Electronics-I Lab GSM Signal DetectorEE217

ELETRONICS-IPROJECT REPORT

GSM SIGNAL DETECTOR

Prepared By: Muhammad Abdul Fareh Khan

Muhammad SuhaibTayyab Hussain Hashmi

Section-A

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Electronics-I Lab GSM Signal DetectorEE217

CONTENTS

Sr.no Content Page No.

1 Introduction 3

2 Working Principle 4

3 Circuit Diagram 6

4 Components’ Description 7

5 Applications 10

6 Cost 13

7 LM358 Datasheet 14

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Electronics-I Lab GSM Signal DetectorEE217

INTRODUCTION

GSM Detector is the ideal solution for organizations and companies

where the use of mobile phones is not allowed in certain cases. It is a

device that detects mobile communications and gives a customizable

warning to the person using the phone or another supervising person.

This way, the person that used a mobile phone, can be notified that this

is prohibited.

The dangers of electromagnetic interference (EMI) by mobile phones

on sensitive electronic equipment are well known. There are also

factors of safety and hinder that we should consider. In practice the

warning signs to prevent use of mobile phone are often ignored. For

this, the GSM-detector is the ideal solution. The GSM-detector gives a

warning when it detects the use of mobile phones where it is

inappropriate or dangerous.

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Electronics-I Lab GSM Signal DetectorEE217

WORKING PRINCIPLE

The GSM detector constantly detects the use of mobile phones. When a

mobile phone is used, a red LED will flash and an alarm and/or a

spoken message will sound, asking the user to switch off the mobile

phone.

The circuit is basically a simple high gain non inverting AC amplifier,

built around the IC LM 358. Both of its op-amps are incorporated.

As mentioned in the earlier part of this article, the op-amp is

configured as a high gain non inverting amplifier, where the input is

received at the pin which is the inverting input of the op amp.

The RF disturbances in the air is received by the antenna and fed to the

inverting input of the op-amp which is amplified by the circuit to some

specified level depending on the value of the feedback resistor across

the output and the inverting input of the op-amp.

Increasing the value of this resistor increases the sensitivity of the

circuit, however too much sensitivity can make the circuit unstable and

induce oscillations.

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Electronics-I Lab GSM Signal DetectorEE217

The amplified signal is fed to the input of the next stage which is just a

replica of the previous stage. 

Here the relatively weaker signals from the first stage is further

enhanced and made stronger so that now it may be fed to the third

stage for repeating the actions that is for further amplification until the

last stage whose output illuminate an LED, displaying the presence of

even the minutest possible RF disturbance in the air.

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Electronics-I Lab GSM Signal DetectorEE217

CIRCUIT DIAGRAM

COMPONENTS’ DESCRIPTION6

Electronics-I Lab GSM Signal DetectorEE217

1) Battery (9V) : A DC power source to operate the circuit.

2) IC LM3248: Dual op-amp.

3) Antenna: To pick up the GSM signals.

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Electronics-I Lab GSM Signal DetectorEE217

4) Diode: To allow the flow of current in one direction only.

5) Buzzer: Indicate by producing sound when GSM signal is detected.

6) Resistors: Constant and variable (potentiometer).

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Electronics-I Lab GSM Signal DetectorEE217

7) Capacitors: A passive two-terminal electrical component used to store energy in an electric field.

8) LEDs: Light Emitting Diode used as an indicator.

APPLICATIONS9

Electronics-I Lab GSM Signal DetectorEE217

School / Universities

During tests and exams the use of mobile phones is prohibited, for the students could use it to send answers among each other.

By using a gsm-detector this kind of fraud is prohibited. The presence of a gsm-detector can work in a preventing way, because when a gsm-detector is present, the use of mobile phones does not stay unnoticed

Cinemas

In a cinema the use of a mobile phone is undesired. Being called by someone during a movie is of course very bothering for other people.

With a gsm-detector the use of mobile phones is detected, so the visitor can be informed that this is not allowed.

Theatres

Just like with a cinema, in theatres the use of mobile phones is not allowed. The gsm-detector can be used to prevent use.

Petrol stations

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Electronics-I Lab GSM Signal DetectorEE217

When tanking at a petrol station, the use of mobile phones is prohibited, because the mobile signals can interfere with the tanking equipment and because a small spark within the mobile phone could set fire to possible gasoline vapour.

With the gsm-detector this prohibition is pointed out to the tanking customer.

Airplanes

In airplanes the use of mobile phones is prohibited, for it could interfere with the equipment in the airplane. All the while phones are still used illegally, especially in restrooms. By installing a gsm-detector there, this can be prevented.

Conference rooms

It is often distracting to be called during a meeting. Also, confidential conversation could be overheard by using cell phones, especially by those with a spy function (when someone calls that phone it automatically is picked up without ringing, so that the person on the other end of the line can hear conversations in the room where the spy phone is placed).

By using a gsm-detector you can be assured that this is not the case.

Hospitals

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Electronics-I Lab GSM Signal DetectorEE217

The signals emitted by mobile phones can interfere with some electronic equipment inside the hospital. This could have fatal consequences. The gsm-detector can be placed in any area where the use of mobile phones could interfere with sensitive devices. The audio alarm will sound when a phone is used and this way, the person should immediately switch off his/her phone.

Prisons

In prisons the use of mobile phones is not allowed. It could occur anyway. By using the gsm-detector the staff can be notified when a mobile phone is used inside the facility.

Power plants

Power plants contain -just like hospitals- a lot of electronic devices that are sensitive for interference by mobile phones. Therefore, it is prohibited to use mobile phones there. Use a gsm-detector to inspect this.

Petrochemical industry

Just like in power plants, the petrochemical industry makes use of sensitive equipments. In this branch of industry the materials that are being processed are often highly flammable or explosive. Tiny sparks that can occur within a gsm telephone could lead to explosions. With the gsm-detector the unauthorized use of mobile phones can be traced.

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Electronics-I Lab GSM Signal DetectorEE217

COST

Sr. Description

Quantity

Unit Price

Amount (Rs)

1 DC Battery (9V) 1 35.00 35.00

2 Resistors (47,330,1K,220K) ohms 5 1.00 5.00

3 Capacitors (100,0.1) uF 2 4.00 8.004 LED 1 5.00 5.00

5 Diode (4018) 1 5.00 5.00

6 LM358 Op-amp IC 1 25.00 25.00

7 Antenna 1 70.00 70.008 Buzzer DC (9V) 1 15.00 15.00

  Total     168.00

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