-573201Department of Electronics and Communication EngineeringGOVERNMENT ENGINEERING COLLEGEDAIRY CIRCLE, HASSAN-5732012012-2013
  2. 2. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 2GOVERNMENT ENGINEERING COLLEGEDairy circle, Hassan-573 201Department of Electronics & Communication EngineeringCERTIFICATECertified that the project work entitled “CELL PHONE JAMMER WITHPRESCHEDULED TIME DURATION” is a bonafide work carried out byMr. CHETHAN KUMAR S.N (4GH09EC010)Mr. GANESH M (4GH10EC402)Mr. MANU M (4GH09EC027)Mr. SRINIVAS H.V (4GH09EC046)in partial fulfillment for the award of degree of Bachelor of Engineering in Electronicsand Communication Engineering of the Visvesvaraya Technological University, JnanaSangama, Belgaum-590014 during the year 2012-2013. It is certified that, allcorrections/suggestions indicated for internal assessment have been incorporated in thereport. The project report has been approved as it satisfies the academic requirements withrespect of Project work prescribed for the mentioned degree.Internal guide: Head of dept.: Principal:Mrs. Baby H.T Dr. Paramesha Dr. KarisiddappaAssociate Professor Professor GECH.Dept. of ECE Dept. of ECEGECH. GECH.
  3. 3. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 3ABSTRACTMobile jammer is used to prevent mobile phones from receiving or transmitting signalswith the base stations. Mobile jammers effectively disable mobile phones within thedefined regulated zones without causing any interference to other communication means.Mobile jammers can be used in practically any location, but are used in places where aphone call would be particularly disruptive like temples, libraries, hospitals, cinema halls,schools & colleges etc.As with other radio jamming, mobile jammers block mobile phone use by sending outradio waves along the same frequencies that mobile phones use. This causes enoughinterference with the communication between mobile phones and communicating towers torender the phones unusable. Upon activating mobile jammers, all mobile phones willindicate "NO NETWORK‖. Incoming calls are blocked as if the mobile phone were off.When the mobile jammers are turned off, all mobile phones will automatically re-establishcommunications and provide full service.Mobile Jammers were originally developed for law enforcement and the military tointerrupt communications by criminals and terrorists to foil the use of certain remotelydetonated explosives. The civilian applications were apparent with growing publicresentment over usage of mobile phones in public areas on the rise & reckless invasion ofprivacy. Over time many companies originally contracted to design mobile jammers forgovernment switched over to sell these devices to private entities.
  4. 4. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 4ACKNOWLEDGEMENTSThe satisfaction and euphoria that accompany the successful completion of any task wouldbe incomplete without mentioning the people who have made it possible, because “successis the epitome of hard work and perseverance but stead-fast of all is encouragingguidance”. So with deep gratitude we acknowledge all distinguished personalities whoseguidance and encouragement served as bacon light and crowned our efforts with success.We wish to express our thanks to our beloved Principal, Dr. KARISIDDAPPA, for hisencouragement throughout our studies.At the outset we express our most sincere grateful thanks to Dr. PARAMESHA, HODand Professor, department of Electronics and Communication Engineering, for hiscontinuous support and advice not only during the course of our project but also during ourstay in GECH.We express our warm gratitude towards project co-ordinator and also being our seminarguide, Mrs. BABY H.T Associate Professor, department of Electronics andCommunication Engineering, for her guidance, encouragement and support throughout ourproject work.We also gratefully thank holy sanctum “GOVERNMENT ENGINEERING COLLEGE,HASSAN” the temple of learning, for giving us an opportunity to pursue the degree coursein Electronics and Communication Engineering thus help in shaping our career.Finally, we express our thanks to all our teaching and non-teaching staff of thedepartment of Electronics and Communication Engineering, our fellow classmatesand our parents for their timely support and suggestions in completing our task well intime. We thank once again to one and all who have been helped us in one or the other wayin completing our project in time.
  5. 5. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 5CONTENTSAbstract iAcknowledgments iiTable of Contents iiiList of figures vList of table‘s viiCHAPTER 1 PREAMBLE 1-31.1 Introduction 11.2 Objective of the project 21.3 Literature survey 21.4 Methodologies 5CHAPTER 2 PROJECT OVERVIEW 6-112.1 Block diagram 62.2 Description of block diagram 7CHAPTER 3 OPERATION OF CELL PHONE JAMMER 12-213.1 Mobile jamming techniques 143.2 Mobile jamming requirements 18CHAPTER 4 HARDWARE IMPLEMENTATION 22-484.1 Circuit diagram 224.2 Regulated power supply 234.3 Microcontroller (PIC16F877A) 26
  6. 6. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 64.4 Relay 324.5 LCD display 344.6 Cell phone jammer schematic 37CHAPTER 5 SOFTWARE IMPLEMENTATION 49-715.1 Flow chart 495.2 Source code 55CHAPTER 6 TESTING AND RESULTS 72-76CHAPTER 7 ADVANTAGES AND DISADVANTAGES 77CHAPTER 8 APPLICATIONS 78CONCLUSION 80REFRENCES 81
  7. 7. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 7LIST OF FIGURESFIGURE NAME PAGE NO.Figure 2.1 Block diagram of jammer with controller 6Figure 2.2 Jammer block diagram 7Figure 3.1 Signal handed from tower to tower 13Figure 3.2 Denial of service attack 14Figure 4.1 Circuit diagram of cell phone jammer 22Figure 4.2 Regulated power supply IC 24Figure 4.3 Bias connection of a three – terminal voltageregulator IC to a load 25Figure 4.4 Block diagram of power supply 26Figure 4.5 Pin configuration of PIC16F877A 30Figure 4.6 Basic relay switch and relay frames 32Figure 4.7 Relay with its coil and switch contacts 33Figure 4.8 2x16 line alphanumeric LCD display 34Figure 4.9 Pin description of LCD display 35Figure 4.10 LCD interface to microcontroller 36Figure 4.11 Cell phone jammer schematic 37Figure 4.12 Power supply unit 38Figure 4.13 Block diagram of IF section 39Figure 4.14 Simple function generator circuit 40Figure 4.15 Op – amp summer circuit 41Figure 4.16 Positive diode – clamper with bias 41Figure 4.17 Block diagram of RF section 42Figure 4.18 Pin diagram of MAXIM 44Figure 4.19 MAXIM 2623 Pin connection 45
  8. 8. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 8Figure 4.20 Typical biasing configuration for the MAR – 4SM 46Figure 4.21 T – Network attenuator 47Figure 4.22 Monopole antenna 48Figure 4.23 Antenna patterns 48Figure 6.1 Control toggle switches 72Figure 6.2 Control switch to select network 73Figure 6.3 Control switch to set time duration 73Figure 6.4 Control switch to run the jammer 74Figure 6.5 Jammer running stage on LCD display 74Figure 6.6 Signal ON jammer OFF 75Figure 6.7 Jammer ON signal OFF 76
  9. 9. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 9LIST OF TABLESTABLE NAME PAGE NO.Table 3.1 Comparison between jammer/disablerstechniques 18Table 3.2 GSM, DCS and 3G frequency band 20Table 4.1 Input/output ports 29
  10. 10. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 10CHAPTER 1PREAMBLE1.1 INTRODUCTIONCell phones are everywhere these days. It‘s great to be able to call anyone at any time.Unfortunately, restaurants, movie theaters, concerts, shopping malls and churches all sufferfrom the spread of cell phones because not all cell-phone users know when to stop talkingwhile most of us just grumble and move on, some people are actually going to extremes toretaliate.Disrupting a cell phone is the same as jamming any other type of radio communication. Acell phone works by communicating with its service network through a cell tower or basestation. Cell towers divide a city into small areas, or cells. As a cell-phone user drivesdown the street, the signal is handed from tower to tower A jamming devicetransmits on the same radio frequencies as the cell phone, disrupting the communicationbetween the phone and the cellphone base station in the tower Jamming devices overpowerthe cell phone by transmitting a signal on the same frequency and at a high enough powerthat the two signals collide and cancel each other out.Cell phones are full-duplex devices, which mean they use two separate frequencies, one fortalking and one for listening simultaneously. Some jammers block only one of thefrequencies used by cell phones; some has the effect of blocking both. The phone is trickedinto thinking there is no service because it can receive only one of the frequencies. Lesscomplex devices block only one group of frequencies, while sophisticated jammers canblock several types of networks at once to head off dual-mode or tri-mode phones thatautomatically switch among different network types to find an open signal.To jam a cell phone, all you need is a device that broadcasts on the correct frequencies.Although different cellular systems process signals differently, all cell-phone networks useradio signals that can be interrupted. GSM, used in digital cellular and PCS-based systems,
  11. 11. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 11Operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the 1900-MHz(sometimes referred to as 1.9-GHz) band in the United States. Jammers can broadcast onany frequency and are effective against CDMA, GSM and DCS. Old-fashioned analog cellphones and todays digital devices are equally susceptible to jamming.The actual range of the jammer depends on its power and the local environment, whichmay include hills or walls of a building that block the jamming signal. Low-poweredjammers block calls in a range of about 13 feet (~4 m). Higher-powered units create a cell-free zone as large as a football field. Units used by law enforcement can shut down serviceup to 1 mile (1.6 km) from the device.1.2 OBJECTIVE OF THE PROJECTHere our main intention is to block the signals of mobile phone using mobile phone signaljammer for prescheduled time duration using real time clock controlled by microcontroller.Switches are used to set the time for start and stop of jammer.1.3 LITERATURE SURVEY1.3.1 History of jammersThe technique used in most of the commercial jammers is based on noise attack. In thepreviously designed cell-phone jammers, designers came up with an electronic device thatacts as a transmitter to transmit electromagnetic signals of respective frequency and higherpower as used by GSM/DCS systems. In this technique voltage controlled oscillator (VCO)plays a major role in generating the jamming frequency. In our research we found that theabove technique is complex one as compared to our technique because our idea of jammingthrough spectrum distortion proves to be simpler, easier to fabricate and cost effective [1].The rapid proliferation of cell phones at the beginning of the 21st century to nearubiquitous status eventually raised problems, such as their potential use to invade privacyor contribute to academic cheating. In addition, public backlash was growing against thedisruption cell phones introduced in daily life. While older analog cell phones oftensuffered from poor reception and could even be disconnected by simple interference such
  12. 12. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 12as high frequency noise, increasingly sophisticated digital phones have led to moreelaborate counters.Cell phone jamming devices are an alternative to more expensive measures against cellphones, such as Faraday cages, which are mostly suitable as built in protection forstructures. They were originally developed for law enforcement and the military tointerrupt communications by criminals and terrorists. Some were also designed to foil theuse of certain remotely detonated explosives. The civilian applications were apparent, soover time many companies originally contracted to design jammers for government useswitched over to sell these devices to private entities. Since then, there has been a slow butsteady increase in their purchase and use, especially in major metropolitan areas [2].Disrupting a cell phone is the same as jamming any other type of radio communication.A cell phone works by communicating with its service network through a cell tower orbase station. Cell towers divide a city into small areas, or cells. As a cell-phone user drivesdown the street, the signal is handed from tower to tower A jamming devicetransmits on the same radio frequencies as the cell phone, disrupting the communicationbetween the phone and the cellphone base station in the tower Jamming devices overpowerthe cell phone by transmitting a signal on the same frequency and at a high enough powerthat the two signals collide and cancel each other out [5].In our research we found that the above technique is complex one as compared to ourtechnique because our idea of jamming through spectrum distortion proves to be simpler,easier to fabricate and cost effective.In our project we can jam the GSM, DCS and CDMA signals at a time. We can selectanyone system individually like GSM or DCS or CDMA which also includes aprescheduled timer, by which we can set the duration of jamming of signals. The maximumtime duration will be half an hour [6] [7].
  13. 13. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 131.3.2 PIC16F877A MicrocontrollerA PIC microcontroller is an application specific integrated circuit (ASIC) thatfetches and executes instructions based on input from some user program. Thesedevices do not have a fixed function, but rather are controlled by software [3].PIC is a family of architecture microcontrollers made by Microchip Technology, derivedfrom the PIC1650 originally developed by General Instruments Microelectronics Division.The name PIC initially referred to "Peripheral Interface Controller". PICs are popularwith both industrial developers and hobbyists alike due to their low cost, wide availability,large user base, extensive collection of application notes, availability of low cost or freedevelopment tools, and serial programming (and re-programming with flash memory)capability. The PIC16FXX series has more advanced and developed features whencompared to its previous series [8].1.3.3 Embedded systemThe C programming language is a general-purpose programming language that providescode efficiency, elements of structured programming, and a rich set of operators. Itsgenerality combined with its absence of restrictions, makes C a convenient and effectiveprogramming solution for a wide variety of software tasks. Many applications can besolved more easily and efficiently with C than with other more specialized languages Cx51is not a universal C compiler adapted for the target. It is a ground- up implementationdedicated to generating extremely fast and compact code. Cx51 provides you with theflexibility of programming in C and the code efficiency and speed of assembly language.The C language on its own is not capable of performing operations (such as input andoutput) that would normally require intervention from the operating system. Instead, thesecapabilities are provided as the part of the standard library. Because these functions areseparate from the language itself, C is especially suited for producing code that is portableacross a wide number of platforms.Since Cx51 is a cross compiler, some aspects of the C programming language and standardlibraries are altered or enhanced to address the peculiarities of an embedded targetprocessor [4] [9].
  14. 14. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 141.3.4 Mikro C compilerThe Mikro C PRO for PIC is a powerful, feature-rich development tool for PICmicrocontrollers. It is designed to provide the programmer with the easiest possiblesolution to developing applications for embedded systems, without compromisingperformance or control.Mikro C PRO for PIC is a full-featured ANSI C compiler for PIC devices from Microchip.It is the best solution for developing code for PIC devices. It features intuitive IDE,powerful compiler with advanced optimizations, lots of hardware and software libraries,and additional tools that will help to work. Compiler comes with comprehensive help fileand lots of ready-to-use examples designed to get started in no time. Compiler licenseincludes free upgrades and a product lifetime tech support.Mikro C PRO for PIC provides plenty of examples to expand, develop, and use as buildingbricks in your projects. Copy them entirely if you deem fit – that‘s why we included themwith the compiler [10].1.4 METHODOLOGIESHardware used in the project:i. Power supply board.ii. Switches board.iii. Microcontroller.iv. RTC.v. Relay circuit.vi. Jammer.Software used in the project:i. Embedded ‗C‘ programming.ii. Mikro C compiler.
  15. 15. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 15CHAPTER 2PROJECT OVERVIEWIn Cell phone jammer we can have various blocks like control switch set, LCD, RPS etc.,each block has its own functions. Heart of the project is jammer block, which is explainedin subsequent chapters. The various blocks of cell phone jammer and controller is asshown in Figure 2.1.2.1 BLOCK DIAGRAMRFigure 2.1: Block diagram of jammer with controllerPIC16F877A16×2 LCDDISPLAYCRYSTALOSCILLATORJAMMERBLOCKRELAYTRANSISTORDRIVER CIRCUITBACKUPBATTERYCRYSTALOSCILLATORCONTORLSWITCH SETRESETCIRCUITONCHIPRTCREGULATEDPOWER SUPPLY
  16. 16. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 16The various blocks of cell phone jammer is shown in below Figure 2.2.Figure 2.2 : Jammer block diagram2.2 DESCRIPTION OF BLOCK DIAGRAMThe main parts of this schematic diagram are:1) REGULATED POWER SUPPLY.2) MICROCONTROLLER (PIC16F877A)3) CRYSTAL OSCILLATOR4) ON CHIP RTC5) LCD DISPLAY6) TRANSISTOR DRIVER CIRCUIT7) RELAY8) JAMMER BLOCK9) CONTROL SWITCH SET10) RESET CIRCUIT2.2.1 Regulated power supplyA variable regulated power supply block shown in Figure 2.1, is also called a variablebench power supply, is one where one can continuously adjust the output voltage as perthe requirements. Most digital logic circuits and processors need a 5 volt power supply.POWERSUPPLYIFSECTIONRFSECTIONRFJAMMIGSIGNAL
  17. 17. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 17To use these parts we need to build a regulated 5 volt source. To make a 5 volt powersupply, we use a LM7805 voltage regulator IC. The LM7805 is simple to use. Circuitfeatures are as follow:i. 7805 is a 5V fixed three terminal positive voltage regulators IC.ii. The IC has features such as safe operating area protection, thermal shut down,internal current limiting which makes the IC very rugged.iii.Output currents up to 1A can be drawn from the IC provided that there is a properheat sink.2.2.2 Microcontroller (PIC16F877A)Peripheral Interface Controllers (PIC) is one of the advanced microcontrollers developedby microchip technologies. These microcontrollers are widely used in modern electronicsapplications. A PIC controller integrates all type of advanced interfacing ports andmemory modules. The first PIC chip was announced in 1975 (PIC1650). As like normalmicrocontroller, the PIC chip also combines a microcontroller unit called CPU and isintegrated with various types of memory modules (RAM, ROM, EEPROM, etc), I/Oports, timers/counters, communication ports, etc.All PIC microcontroller family uses Harvard architecture. This architecture has theprogram and data accessed from separate memories so the device has a program memorybus and a data memory bus (more than 8 lines in a normal bus). This improves thebandwidth (data throughput) over traditional von Neumann architecture where programand data are fetched from the same memory (accesses over the same bus). Separatingprogram and data memory further allows instructions to be sized differently than the 8-bitwide data word.PIC16F877A is one of the most advanced microcontrollers from Microchip. Thiscontroller is widely used for experimental and modern applications because of its lowprice, wide range of applications, high quality, and ease of availability.
  18. 18. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 182.2.3 Crystal oscillatorCrystal oscillator is made up of quartz crystal with the desired value of resonantfrequency forms part of the frequency-selective feedback network. Crystal oscillator isthe natural choice when the accuracy and stability of frequency. Crystal oscillator outputfrequency is stable to temperature range of -400C to +800C.2.2.4 On chip RTCThe real time clock (RTC) is a widely used device that provides accurate time and datefor many applications. The RTC chip present in the PC provides time components ofhour, minute and second. The RTC chip uses an internal battery that keeps the time anddate even when the power is off. One of the most widely used RTC chips is the DS1307from Dallas semiconductor.2.2.5 LCD screenLCD screen consists of two lines with 16 characters each. Each character consists of5x7dot matrix. Contrast on display depends on the power supply voltage and whethermessages are displayed in one or two lines. For that reason, variable voltage 0-Vdd isapplied on pin marked as Vee. Trimmer potentiometer is usually used for that purpose.Some versions of displays have built in backlight (blue or green diodes). When usedduring operating, a resistor for current limitation should be used (like with any LE diode).2.2.6 Transistor driver circuitAn SPDT relay consists of five pins, two for the magnetic coil, one as the commonterminal and the last pins as normally connected pin and normally closed pin. When thecurrent flows through this coil, the coil gets energized. Initially when the coil is notenergized, there will be a connection between the common terminal and normally closedpin. But when the coil is energized, this connection breaks and a new connectionbetween the common terminal and normally open pin will be established. Thus whenthere is an input from the microcontroller to the relay, the relay will be switched on. Thuswhen the relay is on, it can drive the loads connected between the common terminals andnormally open pin. Therefore, the relay takes 5V from the microcontroller and drives the
  19. 19. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 19loads which consume high currents. Thus the relay acts as an isolation device. Digitalsystems and microcontroller pins lack sufficient current to drive the relay. While therelay‘s coil needs around 10milli amps to be energized, the microcontroller‘s pin canprovide a maximum of 1-2milli amps current. For this reason, a driver such as a powertransistor is placed in between the microcontroller and the relay.The operation of this circuit is as follows:i. The input to the base of the transistor is applied from the microcontroller port pinP1.0.ii. The transistor will be switched on when the base to emitter voltage is greater than0.7V (cut-in voltage). Thus when the voltage applied to the pin P1.0 is high i.e.,P1.0=1 (>0.7V), the transistor will be switched on and thus the relay will be ON andthe load will be operated.iii. When the voltage at the pin P1.0 is low i.e., P1.0=0 (<0.7V) the transistor will be inoff state and the relay will be OFF. Thus the transistor acts like a current driver tooperate the relay accordingly.2.2.5 RelayA relay is an electrically operated switch. Current flowing through the coil of the relaycreates a magnetic field which attracts a lever and changes the switch contacts. The coilcurrent can be on or off so relays have two switch positions and they are double throw(changeover) switches.Relays allow one circuit to switch and second circuit which can be completely separatefrom the first. For example a low voltage battery circuit can use a relay to switch a 230VAC mains circuit. There is no electrical connection inside the relay between the twocircuits; the link is magnetic and mechanical.The coil of a relay passes a relatively large current, typically 30mA for a 12Vrelay, but itcan be as much as 100mA for relays designed to operate from lower voltages. Most ICs(chips) cannot provide this current and transistors usually used to amplify the small ICcurrent to the larger value required for the relay coil. Relays are usually SPDT (singlepole double throw) or DPDT (double pole double throw) but they can have many moresets of switch contacts, for example relays with 4 sets of changeover contacts are readily
  20. 20. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 20available. Relays used in our project have got a Coil rating of 12V, and Contact rating of10 Amps.2.2.7 Jammer blocksJammer block mainly consists of three parts, they arei. Power supply.ii. IF section.iii.RF section.2.2.8 Control switch setHere the control switch is used to set the timer of Jammer block and it is also used for toselect different jamming frequency i.e. GSM, CDMA, 3G. The Microcontroller scansthese switches continuously to detect and identify the jamming frequency and jammingduration.2.2.9 Reset circuitReset button is used to initialize the operation of microprocessor and resets input andoutput ports of microprocessor and program counter.
  21. 21. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 21CHAPTER 3OPERATION OF CELL PHONE JAMMERJamming devices overpower the cell phone by transmitting a signal on the same frequencyas the cell phone and at a high enough power that the two signals collide andcancel each other out. Cell phones are designed to add power if they experience low-levelinterference, so the jammer must recognize and match the power increase fromthe phone. Cell phones are full-duplex devices, which mean they use two separatefrequencies, one for talking and one for listening simultaneously . Some jammersblock only one of the frequencies used by cell phones, which has the effect ofblocking both. The phone is tricked into thinking there is no service becauseit can receive only one of the frequencies. Less complex devices block only one groupof frequencies, while sophisticated jammers can block several types of networks at once tohead off dual-mode or tri-mode phones that automatically switch amongdifferent network types to find an open signal. Some of the high-end devices block allfrequencies at once and others can be tuned to specific frequencies.To jam a cell phone, all you need is a device that broadcasts on the correct frequencies.Although different cellular systems process signals differently, all cell-phone networks useradio signals that can be interrupted. GSM, used in digital cellular and PCS-based systems,operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the1900-MHz (sometimes referred to as 1.9-GHz) band in the United States. Jammers canbroadcast on any frequency and are effective against AMPS, CDMA, TDMA, GSM, PCS,DCS, iDEN and Nextel systems. Old fashioned analog cell phones and todaysdigital devices are equally susceptible to jamming. Disrupting a cell phone is thesame as jamming any other type of radio communication. A cell phone works bycommunicating with its service network through a cell tower or base station.Cell towers divide a city into small areas, or cells. As a cell phone user drives downthe street, the signal is handed from tower to tower as shown in Figure 3.1.
  22. 22. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 22Figure 3.1 : Signal handed from tower to towerA jamming device transmits on the same radiofrequencies as the cell phone, disrupting thecommunication between the phone and the cell-phone base station in the town as shown inFigure 3.2. Its a called a denial-of-service attack. The jammer denies service of the radiospectrum to the cell-phone users within range of the jamming device. Older jammerssometimes were limited to working on phones using only analog or older digitalmobile phone standards. Newer models such as the double and triple band jammerscan block all widely used systems (AMPS, iDEN, GSM, etc.) and are even veryeffective against newer phones which hop to different frequencies and systemswhen interfered with. As the dominant network technology and frequencies usedfor mobile phones vary worldwide, some work only in specific regions such as Europe orNorth America.
  23. 23. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 23Figure 3.2 : Denial of service attackThe power of the jammers effect can vary widely based on factors such asproximity to towers, indoor and outdoor settings, presence of buildings and landscape,even temperature and humidity play a role. There are concerns that crudelydesigned jammers may disrupt the functioning of medical devices such aspacemakers. However, like cell phones, most of the devices in common useoperate at low enough power output (<1W) to avoid causing any problems.3.1 MOBILE JAMMING TECHNIQUES3.1.1 Type "A" Device: JAMMERSIn this device we overpower cell phones signal with a stronger signal, This typeof device comes equipped with several independent oscillators transmitting‗jamming signals‘ capable of blocking frequencies used by paging devices as wellas those used by cellular/PCS systems‘ control channels for call establishment. Whenactive in a designated area, such devices will (by means of RF interference) prevent
  24. 24. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 24all pagers and mobile phones located in that area from receiving andtransmitting calls. This type of device transmits only a jamming signal and hasvery poor frequency selectivity, which leads to interference with a largeramount of communication spectrum than it was originally intended to target. TechnologistJim Mahan said, ―There are two types. One is called brute force jamming,which just blocks everything. The problem is, it‘s like power-washing the airwavesand it bleeds over into the public broadcast area. The other puts out a small amount ofinterference, and you could potentially confine it within a single cell block. Youcould use lots of little pockets of small jamming to keep a facility under control.‖3.1.2 Type “B” Device: INTELLIGENT CELLULAR DISABLERSUnlike jammers type ―B‖ devices do not transmit an interfering signal on the controlchannels. The device, when located in a designated ‗quiet‘ area, functions as a ‗detector ‘.It has a unique identification number for communicating with the cellular base station.When a Type ―B‖ device detects the presence of a mobile phone in the quietroom; the ‗filtering‘ (i.e. The prevention of authorization of call establishment) is doneby the software at the base station.When the base station sends the signaling transmission to a target user , the device afterdetecting simultaneously the presence of that signal and the presence of thetarget user, signals the base station that the target user is in a ‗quiet‘ room;therefore, do not establish the communication. Messages can be routed to the user‘svoice- mail box, if the user subscribes to a voice-mail service. This process ofdetection and interruption of call establishment is done during the intervalnormally reserved for signaling and handshaking. For ‗emergency users‘, the intelligentdetector device makes provisions for designated users who have emergencystatus. These users‘ must pre-register their phone numbers with the service providers.When an incoming call arrives, the detector recognizes that number and the callare established for a specified maximum duration, say two minutes. The emergencyusers are also allowed to make outgoing calls. Similarly, the system is capable ofrecognizing and allowing all emergency calls routed to ―911‖.
  25. 25. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 25It should be noted that the Type ―B‖ detector device being an integral partof the cellular/PCS systems, would need to be provisioned by the cellular/PCSservice providers or provisioned by a third-party working cooperatively with fullsupport of the cellular/PCS service providers.3.1.3 Type “C” Device: INTELLIGENT BEACON DISABLERSUnlike jammers, Type ―C‖ devices do not transmit an interfering signal on the controlchannels. The device, when located in a designated ‗quiet‘ area, functions as a ‗beacon‘and any compatible terminal is instructed to disable its ringer or disable itsoperation, while within the coverage area of the beacon. Only terminals which have acompatible receiver would respond and this would typically be built on a separatetechnology from cellular/PCS, e.g., cordless wireless, paging, ISM, Bluetooth. On leavingthe coverage area of the beacon, the handset must re-enable its normal function.This technology does not cause interference and does not require any changesto existing PCS/cellular operators. The technology does require intelligent handsets with aseparate receiver for the beacon system from the cellular/PCS receiver. It willnot prevent normal operation for incompatible legacy terminals within a ―quiet‖coverage area, thus effective deployment will be problematic for man-years.While general uninformed users would lose functionality, pre-designated―emergency‖ users could be informed of a ―bypass terminal key sequence‖ to inhibitresponse to the beacon. Assuming the beacon system uses a technology with its ownlicense (or in the license exempt band), no change to the regulations are neededto deploy such a system. With this system, it would be extremely difficult to policemisuse of the ―bypass key sequence by users.3.1.4 Type “D” Device: DIRECTRECEIVE & TRANSMIT JAMMERSThis jammer behaves like a small, independent and portable base station,which can directly interact intelligently or unintelligently with the operation of the localmobile phone. The jammer is predominantly in receiving mode and willintelligently choose to interact and block the cell phone directly if it is within close
  26. 26. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 26proximity of the jammer. This selective jamming technique uses a discriminatingreceiver to target the jamming transmitter. The benefit of such targetingselectivity is much less electromagnetic pollution in terms of raw powertransmitted and frequency spectrum from the jammer , and therefore much lessdisruptive to passing traffic. The jam signal would only stay on as long as themobile continues to make a link with the base station, otherwise there would be nojamming transmission – the technique forces the link to break or unhook andthen it retreats to a passive receive mode again.This technique could be implemented without cooperation from PCS/cellular providers, butcould negatively impact PCS/cellular system operation. This technique has an addedadvantage over Type B in that no added overhead time or effort is spentnegotiating with the cellular network. As well as Type B, this device coulddiscriminate 911 calls and allow for breakthrough‖ during emergencies.3.1.5 Type “E” Device: EMI SHIELD - PASSIVE JAMMINGThis technique is using EMI suppression techniques to make a room into what iscalled a Faraday cage. Although labor intensive to construct, the Faraday cage essentiallyblocks, or greatly attenuates, virtually all electromagnetic radiation from entering orleaving the cage – or in this case a target room. With current advances in EMI shieldingtechniques and commercially available products one could conceivably implement thisinto the architecture of newly designed buildings for so-called ―quiet-conference‖rooms. Emergency calls would be blocked unless there was a way to receive and decodethe 91 1 transmissions, pass by coax outside the room and re-transmitted. This passiveconfiguration is currently legal in most worlds‘ countries for any commercial or residentiallocation in so far as DOC Industry Canada is concerned, however municipal or provincialbuilding code by-laws mayor may not allow this type of construction. Table 3.1 shows acomparison between the different jammer/disablers techniques.
  27. 27. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 27Table 3.1 : Comparison between jammer/disablers techniques3.2 MOBILE JAMMING REQUIREMENTSJamming objective is to inject an interference signal into the communications frequencyso that the actual signal is completely submerged by the interference. It is important tonotice that transmission can never be totally jammed - jamming hinders the reception atthe other end. The problem here for the jammer is that only transmitters can be foundusing direction finding and the location of the target must be a specific location, usuallywhere the jammer is located and this is because the jamming power is never infinite.Jamming is successful when the jamming signal denies the usability of thecommunications transmission. In digital communications, the usability is denied when theerror rate of the transmission cannot be compensated by error correction. Usually a
  28. 28. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 28successful jamming attack requires that the jammer power is roughly equal to signalpower at the receiver. The effects of jamming depend on the jamming-to-signal ratio(J/S), modulation scheme, channel coding and interleaving of the target system. GenerallyJamming-to-Signal ratio can be measured according to the following Equation.Pj= jammer power.Pt= transmitter power.Gjr= antenna gain from jammer to receiver.Grj= antenna gain from receiver to Jammer.Gtr= antenna gain from transmitter to receiver.Grt= antenna gain from receiver to transmitter.Br= communications receiver bandwidth.Bj= jamming transmitter bandwidth.Rtr= range between communications transmitter and receiver.Rjt= range between jammer and communications receiver.Lj= jammer signal loss (including polarization mismatch).Lr= communication signal loss.The above Equation indicates that the jammer Effective Radiated Power, which is theproduct of antenna gain and output power, should be high if jamming efficiency isrequired. On the other hand, in order to pr event jamming, the antenna gain toward thecommunication partner should be as high as possible while the gain towards the jammer
  29. 29. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 29should be as small as possible. As the equation shows, the antenna pattern, the relationbetween the azimuth and the gain, is a very important aspect in jamming.Also as we know from Microwave and shown in the equation distance has a stronginfluence on the signal loss. If the distance between jammer and receiver is doubled, thejammer has to quadruple its output in order for the jamming to have the same effect. Itmust also be noted here the jammer path loss is often different from the communicationspath loss; hence gives jammer an advantage over communication transmitters. In theGSM network, the Base Station Subsystem (BSS) takes care of the radio resources. Inaddition to Base Transceiver Station (BTS), the actual RF transceiver, BSS consists ofthree parts. These are the Base Station Controller (BSC), which is in charge of mobilitymanagement and signaling on the Air-interface between Mobile Station (MS), the BTS,and the Air-interface between BSS and Mobile Services Switching Center (MSC).UPLINK DOWNLINKGSM 900 890 – 950 MHz 935 – 960 MHzDCS 1800 1710 – 1785 MHz 1805 – 1880 MHz3G 1850 – 1910MHz 2110 – 2170MHzTable 3.2 : GSM, DCS and 3G frequency bandThe comparison between the frequency bands is as shown in Table 3.2.Frequency Hopping in GSM is intended for the reduction of fast fading caused bymovement of subscribers. The hopping sequence may use up to 64 different frequencies,which is a small number compared to military FH systems designed for avoidingjamming. Also, the speed of GSM hopping is approximately 200 hops /s; So GSMFrequency Hopping does not provide real protection against jamming attacks.Although FH doesn‘t help in protection against jamming, interleaving and forward errorcorrection scheme GSM Systems can protect GSM against pulsed jamming. For GSM it
  30. 30. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 30was shown that as the specified system SNR is 9 dB, a jammer min requires a 5 dB S/J inorder to successfully jam a GSM channel. The optimum GSM SNR is 12 dB, after thispoint the system starts to degrade.GSM system is capable to withstand abrupt cuts in Traffic Channel (TCH) connections.These cuts are normally caused by propagation losses due to obstacles such as bridges.Usually another cell could be used to hold communication when the original BTS hasdisconnected. The GSM architecture provides two solutions for this: first handover whenthe connection is still available, second call reestablishment when the original connectionis totally lost. Handover decisions are made based on transmission quality andreception level measurements carried out by the MS and the BTS. In jamming situationscall re-establishment is probably the procedure the network will take in order to re-connect the jammed TCH.It is obvious that downlink jamming (i.e. jamming the mobile station handset(receiver) iseasier than uplink, as the base station antenna is usually located far away from the MS ona tower or a high building. In the above table 3.2 we shown that the uplink and downlinkfrequency range of different network. This makes it efficient for the jammer to overpowerthe signal from BS. But the Random Access Channel (RACH) control channels of allBTSs in the area need to be jammed in order to cut off transmission. To cut an existingconnections, the jamming has to last at least until the call re-establishment timer at theMSC expires and the connection is released, which means that an existing call can be cutafter a few seconds of effective jamming.The GSM RACH random access scheme is very simple: when a request is not answered,the mobile station will repeat it after a random interval. The maximum number ofrepetitions and the time between them is broadcast regularly. After a MS has tried torequest service on RACH and has been rejected, it may try to request service fromanother cell. Therefore, the cells in the area should be jammed. In most cases, theefficiency of a cellular jamming is very difficult to determine, since it depends on manyfactors, which leaves the jammer confused.
  31. 31. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 31CHAPTER 4HARDWARE IMPLEMENTATION4.1 CIRCUIT DIAGRAMCircuit diagram involves rectifier, PIC microcontroller, LCD, relay and jammer. Thecircuit diagram of cell phone jammer is as shown in Figure 4.1.Figure 4.1 : Circuit diagram of Cell Phone Jammer
  32. 32. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 32The system basically consists ofi. Regulated power supply.ii. Microcontroller.iii. Relay.iv. LCD display.v. Cell phone jammer schematic.4.2 REGULATED POWER SUPPLY4.2.1 DESCRIPTIONA variable regulated power supply, also called a variable bench power supply, is onewhere you can continuously adjust the output voltage to your requirements. Varying theoutput of the power supply is the recommended way to test a project after having doublechecked parts placement against circuit drawings and the parts placement guide. This typeof regulation is ideal for having a simple variable bench power supply. Actually this isquite important because one of the first projects a hobbyist should undertake is theconstruction of a variable regulated power supply. While a dedicated supply is quitehandy e.g. 5V or 12V, its much handier to have a variable supply on hand, especially fortesting. Most digital logic circuits and processors need a 5 volt power supply. To usethese parts we need to build a regulated 5 volt source. Usually you start with anunregulated power supply ranging from 9 volts to 24 volts DC (A 12 volt power supply isincluded with the Beginner Kit and the Microcontroller Beginner Kit.). To make a 5 voltpower supply, we use a LM7805 voltage regulator IC shown in Figure 4.2.The LM7805 is simple to use. You simply connect the positive lead of your unregulatedDC power supply (anything from 9VDC to 24VDC) to the Input pin, connect the negativelead to the Common pin and then when you turn on the power, you get a 5volt supplyfrom the Output pin.
  33. 33. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 33Figure 4.2 : Regulated power supply ICCircuit features Brief description of operation: Gives out well regulated +5V output, outputcurrent capability of 100 mA. Circuit protection: Built-in overheating protection shuts down output whenregulator IC gets too hot Circuit complexity: Very simple and easy to build. Circuit performance: Very stable +5V output voltage, reliable operation. Availability of components: Easy to get, uses only very common basiccomponents. Design testing: Based on datasheet example circuit, we have used this circuitsuccessfully as part of many electronics projects. Applications: Part of electronics devices, small laboratory power supply. Power supply voltage: Unregulated DC 5V-18V power supply. Power supply current: Needed output current + 5 Ma. Component costs: Few dollars for the electronics components + the inputtransformer cost.
  34. 34. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 344.2.2 IC VOLTAGE REGULATORSVoltage regulators comprise a class of widely used ICs. Regulator IC units contain thecircuitry for reference source, comparator amplifier, control device, and overloadprotection all in a single IC. Although the internal construction of the IC is somewhatdifferent from that described for discrete voltage regulator circuits, the external operationis much the same. IC units provide regulation of either a fixed positive voltage, a fixednegative voltage, or an adjustable set voltage.A power supply can be built using a transformer connected to the ac supply line to stepthe ac voltage to desired amplitude, then rectifying that through an ac voltage, filteringwith a capacitor and RC filter, if desired, and finally regulating the dc voltage using an ICregulator. The regulators can be selected for operation with load currents from hundredsof mA to tens of amperes, corresponding to power ratings from mill watts to tens of watts.4.2.3 THREE – TERMINAL VOLTAGE REGULATORFigure 4.3 : Basic connection of a three – terminal voltage regulator IC to a loadFigure 4.3 shows the basic connection of a three - terminal voltage regulator IC to a load.The fixed voltage regulator has an unregulated dc input voltage, VIN, applied to one inputterminal, a regulated output dc voltage, VOUT, from a second terminal, with the thirdterminal connected to ground. While the input voltage may vary over some permissiblevoltage range, and the output load may vary over some acceptable range, the outputvoltage remains constant within specified voltage variation limits. The IC LM7805 takesa maximum voltage of +35 volts and gives an output of +5 volts.
  35. 35. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 354.2.4 BLOCK DIAGRAM OF POWER SUPPLYFigure 4.4 shows the block diagram of power supply. A 230V, 50Hz AC input signal isapplied to bridge rectifier circuit. After rectification, the output of the rectifier is filteredby using Low Pass Filter (LPF) which removes unwanted high frequency ripplecomponents, and then it is regulated to produce a constant DC output.Figure 4.4 : Block diagram of power supply4.3 MICROCONTROLLER (PIC16F877A)4.3.1 BRIEF HISTORY OF PIC16F877AThe original PIC was built to be used with General Instruments new 16-bit CPU, theCP1600. While generally a good CPU, the CP1600 had poor I/O performance, and the 8-bit PIC was developed in 1975 to improve performance of the overall system byoffloading I/O tasks from the CPU. The PIC used simple microcode stored in ROM toperform its tasks, and although the term was not used at the time, it shares some commonfeatures with RISC designs. In 1985, General Instrument spun off their microelectronicsdivision and the new ownership cancelled almost everything — which by this time wasmostly out-of-date. The PIC, however, was upgraded with internal EPROM to produce a
  36. 36. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 36programmable channel controller and today a huge variety of PICs are available withvarious on-board peripherals (serial communication modules, UARTs, motor controlkernels, etc.) and program memory from 256 words to 64k words and more (a "word" isone assembly language instruction, varying from 12, 14 or 16 bits depending on thespecific PIC micro family).PIC and PIC micro are registered trademarks of Microchip Technology. It is generallythought that PIC stands for Peripheral Interface Controller, although GeneralInstruments original acronym for the initial PIC1640 and PIC1650 devices was"Programmable Interface Controller". The acronym was quickly replaced with"Programmable Intelligent Computer". The Microchip 16C84 (PIC16x84), introducedin 1993, was the first Microchip CPU with on-chip EEPROM memory. This electricallyerasable memory made it cost less than CPUs that required quartz "erase window" for erasingEPROM.PIC is a family of architecture microcontrollers made by Microchip Technology, derivedfrom the PIC1650 originally developed by General Instruments MicroelectronicsDivision. The name PIC initially referred to "Peripheral Interface Controller". PICs arepopular with both industrial developers and hobbyists alike due to their low cost, wideavailability, large user base, extensive collection of application notes, availability of lowcost or free development tools, and serial programming (and re-programming with flashmemory) capability. Microchip announced on September 2011 the shipment of its tenbillionth PIC processor.4.3.2 FEATURES OF MICROCONTROLLER (PIC16F877A)The PIC16FXX series has more advanced and developed features when compared to itsprevious series. The important features of PIC16F877 series is given below.General Features High performance RISC CPU. ONLY 35 simple word instructions. All single cycle instructions except for program branches which are two Cycles.
  37. 37. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 37 Operating speed: clock input (200MHz), instruction cycle (200nS). Up to 368×8bit of RAM (data memory), 256×8 of EEPROM (data memory), and8k×14 of flash memory. Pin out compatible to PIC 16C74B, PIC 16C76, PIC 16C77. Eight level deep hardware stack. Interrupt capability (up to 14 sources). Different types of addressing modes (direct, Indirect, relative addressing modes). Power on Reset (POR). Power-Up Timer (PWRT) and oscillator start-up timer. Low power- high speed CMOS flash/EEPROM. Fully static design. Wide operating voltage range (2.0 – 5.56) volts. High sink/source current (25mA). Commercial, industrial and extended temperature ranges. Low power consumption (<0.6mA typical @3V-4MHz, 20µA typical @3V-32MHz and <1 A typical standby).Key Features Maximum operating frequency is 20MHz. Flash program memory (14 bit words), 8KB. Data memory (bytes) is 368. EEPROM data memory (bytes) is 256. 5 input/output ports. 3 timers. 2 CCP modules. 2 serial communication ports (MSSP, USART). PSP parallel communication port. 10bit A/D module (8 channels).
  38. 38. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 384.3.3 PIN CONFIGURATIONS of PIC16F877AINPUT/OUTPUT PORTSPIC16F877 has 5 basic input/output ports with its bit wide shown below Table 4.1. Theyare usually denoted by PORT A (RA), PORT B (RB), PORT C (RC), PORT D (RD), andPORT E (RE). These ports are used for input/ output interfacing. In this controller,―PORT A‖ is only 6 bits wide (RA-0 to RA-5), ‖PORT B‖,―PORT C‖,‖PORT D‖ areonly 8 bits wide (RB-0 to RB-7,RC-0 to RC-7,RD-0 to RD-7),‖PORT E‖ has only 3 bitwide (RE-0 to RE-2), All these ports are bi-directional.Table 4.1 : Input/output portsPORT-A RA-0 to RA-5 6 bit widePORT-B RB-0 to RB-7 8 bit widePORT-C RC-0 to RC-7 8 bit widePORT-D RD-0 to RD-7 8 bit widePORT-E RE-0 to RE-2 3 bit wide
  39. 39. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 39Figure: 4.5 : Pin configuration of PIC16F877AFigure 4.5 shows the pin configuration of PIC16F877A. The direction of the port iscontrolled by using TRIS(X) registers (TRIS A used to set the direction of PORT-A,TRIS B used to set the direction for PORT-B, etc.). Setting a TRIS(X) bit ‗1‘ will set thecorresponding PORT(X) bit as input. Clearing a TRIS(X) bit ‗0‘ will set thecorresponding PORT(X) bit as output.(If we want to set PORT A as an input, just setTRIS(A) bit to logical ‗1‘ and want to set PORT B as an output, just set the PORT B bitsto logical ‗0‘).i. Analog input port (AN0 TO AN7) : these ports are used for interfacing analoginputs. TX and RX: These are the USART transmission and reception ports. SCK: these pins are used for giving synchronous serial clock input.
  40. 40. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 40 SCL: these pins act as an output for both SPI and I2C modes. DT: these are synchronous data terminals. CK: synchronous clock input. SD0: SPI data output (SPI Mode). SD1: SPI Data input (SPI mode). SDA: data input/output in I2C Mode. CCP1 and CCP2: these are capture/compare/PWM modules. OSC1: oscillator input/external clock. OSC2: oscillator output/clock out. MCLR: master clear pin (Active low reset). Vpp: programming voltage input. THV: High voltage test mode controlling. Vref (+/-): reference voltage. SS: Slave select for the synchronous serial port. T0CK1: clock input to TIMER 0. T1OSO: Timer 1 oscillator output. T1OS1: Timer 1 oscillator input. T1CK1: clock input to Timer 1. PGD: Serial programming data. PGC: serial programming clock. PGM: Low Voltage Programming input. INT: external interrupt. RD: Read control for parallel slave port. CS: Select control for parallel slave. PSP0 to PSP7: Parallel slave port. VDD: positive supply for logic and input pins. VSS: Ground reference for logic and input/output pins.
  41. 41. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 414.4 RELAYA relay is an electrically operated switch. Current flowing through the coil of the relaycreates a magnetic field which attracts a lever and changes the switch contacts. The coilcurrent can be on or off so relays have two switch positions and they are double throw(changeover) switches.InductorFigure: 4.6 : Basic relay switch and relay framesBasic relay switch and relay frames are shown in above Figure 4.6. Relays allow onecircuit to switch a second circuit which can be completely separate from the first. Forexample a low voltage battery circuit can use a relay to switch a 230V AC mains circuit.There is no electrical connection inside the relay between the two circuits; the link ismagnetic and mechanical.The coil of a relay passes a relatively large current, typically 30mA for a 12V relay, but itcan be as much as 100mA for relays designed to operate from lower voltages. Most ICs(chips) cannot provide this current and a transistor is usually used to amplify the small ICcurrent to the larger value required for the relay coil. The maximum output current for thepopular 555 timer IC is 200mA so these devices can supply relay coils directly withoutamplification.Relays are usually SPDT or DPDT but they can have many more sets of switch contacts,for example relays with 4 sets of changeover contacts are readily available. For furtherinformation about switch contacts and the terms used to describe them please see the pageon switches. Most relays are designed for PCB mounting but you can solder wiresdirectly to the pins providing you take care to avoid melting the plastic case of the relay.The supplier‘s catalogue should show you the relays connections. The coil will beONCOMNC
  42. 42. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 42obvious and it may be connected either way round. Relay coils produce brief high voltagespikes ‗when they are switched off and this can destroy transistors and ICs in the circuit.To prevent damage you must connect a protection diode across the relay coil.The Figure 4.7 shows a working relay with its coil and switch contacts. You can see alever on the left being attracted by magnetism when the coil is switched-on. This levermoves the switch contacts. There is one set of contacts (SPDT) in the foreground andanother behind them, making the relay DPDT.Figure: 4.7 : Relay with its coil and switch contactsThe relays switch connections are usually labeled COM, NC and NO. COM = Common, always connect to this; it is the moving part of the switch. NC = Normally Closed, COM is connected to this when the relay coil is OFF. NO = Normally Open, COM is connected to this when the relay coil is ON. Connect to COM and NO if you want the switched circuit to be on when therelay coil is on. Connect to COM and NC if you want the switched circuit to be on when therelay coil is off.Advantages of relaysi. Relays can switch AC and DC, transistors can only switch DC.ii. Relays can switch high voltages, transistors cannot.iii.Relays are a better choice for switching large currents (> 5A).iv. Relays can switch many contacts at once.
  43. 43. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 43Disadvantages of relaysi. Relays are bulkier than transistors for switching small currents.ii. Relays cannot switch rapidly (except reed relays), transistors can switch manyiii.Times per second.iv. Relays use more power due to the current flowing through their coil.4.5 LCD DISPLAYLCD stands for Liquid Crystal Display. To display interactive messages we are usingLCD Module. We examine an intelligent LCD display of two lines, 16 characters per linethat is interfaced to the controllers. The protocol (handshaking) for the display is asshown. Whereas D0 to D7th bit is the Data lines, RS, RW and EN pins are the controlpins and remaining pins are +5V, -5V and GND to provide supply. Where RS is theRegister Select, RW is the Read Write and EN is the Enable pin.The display contains two internal byte-wide registers, one for commands (RS=0) and thesecond for characters to be displayed (RS=1). It also contains a user-programmed RAMarea (the character RAM) that can be programmed to generate any desired character thatcan be formed using a dot matrix..Figure 4.8 : 2x16 line alphanumeric LCD displayMost commonly used ALPHANUMERIC displays are 1x16 (Single Line & 16characters), or 2x16 (Double Line & 16 character per line). Figure 4.8 shows 2x16 linealphanumeric LCD display. The LCD requires 3 control lines (RS, R/W & EN) & 8 (or 4)data lines. The number on data lines depends on the mode of operation.
  44. 44. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 44Pin description of LCD:-Pin Symbol Function1 Vss Ground2 VddSupplyVoltage3 VoContrastSetting4 RSRegisterSelect5 R/WRead/WriteSelect6 EnChipEnable Signal7-14DB0-DB7Data Lines15 A/VeeGround forthe backlight16 KVcc forthe backlightFigure 4.9 : Pin description of LCD display
  45. 45. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 45Figure 4.9 shows the pin description of LCD display. When RS is low (0), the data is tobe treated as a command. When RS is high (1), the data being sent is considered as textdata which should be displayed on the screen. When R/W is low (0), the information onthe data bus is being written to the LCD.When R/W is high (1), the program is effectively reading from the LCD. Most of thetimes there is no need to read from the LCD so this line can directly be connected toGround thus saving one controller line.The ENABLE pin is used to latch the data present on the data pins. A HIGH - LOWsignal is required to latch the data. The LCD interprets and executes our command at theinstant the EN line is brought low. If you never bring EN low, your instruction will neverbe executed. Below Figure 4.10 shows how LCD interfaced to microcontroller.Figure 4.10 : LCD interface to microcontroller
  46. 46. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 464.6 CELL PHONE JAMMER SCHEMATICFigure 4.11 shows the schematic representation of cell phone jammer.Figure 4.11 : Cell phone jammer schematic
  47. 47. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 47The schematic consists of mainly1 Power supply.2 IF section.3 RF section.4.6.1 POWER SUPPLYThe power supply consists of the following main parts as shown in the Figure 4.12.Figure 4.12 : Power supply unitTransformer: Is used to transform the 220VAC to other levels of voltages.Rectification: This part is to convert the AC voltage to a DC one. We have two methodsfor rectification: Half wave-rectification: the output voltage appears only during positivecycles of the input signal. Full wave –rectification: a rectified output voltage occurs duringboth the positive and negative cycles of the input signal.The Filter: Used to eliminate the fluctuations in the output of the full wave rectifier―eliminate the noise‖ so that a constant DC voltage is produced. This filter is just a largecapacitor used to minimize the ripple in the output.Regulator: This is used to provide a desired DC-voltage.4.6.2 IF SECTIONThe block diagram of IF section is as shown in Figure 4.13. The function of the IF-sectionof the Mobile jammer is to generate the tuning signal for the VCO in the RF-Section, which will sweep the VCO through the desired range of frequencies.This tuning signal is generated by a triangular wave generator (1 10 KHz) along with noise
  48. 48. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 48generator, and then offset by proper amount so as to sweep the VCOoutput from the minimum desired frequency to a maximum.Figure 4.13 : Block diagram of IF sectionThe IF section consists of three main partsi. Triangle wave generator. (To tune the VCO in the RF section).ii. Noise generator (provides the output noise).iii. Signal mixer and DC offset circuits (to mix the triangle and the noise waves).Triangle wave generatorThe triangle wave generator consists of op-amp LM1458. Its block diagram and descriptionis as shown in Figure 4.14. The next op amp IC 1b is wired as an integrator.R5 is thefeedback resistor and C2 is the integrating capacitor. Non inverting input of IC 1b (pin6) istied to ground using resistor R7. The output of IC 1a which is a square wave is applied tothe inverting input of IC 1b (pin 5) through R4 which is the input resistance of IC 1b.Theoutput of IC 1b will be a triangular wave form, because integrating a square wave willresult in a triangular waveform. IC 2a forms another integrator, where R11 is its feedbackresistor and C3 is the integrating capacitor.R6 is the input resistance of IC 2a. Noninverting input of IC 2a (pin 3) is tied to ground using the 10K resistor R8. IC 2b forms aninverting amplifier where R9 is its input resistor and R10 the feedback resistor. With thevalues of R10 & R9, the gain of the inverting amplifier stage will be 27, (AV = -Rf/Rin).
  49. 49. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 49The triangular output waveform from the IC 1b is further integrated using IC 2a inverterusing IC 2b circuit diagram.Figure 4.14 : Simple function generator circuitNoise generatorTo achieve jamming a noise signal is mixed with the triangle wave signal to producethe tuning voltage for the VCO. The noise will help in masking the jamming transmission,making it look like random "noise‖ to an outside observer .Without the noise generator, thejamming signal is just a sweeping, unmodulated Continuous Wave RF carrier.The noise generator used in this design is based on the avalanche noise generatedby a Zener breakdown phenomenon. It is created when a PN junction isoperated in the reverse breakdown mode. The avalanche noise is very similar toshot noise, but much more intense and has a flat frequency spectrum (white).The magnitude of the noise is difficult to predict due to its dependence on the materials.Basically the noise generator circuit consists of a standard 6.8 volt zenerdiode with a small reverse current, a transistor buffer, and The NationalLM386 audio amplifier which acts as a natural band-pass filter and mall-signalamplifier.
  50. 50. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 50Signal mixer and DC offset circuitsFigure 4.15 : Op – amp summer circuitThe triangle wave and noise signals are mixed using OP-Amp configured as summershown in Figure 4.15, then a dc voltage is added to the resulted signal to obtain therequired tuning voltage using diode-clamper circuit that is shown in Figure 4.16. To gaingood clamping the RC time constant selected so that it‘s more than ten times the period ofthe input frequency, also a potentiometer was added to control the biasing voltage so as toget the desired tuning voltage.Figure 4.16 : Positive diode – clamper with bias
  51. 51. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 514.6.3 RF SECTIONThe block diagram of RF section is as shown in Figure 4.17.Figure 4.17 : Block diagram of RF sectionThe RF-section is the most important part of the mobile jammer it consists ofi. Voltage Controlled Oscillator (VCO).ii. RF Power amplifier.iii. Antenna.These components were selected according to the desired specification of thejammer such as the frequency range and the coverage range. It‘s important to note that allthe components used has 50 ohm input/output impedance, so 50 ohm microstrip was needed for matching between the components.Power requirementsTo successfully jam a particular region, we need to consider a very important parameterthe signal to noise ratio, referred to as the SNR. Every device working on radiocommunication principles can only tolerate noise in a signal up to a particular level. This
  52. 52. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 52is called the SNR handling capability of the device. Most cellular devices have a SNRhandling capability of around 12dB. A very good device might have a value of 9dB,although it is highly unlikely. To ensure jamming of these devices, we need to reduce theSNR of the carrier signal to below the 9dB level.For this, we consider the worst-case scenario from a jammers point of view. This wouldmean maximum transmitted power Smax from the tower, along with the lowest value ofthe SNR handling capability of a mobile device. So, mathematically,J = -24dBmSince SNRmin = S/JWhere J is the power of the jamming signal.So we need to have jamming signal strength of -24dBm at the mobile device‘s receptionto effectively jam it. However, our radiated signal will undergo some attenuation in beingtransmitted from the antenna of the jammer to the antenna of the mobile device. This pathloss can be calculated using the simple free space path loss approximation:Here f is the frequency in MHz, and D the distance traveled in kilometers. Using theGSM downlink center frequency (947.5MHz) and a jamming radius of 20m, we get thevalue of path loss to be 58dBm. This ideal path loss is for free space only, and the pathlosses in air will me much greater. This means that the jamming radius will be less thanthe 20m used to calculate this value. So, including the power lost in path loss, we need totransmit a signal with strength of:JT = 58 - 24 = 34dBmNow, the power output of our VCO is -3dBm, which needs to be amplified by 37dBm tomeet our requirements. For this, we used a two-stage amplification mechanism. The firststage is the MAR-4SM pre-amplifier, which provides a 8dBm power gain. This takes thepower level to 5dBm. To match the power to the input recommendation of the second
  53. 53. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 53amplification stage (the PF08103B), we need to attenuate this by 4dB, for which a pi-attenuator is used. Now the power level is 1dB, which is amplified by a gain of 33dB bythe PF08103B to an output power level of 34dBm.Voltage controlled oscillatorThe VCO is responsible for generating the RF signal which will over power the mobiledownlink signal. The selection of the VCO was influenced by two main factors, thefrequency of the GSM system, which will be jammed and the availability of the chip. Forthe first factor which implies that the VCO should cover the frequencies from 935 MHzto 960 MHz, The MAX2623 VCO from MAXIM IC was found to be a good choice, andfortunately the second factor was met sequentially since MAXIM IC was willing to sendtwo of the MAX2623 for free. The pin diagram of MAXIM is as shown in Figure 4.18.Figure 4.18 : Pin diagram of MAXIMThe MAX2623 VCO is implemented as an LS oscillator configuration, integratingall tank circuit of the tank circuit on-chip, this makes the VCO extremely easy-to use ,and the tuning input is internally connected to the varactor as shown in Figure 4.16 .Thetypical output power is -3dBm, and the output was best swept over the desired rangewhen the input tuning voltage was around 120 KHz.
  54. 54. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 54Figure 4.19 : MAXIM 2623 Pin connectionFigure 4.19 shows voltage controlled osillator MAXIM 2623 pin connections.About VCO:i. Fully Monolithic.ii. Guaranteed Performance.iii.On-Chip 50Ω Output Match.iv. 885MHz to 950MHz (MAX2623).v. +2.7V to +3.3V Single-Supply Operation.vi. Low Current Shutdown Mode.vii. Smaller than Modules (8-pin µMAX package).Pin description of VCO:1) NC- No Connection. Not internally connected.2) TUNE- Oscillator Frequency Tuning Voltage Input. High-impedance input with avoltage input range of 0.4V (low frequency) to 2.4V (high frequency) adjustment.
  55. 55. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 553) GND- Ground Connection for Oscillator and Biasing requires a low-inductanceconnection to the circuit board ground plane.4) SHDN- Shutdown Logic Input. A high-impedance input logic level low disables thedevice and reduces supply current to 0.1μA. A logic level high enables the device.5) VCC- Output Buffer DC Supply Voltage Connection, bypass with a 220pF capacitor toGND for best high frequency performance.6) VCC- Bias and Oscillator DC Supply Voltage Connection. Bypass with a 220pFcapacitor to GND for low noise and low spurious content performance from the oscillator.7) GND-Ground Connection for Output Buffer. Requires a low-inductance connection tothe circuit board ground plane.RF Power amplifierTo achieve the desired output power a gain stage was needed, about searching for asuitable power amplifier it is cheaper to use power amplifier from an old Mobile phones.The PF08103b Hitachi power amplifier module from Nokia mobile phone is sufficient toamplify an input signal in the range 800MHz to 1 GHz by 34 db. But in the data sheetinput should be 1dBm.To meet this requirement we use another power amplifier stageafter VCO and before Hitachi power amplifier .For this stage we use MAR-4SM poweramplifier, so the output at this stage is around 5dBm.A typical biasing configuration forMAR-4SM is shown in the Figure 4.20.Figure 4.20 : Typical biasing configuration for the MAR – 4SM
  56. 56. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 56Now the power before the Hitachi RF power amplifier is 5dBm and since 1dBm isrequired; so here we used 4dBm T-Network attenuator is as shown in the Figure 4.21.Figure 4.21 : T- Network attenuatorFor a 4-dB attenuation and symmetric Network S12=S21=0.631 And for 50 ohmscharacteristic impedance we found the values of the resistor using the followingequations.Where X= (R2+50))/R3.AntennaThe most important part of any transmitter is the antenna. So a suitable antenna should beselected .The antenna used in the project is λ/4 wave monopole antenna and it has 50Ohm impedance so that the antenna is matched to the transmission system .Also thisantenna has low VSWR less than 1.7, and a bandwidth of 150MHz around 916MHzcenter frequency which cover the mobile jammer frequency range .The antenna gain is2dBi. Figure 4.22 shows the monopole antenna.
  57. 57. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 57Figure 4.22 : Monopole antennaThe patterns of antenna are as shown in Figure 4.23.a) Monopole principle E – Plane patternb) Monopole principle H – Plane patternFigure 4.23 : Antenna patterns
  58. 58. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 58CHAPTER 5SOFTWARE IMPLEMENTATION5.1 FLOW CHARTYesNoYesNoBEGINAInitialize LCD,Clear LCDOutput string on LCD(Select NetworkDCS CDMA 3G)Issw0 =11Input from either ofthe switchessw0, sw1, sw2, sw3reset swSelected network―DCS‖IsReset sw=1AB CD
  59. 59. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 59NoYesYesNOYesNoYesCA BIssw1 =1Selected network―CDMA‖IsReset sw=1Issw2 =1Selected network―3G‖IsReset sw=1NoYesYesIssw3 =1Selected AllnetworkIsReset sw=1DNoNo2
  60. 60. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 602Wait for500msOutput string on LCD(Set on time)1IsReset sw=1Place cursor ofLCD to next rowPrint the number(time) on LCDPrint string ―mins‖on LCD1IsReset sw=1Input fromsw0 or sw1YesNoYesNoE
  61. 61. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 61IsSw0=1time=time+1EYesNoIsSw1=1time=time-1YesNoIs resetSw=1 13YesNo
  62. 62. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 623Is selectednetwork isDCSPrint string(DCS networkis on for)Print timeYesNoPrint string(CDMA networkis on for)Print timeNoIs selectednetwork isCDMAYesPrint string(3G network ison for)Print timeIs selectednetwork is3GF HGYesNo
  63. 63. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 63Print string (Allnetwork is onfor)Print timeIs Allnetwork isselectedF HGNoYesIsReset sw=1 1NoYesIsSw2=1Yes Run jammer for selectednetwork and time durationNoResetSw=1whilerunningAbort jammerEndYesNo11
  64. 64. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 645.2 SOURCE CODE#define PIC//Defines for microcontroller#define P16F877a//LCDDisplay(0): //Macro function declarationsvoid LCDDisplay0_RawSend(UINT8 in, UINT8 mask);void LCDDisplay0_Start();void LCDDisplay0_Clear();void LCDDisplay0_PrintASCII(UINT8 Character);void LCDDisplay0_Command(UINT8 in);void LCDDisplay0_Cursor(UINT8 x, UINT8 y);void LCDDisplay0_PrintNumber(SINT16 Number);void LCDDisplay0_PrintString(STRING String, UINT8 MSZ_String);void LCDDisplay0_ScrollDisplay(UINT8 Direction, UINT8 Num_Positions);void LCDDisplay0_ClearLine(UINT8 Line);void LCDDisplay0_RAM_Write(UINT8 nIdx, UINT8 d0, UINT8 d1, UINT8 d2, UINT8d3, UINT8 d4, UINT8 d5, UINT8 d6, UINT8 d7);//LCDDisplay(0): //Macro implementationsvoid LCDDisplay0_RawSend(UINT8 in, UINT8 mask){UINT8 pt;CAL_Bit_Low(LCD_5__PORT0, LCD_5__BIT0);CAL_Bit_Low(LCD_5__PORT1, LCD_5__BIT1);CAL_Bit_Low(LCD_5__PORT2, LCD_5__BIT2);CAL_Bit_Low(LCD_5__PORT3, LCD_5__BIT3);CAL_Bit_Low(LCD_5__PORT4, LCD_5__RS);CAL_Bit_Low(LCD_5__PORT5, LCD_5__E);pt = ((in >> 4) & 0x0f);if (pt & 0x01)CAL_Bit_High(LCD_5__PORT0, LCD_5__BIT0);if (pt & 0x02)CAL_Bit_High(LCD_5__PORT1, LCD_5__BIT1);if (pt & 0x04)CAL_Bit_High(LCD_5__PORT2, LCD_5__BIT2);if (pt & 0x08)CAL_Bit_High(LCD_5__PORT3, LCD_5__BIT3);if (mask)CAL_Bit_High(LCD_5__PORT4, LCD_5__RS);LCD_5__DELAY;
  65. 65. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 65CAL_Bit_High (LCD_5__PORT5, LCD_5__E);LCD_5__DELAY;CAL_Bit_Low (LCD_5__PORT5, LCD_5__E);pt = (in & 0x0f);LCD_5__DELAY;CAL_Bit_Low(LCD_5__PORT0, LCD_5__BIT0);CAL_Bit_Low(LCD_5__PORT1, LCD_5__BIT1);CAL_Bit_Low(LCD_5__PORT2, LCD_5__BIT2);CAL_Bit_Low(LCD_5__PORT3, LCD_5__BIT3);CAL_Bit_Low(LCD_5__PORT4, LCD_5__RS);CAL_Bit_Low(LCD_5__PORT5, LCD_5__E);if (pt & 0x01)CAL_Bit_High(LCD_5__PORT0, LCD_5__BIT0);if (pt & 0x02)CAL_Bit_High(LCD_5__PORT1, LCD_5__BIT1);if (pt & 0x04)CAL_Bit_High(LCD_5__PORT2, LCD_5__BIT2);if (pt & 0x08)CAL_Bit_High(LCD_5__PORT3, LCD_5__BIT3);if (mask)CAL_Bit_High(LCD_5__PORT4, LCD_5__RS);LCD_5__DELAY;CAL_Bit_High (LCD_5__PORT5, LCD_5__E);LCD_5__DELAY;CAL_Bit_Low (LCD_5__PORT5, LCD_5__E);LCD_5__DELAY;}void LCDDisplay0_Clear(){LCDDisplay0_RawSend(0x01, 0);Wdt_Delay_Ms(2);LCDDisplay0_RawSend(0x02, 0);Wdt_Delay_Ms(2);}void LCDDisplay0_PrintASCII(UINT8 Character){LCDDisplay0_RawSend(Character, 0x10);}
  66. 66. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 66void LCDDisplay0_Command(UINT8 in){LCDDisplay0_RawSend(in, 0);Wdt_Delay_Ms(2);}void LCDDisplay0_Cursor(UINT8 x, UINT8 y){#if (LCD_5__ROWCNT == 1)y=0x80;#endif#if (LCD_5__ROWCNT == 2)if (y==0)y=0x80;elsey=0xc0;#endif#if (LCD_5__ROWCNT == 4)if (y==0)y=0x80;else if (y==1)y=0xc0;#if (LCD_5__COLCNT == 16)else if (y==2)y=0x90;elsey=0xd0;#endif#if (LCD_5__COLCNT == 20)else if (y==2)y=0x94;elsey=0xd4;#endif#endifLCDDisplay0_RawSend(y+x, 0);Wdt_Delay_Ms(2);
  67. 67. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 67}void LCDDisplay0_PrintNumber(SINT16 Number){SINT16 tmp_int;UINT8 tmp_byte;if (Number < 0){LCDDisplay0_RawSend(-, 0x10);Number = 0 - Number;}tmp_int = Number;if (Number >= 10000){tmp_byte = tmp_int / 10000;LCDDisplay0_RawSend(0 + tmp_byte, 0x10);while (tmp_byte > 0){tmp_int = tmp_int - 10000;tmp_byte--;}}if (Number >= 1000){tmp_byte = tmp_int / 1000;LCDDisplay0_RawSend(0 + tmp_byte, 0x10);while (tmp_byte > 0){tmp_int = tmp_int - 1000;tmp_byte--;}}if (Number >= 100){tmp_byte = tmp_int / 100;LCDDisplay0_RawSend(0 + tmp_byte, 0x10);while (tmp_byte > 0){tmp_int = tmp_int - 100;tmp_byte--;
  68. 68. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 68}}if (Number >= 10){tmp_byte = tmp_int / 10;LCDDisplay0_RawSend(0 + tmp_byte, 0x10);while (tmp_byte > 0){tmp_int = tmp_int - 10;tmp_byte--;}}LCDDisplay0_RawSend(0 + tmp_int, 0x10);}void LCDDisplay0_PrintString(STRING String, UINT8 MSZ_String){UINT8 idx = 0;for (idx=0; idx<MSZ_String; idx++){if (String[idx] == 0){break;}LCDDisplay0_RawSend(String[idx], 0x10);}}void LCDDisplay0_ScrollDisplay(UINT8 Direction, UINT8 Num_Positions){UINT8 cmd = 0;UINT8 count;//Choose the directionswitch (Direction)
  69. 69. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 69{case 0:case l:case L:cmd = 0x18;break;case 1:case r:case R:cmd = 0x1C;break;default:break;}//If direction accepted then scroll the specified amountif (cmd){for (count = 0; count < Num_Positions; count++)LCDDisplay0_Command(cmd);}}void LCDDisplay0_ClearLine(UINT8 Line){UINT8 count;UINT8 rowcount;//Define number of columns per line#if (LCD_5__ROWCNT == 1)rowcount=80;#endif#if (LCD_5__ROWCNT == 2)rowcount=40;#endif#if (LCD_5__ROWCNT == 4)#if (LCD_5__COLCNT == 16)rowcount=16;#endif
  70. 70. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 70#if (LCD_5__COLCNT == 20)rowcount=20;#endif#endif//Start at beginning of the lineLCDDisplay0_Cursor (0, Line);//Send out spaces to clear linefor (count = 0; count < rowcount; count++)LCDDisplay0_RawSend( , 0x10);// Move back to the beginning of the line.LCDDisplay0_Cursor (0, Line);}void LCDDisplay0_RAM_Write (UINT8 nIdx, UINT8 d0, UINT8 d1, UINT8 d2, UINT8d3, UINT8 d4, UINT8 d5, UINT8 d6, UINT8 d7){//set CGRAM addressLCDDisplay0_RawSend(64 + (nIdx << 3), 0);delay_ms(2);//write CGRAM dataLCDDisplay0_RawSend (d0, 0x10);LCDDisplay0_RawSend (d1, 0x10);LCDDisplay0_RawSend (d2, 0x10);LCDDisplay0_RawSend (d3, 0x10);LCDDisplay0_RawSend (d4, 0x10);LCDDisplay0_RawSend (d5, 0x10);LCDDisplay0_RawSend (d6, 0x10);LCDDisplay0_RawSend (d7, 0x10);//Clear the displayLCDDisplay0_RawSend(0x01, 0);delay_ms(2);LCDDisplay0_RawSend(0x02, 0);delay_ms(2);}void time(){//Delay
  71. 71. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 71//Delay: 500 msdelay_ms(255);delay_ms(245);//Loop//Loop: While 1while (1){//Call Component Macro//Call Component Macro: Clear ()LCDDisplay0_Clear ();//Call Component Macro//Call Component Macro: PrintString ("Set On Time")LCDDisplay0_PrintString ("Set On Time", 11);//Call Component Macro//Call Component Macro: Cursor (0, 1)LCDDisplay0_Cursor (0, 1);//Call Component Macro//Call Component Macro: PrintNumber (time)LCDDisplay0_PrintNumber (TIME);//Call Component Macro//Call Component Macro: PrintString(" mins")LCDDisplay0_PrintString(" mins", 5);//Input//Input: B0 -> sw1trisb = trisb | 0x01;SW1 = ((portb & 0x01) == 0x01);//Decision//Decision: sw1 = 0?if (SW1 == 0){//Calculation//Calculation:// time = time + 1TIME = TIME + 1;// } else{
  72. 72. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 72}//Input//Input: B1 -> sw2trisb = trisb | 0x02;SW2 = ((portb & 0x02) == 0x02);//Decision//Decision: sw2 = 0?if (SW2 == 0){//Calculation//Calculation:// time = time - 1TIME = TIME - 1;// } else{}//Input//Input: B2 -> sw3trisb = trisb | 0x04;SW3 = ((portb & 0x04) == 0x04);//Decision//Decision: sw3 = 0?if (SW3 == 0){//Call Macro//Call Macro: start()start();//Goto Connection Point//Goto Connection Point: [A]: Agoto time_A;// } else{}//Input//Input: B3 -> sw4
  73. 73. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 73trisb = trisb | 0x08;SW4 = ((portb & 0x08) == 0x08);//Decision//Decision: sw4 = 0?if (SW4 == 0){//Goto Connection Point//Goto Connection Point: [A]: Agoto time_A;// } else{}//Delay//Delay: 300 msdelay_ms(255);delay_ms(45);}//Connection Point//Connection Point: [A]: Atime_A;}void start(){//Switch//Switch: network?switch (NETWORK){case 1:{//Call Component Macro//Call Component Macro: Clear()LCDDisplay0_Clear();//Call Component Macro//Call Component Macro: PrintString("DCS Network is ")LCDDisplay0_PrintString("DCS Network is ", 15);
  74. 74. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 74//Call Component Macro//Call Component Macro: Cursor(0, 1)LCDDisplay0_Cursor(0, 1);//Call Component Macro//Call Component Macro: PrintString("on for")LCDDisplay0_PrintString("on for", 6);//Call Component Macro//Call Component Macro: PrintNumber(time)LCDDisplay0_PrintNumber(TIME);//Call Component Macro//Call Component Macro: PrintString("mins")LCDDisplay0_PrintString("mins", 4);break;}case 2:{//Call Component Macro//Call Component Macro: Clear()LCDDisplay0_Clear();//Call Component Macro//Call Component Macro: Print String("CDMA Network is ")LCDDisplay0_PrintString("CDMA Network is ", 16);//Call Component Macro//Call Component Macro: Cursor(0, 1)LCDDisplay0_Cursor(0, 1);//Call Component Macro//Call Component Macro: Print String("on for")LCDDisplay0_PrintString("on for", 6);//Call Component Macro//Call Component Macro: Print Number(time)LCDDisplay0_PrintNumber(TIME);//Call Component Macro//Call Component Macro: Print String("mins")LCDDisplay0_PrintString("mins", 4);
  75. 75. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 75break;}case 3:{//Call Component Macro//Call Component Macro: Clear()LCDDisplay0_Clear();//Call Component Macro//Call Component Macro: PrintString("GSM Network is ")LCDDisplay0_PrintString("GSM Network is ", 15);//Call Component Macro//Call Component Macro: Cursor(0, 1)LCDDisplay0_Cursor(0, 1);//Call Component Macro//Call Component Macro: PrintString("on for")LCDDisplay0_PrintString("on for", 6);//Call Component Macro//Call Component Macro: PrintNumber(time)LCDDisplay0_PrintNumber(TIME);//Call Component Macro//Call Component Macro: PrintString("mins")LCDDisplay0_PrintString("mins", 4);break;}case 4:{//Call Component Macro//Call Component Macro: Clear()LCDDisplay0_Clear();//Call Component Macro//Call Component Macro: PrintString("All Network are")LCDDisplay0_PrintString("All Network are", 15);//Call Component Macro//Call Component Macro: Cursor(0, 1)LCDDisplay0_Cursor(0, 1);
  76. 76. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 76//Call Component Macro//Call Component Macro: PrintString("on for")LCDDisplay0_PrintString("on for", 6);//Call Component Macro//Call Component Macro: PrintNumber(time)LCDDisplay0_PrintNumber(TIME);//Call Component Macro//Call Component Macro: PrintString("mins")LCDDisplay0_PrintString("mins", 4);break;}// default:}//Output//Output: 1 -> A0trisa = trisa & 0xFE;if ((1))porta = (porta & 0xFE) | 0x01;elseporta = porta & 0xFE;//Calculation//Calculation:// delay = time * 60DELAY = TIME * 60;//Loop//Loop: While delay = 0while (!(DELAY == 0)){//Calculation//Calculation:// delay = delay - 1DELAY = DELAY - 1;//Delay//Delay: 1 sdelay_s(1);
  77. 77. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 77}//Output//Output: 0 -> A0trisa = trisa & 0xFE;if ((0))porta = (porta & 0xFE) | 0x01;elseporta = porta & 0xFE;}void main(){//Initializationadcon1 = 0x07;//Interrupt initialization codeoption_reg = 0xC0;//Output//Output: 0 -> A0trisa = trisa & 0xFE;if ((0))porta = (porta & 0xFE) | 0x01;elseporta = porta & 0xFE;//Call Component Macro//Call Component Macro: Start()LCDDisplay0_Start();//Loop//Loop: While 1while (1){//Call Component Macro//Call Component Macro: Clear()LCDDisplay0_Clear();//Call Component Macro//Call Component Macro: PrintString("Select Network")LCDDisplay0_PrintString("Select Network", 14);//Call Component Macro//Call Component Macro: Cursor(0, 1)
  78. 78. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 78LCDDisplay0_Cursor(0, 1);//Call Component Macro//Call Component Macro: PrintString("DCS CDMA 3G")LCDDisplay0_PrintString("DCS CDMA 3G", 15);//Input//Input: B0 -> sw1trisb = trisb | 0x01;SW1 = ((portb & 0x01) == 0x01);//Decision//Decision: sw1 = 0?if (SW1 == 0){//Calculation//Calculation:// network = 1NETWORK = 1;//Call Macro//Call Macro: time()time();// } else {}//Input//Input: B1 -> sw2trisb = trisb | 0x02;SW2 = ((portb & 0x02) == 0x02);//Decision//Decision: sw2 = 0?if (SW2 == 0){//Calculation//Calculation:// network = 2NETWORK = 2;//Call Macro//Call Macro: time()time();// } else
  79. 79. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 79{}//Input//Input: B2 -> sw3trisb = trisb | 0x04;SW3 = ((portb & 0x04) == 0x04);//Decision//Decision: sw3 = 0?if (SW3 == 0){//Calculation//Calculation:// network = 3NETWORK = 3;//Call Macro//Call Macro: time()time();// } else{}//Input//Input: B3 -> sw4trisb = trisb | 0x08;SW4 = ((portb & 0x08) == 0x08);//Decision//Decision: sw4 = 0?if (SW4 == 0){//Calculation//Calculation:// network = 4NETWORK = 4;//Call Macro//Call Macro: time()time();// } else{
  80. 80. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 80}//Delay//Delay: 300 msdelay_ms(255);delay_ms(45);}mainendloop: goto mainendloop;}void INTERRUPT_MACRO(void){}
  81. 81. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 81CHAPTER 6TESTING AND RESULTSTestingTo test the project, it has to be set to specific mode of operation, i.e. we have to select thetoggle switch according to our specification. The toggle switch has been shown in theFigure 6.1. It has three toggle switches, to run the jammer toggle switches are set tospecific operation mode:First toggle switch is used to charge the battery (when it is in the up side) and run thejammer (when it is in the down side).Second toggle switch is used to run the jammer with battery (when it is in the up side)and run the jammer with main power supply (when it is in the down side).Third toggle switch is used to turn on and off the control from PIC, but jammer runscontinuously.Figure 6.1 : Control toggle switches
  82. 82. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 82After the selection of toggle switch, next we have to select which network has to beblocked, so to select network kit consist of control switches. First switch selects the DCS(Digital Cellular System) network, second switch selects the CDMA network, and thirdswitch selects the 3G network and finally fourth switch selects all the networks.After selection of which network has to be blocked, next step is to set the time duration toblock the selected network. Time duration is set by the switch one and switch two byincrementing and decrementing the timer respectively.If time duration is selected, jammer is run to selected time duration and selected network,when we press the third switch .These are all the steps involved to run the jammer step bystep respectively are as shown in Figures 6.2, 6.3, 6.4 and 6.5.Figure 6.2 : Control switch to select networkFigure 6.3 : Control switch to set time duration
  83. 83. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 83Figure 6.4 : Control switch to run the jammerFigure 6.5 : Jammer running stage on LCD display
  84. 84. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 84ResultsAs we tested our jamming device, the result was a successful one. The device was able tojam the cell phones. Here we considered the worst case of having the cell phone close tothe base station where the effective jamming range was around 3-4 meters. It is expectedthat as the distance between the cell phone and the base station increases, the effectivejamming distance will also increase. This is due to the fact that the amount of powerreaching the cell phone from the base station decreases as the cell phone moves fartherfrom the base station. If jammer placed where the region covered by more towers anddistance between the cell phone and the base station is less, then blocking range will beless. The Figures 6.6 and 6.7 shows the results, it can be clearly seen that the signal is"ON" when the jammer is "OFF", while the signal disappears when the jammer is "ON"respectively.Figure 6.6 : Signal ON jammer OFF
  85. 85. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 85Figure 6.7 : Jammer ON signal OFF
  86. 86. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 86CHAPTER 7ADVANTAGES AND DISADVANTAGESAdvantagesi. We can provide security to V.I.P‘s from the anti-social elements.ii. By using cell phone jammers we can maintain law and order for maintainingpeace.iii. By cell phone jammers we can‘t disturb other people in the public places likerestaurants, shopping places.iv. It is very necessary to use cell phone jammers in naxal feared places. Thishelps the authorities to work their duty softly.v. By using cell phone jammers in the vehicles, we can overcome accidents problemwhich is very helpful to the people.vi. Works for both GSM and CDMA networks.vii. No loss of data due to backup battery.Disadvantagesi. Cost oriented.ii. Requires special hardware.iii. People feel inconvenience.iv. V.I.P.‘s may lose some important calls.
  87. 87. Cell phone jammer with prescheduled time durationDept. of ECE, GECH. 2013 Page 87CHAPTER 7APPLICATIONS Gas stations, the air entrainment station, the fuel depot and the flammableexplosive chemical warehouse, the refinery, the petrified factory and so onneed safely to protect place: May avoid changing suddenly the detonation whichthe signal radiative generation static electricity spark but causes, the fire. Posts theprohibition to dial the handset sign, does not have the initiative, this kind ofaccident all has the appearance in national many gas stations, in order to safeguardthese important situations the security to be supposed to take the precautionarymeasure. Governments, enterprises each kind of conference room: May avoid thehandset ting disturbs and answers when the telephone breaking the leader to speakbut interrupts its person to hold a meeting. Armies, public security departments important conference rooms: Might avoidthe attending personnel divulging the military and the government using the handsetis secret, at present the new spy science and technology, already used the handsetinterception, the monitor environment sound, therefore to important conferenceplace, it is necessary to take effective also of security the initiative. Hospitals: Might avoid the goon machine-hour but causing doctor to the hospitalprecision instrument equipment disturbance to misdiagnose, has delayed the rescuepatient, as well as was surgery doctor to answer the handset telephone disturbanceattention, underwent the surgery to doctor to the patient to be extremelydisadvantageous. Courts: May avoid the handset ting the disturbance, maintains the court conferencesite the dignity and the sacredness. Libraries, New Bookstore: May avoid the handset ting and answer the telephonethe noise, builds to study the study peaceful environment.

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