Elite Report Final(1)

ACHARYA NARENDRA DEV COLLEGE University of Delhi

ELITE PROJECT REPORT On

CELL PHONE DETECTOR

Submitted By SHASHANK NAGAR(YO-452) ABHISHEK BHADANA(YO-404) ANMOL DOGRA(YO-513) AVINASH KUMAR LAL(YO-451)

ACKNOWLEDGEMENT We would like to thank our Principal Dr. Savithri Singh for providing us with an opportunity to explore our ideas through summer fellowship ELITE program. We would like to thank Dr. Anju Agrawal and Ms. Gauri Ghai for accepting our idea of project and allowing us to be a part of Elite project 2018. We would like to thank our teacher in-charge Dr. Ravneet Kaur for guiding us at every stage of our project. We would also like to thank Dr. Amit Garg and Mr. Shani Kumar for providing us data useful for our project. We would also like to thank Dr. Monika Bhattacharya and Dr. Anita Kumari for supporting us throughout our project. We would like to thank our NonTeaching Staff for their support and cooperation. Finally, we would like to thank our parents and friends for boosting our morale.

CERTIFICATE This is to certify that the project titled ‘Cell Phone Detector’ was undertaken under the ELITE scheme of ACHARYA NARENDRA DEV COLLEGE, UNIVERSITY OF DELHI and implemented by us in the Electronics Laboratory. This work has not been submitted anywhere earlier, partially or fully.

Shashank Nagar YO-452 B. Sc (H) Electronics 3rd Semester

Dr. Anju Agarwal

Ms. Gauri Ghai

Mentor

Mentor

Department of Electronics

Department of Electronics

ABSTRACT Cell phones have become an integral part of today’s world. While it is important for people to stay connected with each other, however there needs to be a cap on the usage of mobiles. Over usage of cell phones can lead to security and health risks. It also leads to inefficiency at workplace and educational institutes due to lack of concentration of the user. The primary aim of the project is to develop a simple and low cost cell phone detector. This device is capable of sensing presence of cell phone in close range. It can also detect SMS. This device is compact and simple to use.

INTRODUCTION Cell phones have become primary source of communication today. They are not only used for communication via short messaging service (SMS), calls, emails and internet, but also for advanced applications such as remote health monitoring systems and security systems. Despite the advantages enjoyed by these advancements in mobile technology, there are threats that have been posed by their usage. Company data mining has been a big threat in the industry, where employees are able to access sensitive company information and share with the competitors. This led to the design and development of cell phone detectors which can be used in places where cell phone communication is prohibited or restricted. Criminal activities and attempted escape incidents have been organized by inmates in correctional facilities through the use of mobile phones. Life support machines in hospitals are also sensitive to the use of mobile phones. The use of mobile phones in such a facility leads to adverse repercussions to the life of the individual whose life depends on the proper functioning of the machines. This device can also find use at places where the use of mobile phones can either lead to failure of sensitive machines or is a nuisance such as petrol stations, airplanes, conference halls, examination halls, worship centers, etc.

Cell phones have become an important part of modern lifestyle in today’s world. Earlier, the primary purpose of mobile phone was to enable individual to stay connected with others. However with the advancement in technology it has also become a leading source of entertainment. Though social media applications provide an individual to express themselves, however due to over usage these applications become a major source of distraction. The availability of online television and games also contribute in the distracted behavior of individuals. This could cause distraction at work place and educational institutes, meetings, classrooms and during examination. The effectiveness of cell phone detectors is that they continually scan for the presence and usage of the cell phone and notify the security personnel.

WORKING PRINCIPLE The circuit has been designed to detect the presence of a mobile phone in close proximity. An LED or a buzzer can be used to indicate the presence of mobile phones. An ordinary RF detector using tuned LC circuits is not suitable for detecting signals in the GHz frequency band used in mobile phones. The transmission frequency of mobile phones ranges from 0.8 to 2.5 GHz. Thus Op-amp IC CA3130 (IC1) is used in the circuit as a current-to-voltage converter with capacitor of 100uF connected between its inverting and non-inverting inputs. The output CMOS transistor is capable of varying the output voltage within 10 mV of either supply voltage terminal. Therefore whenever the circuit receives a signal ranging between 0.8 to 2.5 GHz, it provides the output current to the LED. Hence we are able to detect our desired frequency range i.e. frequency range of a mobile phone. Two capacitors are connected in parallel to enable detection of mobile signals. These capacitors behave like a loop antenna for the system. When mobile receives a call or SMS then capacitors will detect the data transmission frequency or signals from the mobile phones. Two 100nF capacitors (C2 and C3), in parallel, are used for detecting RF signal from Mobile Phone.

Output of operational amplifier (op-amp) will go high or low due to generated current at input side of op-amp. These fluctuations are indicated through a LED which turns on through NPN transistors which are used as amplifiers.

LIST OF COMPONENTS USED SERIAL NO.

COMPONENT

1

CA 3130 Operational Amplifier

2

2.2M Resistor (2)

3

100K Resistor (1)

4

100nF Capacitor (4)

5

22pF Capacitor (2)

6

BC 547 Transistor

7

9 Volt Battery

8

100uF Capacitor

9

LED

10

1K Resistor (3)

CIRCUIT DETAILS CA3130)IC (OP-AMP)

It is excellent Op Amp that has very low input current requirements. Its output will be in the zero state in the off mode. CA3130 is the 15MHz BiMOS IC with MOSFET inputs and a bipolar output. This IC shows very high speed of performance and combines the advantage of both CMOS and bipolar transistors. The presence of PMOS transistors at the inputs results in common mode input voltage capacity down to 0.5 volts below the negative rail. So it is ideal in single supply applications. In cell phone detector circuit, this operational amplifier is configured as frequency detector or current to voltage converter and its output is connected to NPN and PNP transistors.

BC547

BC547 is a NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to base pin. BC547 has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. The maximum amount of current that could flow through the Collector pin is 100mA, hence we cannot connect loads that consume more than 100mA using this transistor. To bias a transistor we have to supply current to base pin, this current (IB) should be limited to 5mA. Here in the circuit it is used as an amplifier.

VARIABLE CAPACITOR

Rotary variable capacitor A variable capacitor is a capacitor whose capacitance can be varied according to the users requirement. Variable capacitors are often used in LC circuits to set or vary the resonance frequency, e.g. to tune a radio frequency we use variable capacitors thus they are also known as tuning capacitor or tuning condenser, e.g. for impedance matching in antenna tuners.

LED

A light-emitting diode (LED) is a p–n junction diode that emits light when activated.

It

has

a

two-lead

semiconductor

light

source.

When a

suitable current is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to a type of energy of the photon) is determined by the energy band gap of the semiconductor. LEDs are typically small (less than 1 mm2) and integrated optical components may be used to shape the radiation pattern.

IMPLEMENTATION OF THE PROJECT

The circuit was first made using the IC NE555, but the circuit didn't worked satisfactorily. LM358 IC was then used. The new circuit however was working but the IC was often getting heated up and also there was an inconsistent current flow to the circuit, which in the long run could damage the circuit. It was thus decided to implement the circuit using IC CA3130. This IC is an operational amplifier which is capable of detecting small change in current. A low value capacitor is connected to input of the IC. Since the IC used is quite efficient, even small change in capacitance is registered. The IC then sends an amplified value (~ 10mV) to the main capacitor which produces a high output state. This is indicated by an LED.

The circuit was initially implemented on breadboard. Initial circuits were attempted using larger breadboard area. This led to various problems in the circuit such as, change in capacitive reactance caused by voltage fluctuations. It was also realized that in this arrangement the capacitance used in the circuit were projecting incorrect values. Hence, it was realized that a compact circuit could rectify the above mentioned problems. The value of the variable capacitance used in the circuit could not be measured accurately due to lack of proper measuring device. Thus, for the initial stages fixed capacitors were used. Once the circuit became functional the fixed

capacitors were replaced with variable capacitor, the value of which were later measured using . Since the value of variable capacitor could now be measured, the circuit can be tuned to desired frequency range. The circuit thus designed is capable of detecting mobile phone up to a circumferential area with radius 5 to 6 meters. The range of this detector could be further improved by using high gain dipole antennas. With more time and resource this circuit can be coupled with a cell phone jammer to improve the detection range of the jammer.

CONCLUSION  In this project an attempt was made to design a cell phone detector with a range of 1.0 m using capacitor-resistor -circuit which can detect both outgoing and incoming calls even if the mobile is on silent mode. It works very efficiently. Fusion of new technology device with the existing tools makes it more trustworthy and reliable.  It is small, portable, light weight, easy to handle and operate. Overall the result of this concise study was optimistic, providing a good starting point for advanced investigations and improvement of the same.  This device can be used in classrooms during an examination where it is inevitable to switch off the phones.  It can also be used while conducting confidential meetings.  It can also be used in temples, high alert areas and even in the army bases.

 If we make some changes to the circuit then this device can also work as a network jammer.

REFERNCES 1.Ajasa, A.; Shoewu, O. and Nwamina, P. (2014). “Design and Development of a Mobile Phone Signal Detector”, Pacific Journal of Science and Technology, 15(2):167-172. 2.Alonge, M. (2003). Assessment and Examination: the Pathways to Educational Development, 9th Inaugural Lecture. Ado-Ekiti: Ekiti State University. 3. Blurton, C. (2002). New Directions of ICT Use in Education. [Online] Available: http://www.unesco.org/education/educprog/lwf/dl/dict.pdf (June 10, 2016). 4. www.Alldatasheets.com