Ijaz, SufyanArshad, Sumyya2014-02-172014-02-172013https://escholar.umt.edu.pk/handle/123456789/1040With the advancing technology, the cellular phone has become one of the important necessities of life. They are used even where they are required to be in switched-off mode only. We propose to detect the mobile phones in the places which strictly allow only OFF phones. The call and messages can be detected by catching the radio frequency disturbance, used for the transmission of data in GSM system, in the restricted premises. The AC waves captured by capacitor which acts as a loop antenna are then converted to voltage using differential property of op-amp to make the LED blink. And with the help of timer IC, the buzzer beeps. The device can act pretty well in a radius of approximately one meter. In the idle mode, OTD analysis can be used to detect the presence of the phone. This technique is implemented by the coordination of network providers and software installed in the hand set. There is another helpful technique using microwave sensors which combines the advantages of spectrum analyzer and wide-band frequency detectors. These sensors are used to detect radio frequencies of cell phone.enPhone DetectionBSc ThesisThesis