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A Mini Project Report on CELLPHONE DETECTOR Submitted to BHARATI VIDYAPEETH COLLEGE OF ENGINEERING,NAVI MUMBAI DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING By PRADNYA KHANDGE AMIT NIMSE AJINKYARAJ NAYAK Under the Esteemed guidance of Prof. Amina Qazi Department of ET

Cell Phone Detector

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Project report on cellphone detector

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A Mini Project Report onCELLPHONE DETECTORSubmitted toBHARATI VIDYAPEETH COLLEGE OF ENGINEERING,NAVI MUMBAIDEPARTMENT OF

Electronics and Communication Engineering

By

PRADNYA KHANDGEAMIT NIMSEAJINKYARAJ NAYAK

Under the Esteemed guidance ofProf. Amina QaziDepartment of ET

BHARATI VIDYAPEETH COLLEGE OF ENGINEERING

Department of Electronics and Communication Engineering

CERTIFICATE

This is to certify that the mini project entitled CELLPHONE DETECTOR is submitted byPRADNYA KHANDGEAMIT NIMSEAJINKYARAJ NAYAK

in partial fulfillment of the requirement for the Third Year of the degree Bachelor of Engineering in Department of Electronics and Communication Engineering from Bharati Vidyapeeth College Of Engineering, Navi Mumbai for the academic year 2014-2015.

Prof. Amina Qazi Prof. KharadeDepartment, ET Head of the Department, ET(Internal Guide)

Date:External Examiner

Contents

1. Abstract 22. Basic Block Diagram and Description 33. Detailed Circuit Diagram and Working54. Mathematical Analysis of the Circuit75. Making of PCB Layout and Schematic86. Project Implementation107. Testing118. Result129. Appendix13

Abstract

This handy, pocket-size mobile transmission detector or sniffer can sense the presence of an activated mobile cell phone from a distance of one and-a-half meters. So it can be used to prevent use of mobile phones in examination halls, confidential rooms, etc. It is also useful for detecting the use of mobile phone for Spying and unauthorized video transmission. The circuit can detect the incoming and outgoing calls, SMS and video transmission even if the mobile phone is kept in the silent mode. The moment the Bug detects RF transmission signal from an activated mobile phone, it starts sounding a beep alarm and the LED blinks. The alarm continues until the Signal Transmission Ceases

Basic Block Diagram

BLOCK DIAGRAM-

Mobile PhoneMobile Tower

Buzzer LEDPulse GeneratorAmplifierAntenna

Description: Mobile tower transmits the high frequency signal to the cell phone for communication. The antenna captures the high frequency signal transmitted by mobile tower to the mobile phone. The amplifier selects the proper frequency, which is often used for cell phone communication and sends the signal to the pulse generator. The pulse generator generates the signal pulses in respect with incoming signal. Pulses generated by pulse generator then given to the LED and Buzzer for proper indication of Cell phone signals.

Circuit Diagram

Working:

Here the circuit uses a 0.22F disk capacitor (C3) to capture the RF signals from the mobile phone. The lead length of the capacitor is fixed as 18 mm with a spacing of 8 mm between the leads to get the desired frequency. The disk capacitor along with the leads acts as a small gigahertz loop antenna to collect the RF signals from the mobile phone. Op-amp IC CA3130 (IC1) is used in the circuit as a current-to-voltage converter with capacitor C3 connected between its inverting and non-inverting inputs. It is a CMOS version using gate-protected p-channel MOSFET transistors in the input to provide very high input impedance, very low input current and very high speed of performance.The output CMOS transistor is capable of swinging the output voltage to within 10 mV of either supply voltage terminal. Capacitor C3 in conjunction with the lead inductance acts as a transmission line that intercepts the signals from the mobile phone. This capacitor creates a field, stores energy and transfers the stored energy in the form of minute current to the inputs of IC1.This will upset the balanced input of IC1 and convert the current into the corresponding output voltage.Capacitor C4 along with high-value resistor R1 keeps the non-inverting input stable for easy swing of the output to high state. Resistor R2 provides the discharge path for capacitor C4. Feedback resistor R3 makes the inverting input high when the output becomes high. Capacitor C5 (47pF) is connected across strobe (pin 8) and null inputs (pin 1) of IC1 for phase compensation and gain control to optimize the frequency response. When the mobile phone signal is detected by C3, the output of IC1 becomes high and low alternately according to the frequency of the signal as indicated by LED1. This triggers constable timer IC2 through capacitor C7. Capacitor C6 maintains the base bias of transistor T1 for fast switching action. The low-value timing components R6 and C9 produce very short time delay to avoid audio nuisance.

Mathematical Analysis

For the analysis of circuit only major parameters are considered. Which are listed as follows. Vcc = 9V The voltages across transistor are:VBE= 0.3VVCE= 7.65VVBC=8.7V The input and output DC voltages of ICs are:IC 3140 Input (pin 2) = 0.39V Output (pin6) =0.50VIC NE555- Input (pin 2) = 9V Output (pin6) =9V

PCB Layout and Schematic

Schematic and PCB layout are prepared by using Express PCB software.

Schematic:

PCB Layout:

Project Implementation

There are mainly three steps involved in project implementation Etching, Drilling and Soldering.The detailed steps are given below:

Etching:1) The mirror image of PCB layout is drown on the PCB with thick marking of permanent marker.2) Prepared the Etching solution in the etching machine. Ferrous chloride is used to prepare etching solution.3) Insert the PCB in the solution and set the timer of 15 minutes.4) Wash the PCB with cold water.5) Remove the marking of permanent marker using thiner.

Drilling:1) For Drilling the drill bit of 0.5 mm is used2) Drilling is completed with reference to PCB markings.

Soldering:1) Carefully solder components on PCB with proper lead spacing and lead length.2) For mounting the IC the IC holder is used to avoid damage of IC during soldering.

Testing

The circuit is tested for the detection of cell phone signals. For signal receiving wired antenna is used. During testing, all the major measurements are taken such as voltages, frequency etc. The circuit shows output over the range of 1-1.5 meter. Working is tested for outgoing as well as incoming calls on the cell phone. And also foe the text massages. The range can be improved by improving the antenna parameters.

ResultCell Phone Detector circuit detects the cell phone signals. And indicate them by blinking of LED and sound of the buzzer.It can detect the signals over the range of 1-1.5 meters.

Appendix CA3140 Datasheet:

BHARATI VIDYAPEETH COLLEGE OF ENGINEERING Page 13