Please tell the metal detector vk557 vegakit project and it's procedure

Metal detector project


This circuit is very useful for the metal detector safety check. Metal detectors available on the market are quite expensive.

This metal detector can be used to detect metallic objects of slightly large size. we used a detection coil. This coil should be kept close to metal objects for detection. Circuit Input is  colpitt's R.F. Oscillator Range. The detection coil forms parts of the tuned oscillator.

Working Principle:
When the coil approaches a metal object, a magnetic energy is observed and the oscillator does not work. Then, the transistor end leads and the buzzer are activated. Use a 9-volt battery. After connecting the battery, adjust the preset circuit of 4.7k, simply stop playing.


PARTS LIST:-

CAPACITORS
C3 – 220PF
C5 – 12KPF/ 100V (.012/25V)
C1,C6 – .1PF (104) 100 KPF
C4 – 270PF/100V
C2 – 1KPF (102).001PF
C7 – 100/25V


MISCELLANEOUS

Buzzer – VK 27 CT (S)
PCB – VK 557 PCB
COIL1 – Metal Detector Coil
LED1 – 5MM Red LED
Supply – 9v Snapper


TRANSISTORS
Q1,2,3,4 – BC 547 PH

DIODE
D1,2,3,4 – IN 4148


RESISTORS
R6 – 2K2
R1,R4 – 56K
R7,R9 – 680E
R8 – 15K
R3 – 22K
R5 – 2K7
R2 – 3K3
P1 – 5K 3386 Trim

A metal detector is an electronic instrument that detects the presence of metal near. Metal detectors are useful for finding hidden metal inclusions inside objects, or metal objects buried underground. They often consist of a handheld unit with a sensor probe that can be swept over the floor or other objects. If the sensor approaches a metal part, this is indicated by a changing tone on the headphones or a needle moving over an indicator. Usually, the device gives some indication of the distance; The closer the metal is, the higher the pitch in the handset or the higher the needle. Another common type is stationary metal detectors "on foot" used for detecting security at access points in prisons, courts and airports to detect metal weapons hidden in a person's body.

The simplest form of a metal detector consists of an oscillator that produces an alternating current that passes through a coil that produces an alternating magnetic field. If an electrically conductive metal part is near the coil, the eddy currents will be induced in the metal, and this produces its own magnetic field. If another coil is used to measure the magnetic field (acting as a magnetometer), the change in the magnetic field due to the metal object can be detected.

The earliest detectors of industrial metals were developed in the 1960s and were widely used for prospecting for minerals and other industrial applications. Uses include detection of landmines, detection of weapons such as knives and guns (especially in airport security), geophysical prospecting, archaeology and treasure hunting. Metal detectors are also used to detect foreign bodies in food and in the construction industry to detect reinforcing steel bars in concrete and pipes and cables buried in walls and floors.