HIDDEN ACTIVE CELL PHONE DETECTOR

PRESENTED BY-

SAYANTANI PALANUJA NANDYSANJEET KUMAR JHASUSHMITA ROYPRIYADARSHINI DEY

CONTENTSo Introductiono Design Objectiveso Equipmentso Frequency Range Detectoro Working Principleo Basic block diagramo Circuit Designo Components Description-

Op-Amp IC1 CA3130 NE555 Timer Capacitors Resistors Transistorso Applicationso Conclusiono Future Plan

INTRODUCTION

Main scope of project is to sense the presence of an activated mobile phone from a distance of one-and-a-half meters to prevent the use in the examination halls, confidential rooms etc.

RF detector using tuned LC circuits is formed for detecting signals in the GHz frequency.

Transmission frequency of mobile phone ranges from 0.9 to 3 GHz.

As the cell phone sends or receives a message or call, it sends off a signal. This signal is detected by our circuit and will cause the LED to blink and buzzer to sound.

This simple circuit can detect any cell phone activities like sending or receiving calls or SMS, or any type of data transmission.

The aim of the circuit is to receive the RF signal from mobiles & detects its presence by alarming the sound.

DESIGN OBJECTIVES

The main objective includes building a mobile detector to locate a phone within one and a half radius and to jam GSM signal within 5 to 10 meters radius.

EQUIPMENTS

Resistors

Capacitors

Transistors

Op-Amp

LED

IC 555 Timer

Piezo buzzer

Battery

5 inch Antenna

On-Off Switch

FREQUENCY RANGE DETECTOR

The transmission frequency of mobile phones ranges from 0.9 to 3 GHz with a wavelength of 3.3 to 10 cm. So a circuit detecting gigahertz signals is required for a mobile bug.

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.

WORKING PRINCIPLE We use a disk capacitor C4(220nF), which will capture

the signals from the active cell phone transmission. The disk capacitor along with its leads form a small gigahertz loop to catch the signals.

The IC CA3130 is an op-amp, that is used in this circuit as a current to voltage converter. The capacitor C4 leads are the input for the IC1.

The IC1 provides the base voltage to the transistor Q1. 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. 

We are using a 5 inch antenna.

BASIC BLOCK DIAGRAM

COMPONENTS DESCRIPTION

OP AMP IC1 CA3130

Op-amp IC CA3130 (IC1) is used in the circuit as a current-to voltage converter ..

NE555 TIMER IC

A 555 timer in mono-stable mode along with a high gain op amp is used to detect Giga Hertz induced signals so produced by an active cell phone with in closer proximity t o sound a buzzer alarm.

TRANSISTORS

One transistor is used, BC548

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..

RESISTORS

15 kΩ, 12 kΩ, 1 k Ω, 100kΩ, 2.2 MΩ.

Total six resistors are there.15 k Ω is connected with pin no 6

and 12 k Ω is connected with pin no 2 of the NE555 timer.

CAPACITORS

0.01 µF, 4.7 µF, 0.1 µF, 0.22 µF, 22 pF, 47 pF, 100 µF.

How does it work? To detect the signal , the sensor part should be like an

aerial..

The capacitor creates the fields, store the energy

and transfers this energy in the form of mini current to

the input of the IC1 which will upset the balanced input

of IC1 and converts the current into output voltages..

Circuit Design

APPLICATIONS

1) It can be used to avoid the usage of mobile phones in examination halls, seminar halls, quizzes etc.

2) It can be used to avoid video transmission in a secret or private meeting.

3) It can be used for military and civil defense purposes to detect mobile phones by increasing its radius of range.

4) It can be used in hospitals and airplanes where, mobile signals interfere with the electronic equipment which may have fatal consequences.

CONCLUSION

• This cell phone detector circuit can sense the presence of an activated mobile cell phone from a distance of one and-a-half meters..

• This cellular phone detector can detect any activity of a mobile phone : incoming or outgoing SMS , video transmission or voice transmission..

• This cellular phone detector electronic circuit diagram can be used to verify the presence of an active cellular phone in the tested area..

FUTURE PLAN

Over the allotted period we were able to progress with our circuitry but it is far from complete.

So in future we expect to complete the circuit and implement a cellular detector through our circuit.

THANK YOU