Graduate Profiles 2012 - National University of Science and ...

CONCEALED WEAPON DETECTIONOur project is in the form of a walk-through gate. We are utilizing the technique ofInductive Magnetic Field for metal detection in our project. It is further classified intothree categories depending upon the frequency of operation and the input source. Weare utilizing the Beat Frequency method for metal detection in our project. A certainfrequency is generated by a colpitt‘s oscillator which is balanced by another oscillator.The search coil is the inductor used in the colpitt‘s oscillator. When a metal is broughtnear to the search coil its inductance varies and the frequency of colpitt‘s oscillator ischanged. The difference of the frequencies is amplified and is used to trigger thebuzzer.In our project we have used colpitt‘s oscillator of frequency 100-130 kHz. Anintermediate frequency transformer (IFT) of 450 kHz is used. Its frequency is lowered tobalance the collpit‘s oscillator by shunting the coil with a variable capacitor. Sixdetection circuits are developed for six of the zones. The signal from the detectorcircuits is fed into the bar display circuit which identifies the zone and shows thestrength of signal. A waveform matrix displays the difference of frequencies. Amicrocontroller part has also been developed in order to classify the size of detectedmetal. It has been interfaced with computer via serial port and displays the size ofdetected metal on hyper terminal.A prototype of the Concealed Weapon Detection Walk-Through Gate has beendesigned and built. Main gate structure is made of wood. The system consists ofwooden gate, detection circuits, power supplies, bar display circuits, waveform matrixand the microcontroller hardware.Syndicate Members: RizwanZafarRamzan AliSarmad GhafoorHammad SadiqSupervisor:Dr. Abdul Ghafoor25