Metal Detector Circuit

The metal detector is built with one 100µh coil that has 40 mm in diameter and is made of 50 turns 0 4 mm wire.

Metal detector circuit.

Below is the complete electronic circuit for the metal detector that we are building. The other day when i was searching instructables i come across on interesting and simple circuit for metal detector. Instructable that inspire me to do this project was this one. Now the two frequency will be different there will be no cancelling and the radio produces a hissing sound.

It is build with 555 coil and few other components. There are three main parts in the metal detector circuit. These metal objects are very useful to detect the presence of any hidden object. The lc circuit the proximity sensor output led and the buzzer.

The metal detector circuit is the mandatory part of the security. Some circuits would be illegal to operate in most countries and others are dangerous to construct and should not be attempted by the inexperienced. When a signal that oscillates at several khz passes through this circuit the signal creates an electric field around the coil. Remember the coil wound here is a air cored one so when a metal piece is brought near the coil the metal piece acts as a core for the air cored inductor.

Metal detector circuit diagrams and projects note that all these links are external and we cannot provide support on the circuits or offer any guarantees to their accuracy. When the metal detector circuit is placed near to a metal object the inductance of its coil changes and so do the frequency of oscillations. The coil and the capacitor c1 which are connected in parallel will form the lc circuit. This means a metal object is detected.

A metal detector is a circuit that senses any metallic object close by. Inductor l1 the inductor l1 forms a parallel circuit with the capacitor c1 to form an lc parallel circuit. One oscillator is working at 455 khz and other at a slighter lower frequency of 452 khz. Now as mentioned earlier in previous section a metal core inductor has a high inductance value over a air cored one.

A simple metal detector uses a 555 timer ic. Cs209a has one oscillator wich forms a lc circuit the inductance of the coil will change when it is near metal objects.