Simple Metal Detector Circuit using IC 555

This is Simple Metal Detector Circuit using IC 555

It uses IC 555 chip which works like small clock and makes signal to help find metal and magnet

It is easy to build and good for beginners.

Circuit Working:

Parts List:

This article show how simple metal detector work using IC 555.

IC 555 make magnetic field that keep changing means oscillating.

When metal comes near the coil it break magnetic field and changes the frequency.

Speaker hear this change and makes sound.

How circuit work:

IC 555 work as astable multivibrator and give square wave at pin 3.

Resistor R1 and capacitor C1 set the frequency.

C1 and R1 together control how fast wave come means oscillation.

Speaker make sound when frequency changes which is shown in circuit diagram.

Capacitor C2 stop noise and help circuit work better.

Coil is wire wrapped around shape and when current goes through it, makes magnetic field.

Coil size and wire turns decide frequency.

When metal come close frequency changes and speaker sound get higher.

Formulas:

IC 555 in astable mode can make metal detector.

It creates changing oscillating the electromagnetic field.

When metal come near it changes frequency of this field.

That is how metal is found.

Here is formula used for this type of circuit:

Frequency (f) formula:

f = 1.44 / (R1 + 2×R2) × C

where:

• R1 and R2 are the resistors in circuit
• C is the capacitor in circuit

This formula help to find and change frequency of IC 555.

By changing R1, R2, C and coil we can make detector more sensitive and better at finding metal.

How to Build:

To build a Simple Metal Detector Circuit using IC 555 below mentioned are the steps for connections:

• Take all parts as shown in diagram.
• Connect pin 1 of IC 555 to ground.
• Connect pin 2 to pin 6.
• Connect pin 3 to ground using capacitor C1 and 8 ohm speaker.
• Connect pin 4 to +6V to +12V supply.
• Connect pin 6 to one side of resistor R1 and other side to + supply.
• Connect capacitor C2 from pin 2 to ground.
• Connect coil 10mH and capacitor C3 between pin 2 and pin 6.
• Connect pin 8 to +6V to +12V supply.

Extra Note:

• Circuit can act different if ground is not good.
• We may need to change R1 to make it work better.
• Bigger C1 or coil is more sensitive but also more noise.
• This circuit can not tell different metal types.

Conclusion:

Simple Metal Detector Circuit using IC 555 makes signal that change when metal is near.

It help detect metal but cannot say which metal it is.

This circuit is good for basic understanding.

References:

Metal detector