Project report of Cell phone detector circuit
- 1. CELL PHONE DETECTOR PROJECT REPORT OPERATIONAL AMPLIFIERS & OSCILLATORS `GROUP MEMBERS Mohsin Meraj 2012-EE-313 Shaheryar Farrukh 2012-EE-314 Hafiz S.M Rasheed 2012-EE-325 Moin Aman 2012-EE-336 Submitted to: Miss Sabeen
- 2. ACKNOWLEDGEMENT We would begin to thank with ALLAH S.W.T without whose help we would have been unable to prepare the project presented. We take this opportunity to express our profound gratitude and deep regards to our guide Miss Sabeen for her exemplary guidance, monitoring and encouragement throughout the course of this project. We also take this opportunity to express a deep sense of gratitude to Sir Asif, for his cordial support, valuable information and guidance, which helped us in completing this task through various stages. Finally we extend our gratefulness to one and all who are directly or indirectly involved in the successful completion of this project report. Mohsin Meraj (2012-EE-313) Shaheryar Farrukh (2012-EE-314) Hafiz S.M Rasheed (2012-EE-325) Moin Aman (2012-EE-336)
- 3. 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. Assemble the circuit on a general purpose PCB as compact as possible and enclose in a small box like junk mobile case. As mentioned earlier, capacitor C3 should have a lead length of 18 mm with lead spacing of 8 mm. Carefully solder the capacitor in standing position with equal spacing of the leads. The response can be optimized by trimming the lead length of C3 for the desired frequency. You may use a short telescopic type antenna. Use the miniature 12V battery of a remote control and a small buzzer to make the gadget pocket-size. The unit will give the warning indication if someone uses Mobile phone within a radius of 1.5 meters.
- 4. Introduction Overview As increase in the technology in the world using the electronic equipments are being used in a wrong way like, in the examination halls and confidential rooms. To avoid this we are introducing a project called CELLPHONE DETECTOR 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. Problem Statement Previously, there was no technology to detect the cell phones in the examination hall and in cell phone restricted areas. There is manual checking and there is still a chance of having the cell phone with the person if he is not checked properly. So to avoid this problem, an automatic detection of cell phone is introduced. Motivation Cell phones are used in good way and also in a bad way. When the class is going on, students intend to use their cell phones and not listening to what is being taught. These days, students are also carrying their cell phones to the examination halls to copy which would help them to get good marks. To avoid this problem, the cell phone detector is introduced.
- 5. Hardware Description CIRCUIT DIAGRAM COMPONENTS LIST RESISTOR R1 ________2.2M R2 ________100K R3 ________2.2M R4 ________1K R5________12K R6________15K CAPACITOR C1 ________22pF C2 ________22pF C3 ________0.22μF C4 ________100μF
- 6. C5_________47pF C6 _________0.1μF C7_________ 0.1μF C8_________ 0.01μF C9__________4.7μF IC CA3130 IC NE555 T1 BC548 LED ANTENNA PIEZO BUZZER 5 INCH LONG ANTENNA ON/OFF SWITCH POWER SUPPLY COMPONENTS ANALYSIS IC CA 3130 Figure 2.2.6 IC CA 3130 This IC is a 15 MHz BiMOS Operational amplifier with MOSFET inputs and Bipolar output. The inputs contain MOSFET transistors to provide very
- 7. high input impedance and very low input current as low as 10pA. It has high speed of performance and suitable for low input current applications. CA3130A and CA3130 are op amps that combine the advantage of both CMOS and bipolar transistors. Gate-protected P-Channel MOSFET (PMOS) transistors are used in the input circuit to provide very-high-input impedance, very-low-input current and exceptional speed performance. The use of PMOS transistors in the input stage results in common-mode input-voltage capability down to0.5V below the negative-supply terminal, an important attribute in single-supply applications. A CMOS transistor-pair, capable of swinging the output voltage to within 10mV of either supply-voltage terminal (at very high values of load impedance), is employed as the output circuit. IC NE555 TIMER Figure 2.2.7 IC NE 555 Timer The NE555 IC is a highly stable controller capable of producing accurate timing pulses. With a monostable operation, the time delay is controlled by one external resistor and one capacitor. With an astable operation, the frequency and duty cycle are accurately controlled by two external resistors and one capacitor.
- 8. PIEZO BUZZER Piezoelectricity is the ability of some materials (notably crystals and certain ceramics, including bone) to generate an electric field or electric potential in response to applied mechanical stress. The effect is closely related to a change of polarization density within the material's volume. If the material is not short-circuited, the applied stress induces a voltage across the material. The word is derived from the Greek piezo or piezein, which means to squeeze or press. A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as microwave ovens, or game shows. It most commonly consists of a number of switches or sensors connected to a control unit that determines if and which button was pushed or a preset time has lapsed, and usually illuminates a light on the appropriate button or control panel, and sounds a warning in the form of a continuous or intermittent buzzing or beeping sound. Hardware Implementation BASIC CONCEPT AND WORKING OF CELLPHONE DETECTOR Purpose of the circuit This circuit is intended to detect unauthorized use of mobile phones in examination halls, confidential rooms etc. It also helps to detect unauthorized
- 9. video and audio recordings. It detects the signal from mobile phones even if it is kept in the silent mode. It also detects SMS. CONCEPT Mobile phone uses RF with a wavelength of 30cm at 872 to 2170 MHz. That is the signal is high frequency with huge energy. When the mobile phone is active, it transmits the signal in the form of sine wave which passes through the space. The encoded audio/video signal contains electromagnetic radiation which is picked up by the receiver in the base station. Mobile phone system is referred to as “Cellular Telephone system” because the coverage area is divided into “cells” each of which has a base station. The transmitter power of the modern 2G antenna in the base station is 20-100 watts. When a GSM (Global System of Mobile communication) digital phone is transmitting, the signal is time shared with 7 other users. That is at any one second, each of the 8 users on the same frequency is allotted 1/8 of the time and the signal is reconstituted by the receiver to form the speech. Peak power output of a mobile phone corresponds to 2 watts with an average of 250 milli watts of continuous power. Each handset with in a ‘cell’ is allotted a particular frequency for its use. The mobile phone transmits short signals at regular intervals to register its availability to the nearest base station. The network data base stores the information transmitted by the mobile phone. If the mobile phone moves from one cell to another, it will keep the connection with the base station having strongest transmission. Mobile phone always tries to make connection with the available base station. That is why, the back light of the phone turns on intermittently while traveling. This will cause severe battery drain. So in long journeys, battery will flat within a few hours. AM Radio uses frequencies between 180 kHz and 1.6 MHz, FM radio uses 88 to 180 MHz, TV uses 470 to 854 MHz. Waves at higher frequencies but within the RF region is called Micro waves. Mobile phone uses high frequency RF wave in the micro wave region carrying huge amount of electromagnetic
- 10. energy. That is why burning sensation develops in the ear if the mobile is used for a long period. Just like a micro wave oven, mobile phone is ‘cooking’ the tissues in the ear. RF radiation from the phone causes oscillation of polar molecules like water in the tissues. This generates heat through friction just like the principle of microwave oven. The strongest radiation from the mobile phone is about 2 watts which can make connection with a base station located 2 to 3 km away. How the circuit works? Ordinary LC (Coil-Capacitor) circuits are used to detect low frequency radiation in the AM and FM bands. The tuned tank circuit having a coil and a variable capacitor retrieve the signal from the carrier wave. But such LC circuits cannot detect high frequency waves near the microwave region. Hence in the circuit, a capacitor is used to detect RF from mobile phone considering that, a capacitor can store energy even from an outside source and oscillate like LC circuit. C 0.22 UF IC1 CA 3130 7 IC1 3 2 4 6 R2 100K R3 1 M Use of capacitor R1 3.9 M LED Red BUZZER 9 V Battery + C1 R5 100R R4 100 R C2 100 UF 25V 0.1 A capacitor has two electrodes separated by a ‘dielectric’ like paper, mica etc. The non polarized disc capacitor is used to pass AC and not DC. Capacitor
- 11. can store energy and pass AC signals during discharge. 0.22μF capacitor is selected because it is a low value one and has large surface area to accept energy from the mobile radiation. To detect the signal, the sensor part should be like an aerial. So the capacitor is arranged as a mini loop aerial (similar to the dipole antenna used in TV).In short with this arrangement, the capacitor works like an air core coil with ability to oscillate and discharge current. How the capacitor senses RF? One lead of the capacitor gets DC from the positive rail and the other lead goes to the negative input of IC1. So the capacitor gets energy for storage. This energy is applied to the inputs of IC1 so that the inputs of IC are almost balanced with 1.4 volts. In this state output is zero. But at any time IC can give a high output if a small current is induced to its inputs. There a natural electromagnetic field around the capacitor caused by the 50Hz from electrical wiring. When the mobile phone radiates high energy pulsations, capacitor oscillates and release energy in the inputs of IC. This oscillation is indicated by the flashing of the LED and beeping of Buzzer. In short, capacitor carries energy and is in an electromagnetic field. So a slight change in field caused by the RF from phone will disturb the field and forces the capacitor to release energy. APPLICATION 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. It is useful where the use of mobile phone is prohibited like petrol pumps and gas stations, historical places, religious places and court of laws.
- 12. CONCLUSION and FUTURE SCOPE CONCLUSION This 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. FUTURE SCOPE Trying to increase the detecting range of cell phone detector to few more meters for observing wide range of area. References 1. www.google.com 2. www.wikipedia.org 3. www.pdfmachine.com 4. www.efymag.com 5. www.datasheets4u.com
- 14. IC NE555 TIMER:
- 15. PIEZO BUZZER: