Transcript Document

MOBILE PHONE
DETECTOR
BYAKSHAY.A.JADHAV
(es12b1004)
Indian Institute of Technology
Hyderabad
Introduction
This project is a simple cell phone detector project. This handy cell
phone detector, pocket size mobile transmission sniffer can sense
the presence of an active cell phone in a radius of 1m-1.5m.
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 is the basic principle of the project.
This simple circuit can detect any cellphone activities like sending or
receiving calls or SMS, or any type of data transmission.
Circuit Diagram :
Working :
The transmission frequency of a mobile ranges from 0.9GHz to
3GHz.So a circuit capable of detecting gigahertz signals is needed.
So 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.
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.
As the capacitor C4 receives the signal, the output of IC1 becomes
high and low alternately depending on the frequency of the signal.
This triggers the timer IC2 through capacitor C6 and the LED starts
blinking and the piezoelectric buzzer starts sounding due to the
timing components R5(10k) and C7(47uF) which set the ON time to
1 second.
Uses :
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.
And many more uses…
THANK YOU!