Metal Detector Using 555IC Full Making IC

Circuit Description:

1. 555 Timer IC:
   • The 555 timer is configured in astable mode to generate a continuous oscillating signal. This signal is fed to the search coil.
2. Resistors (R1, R2, R3):
   • R1 and R2 form a voltage divider to set the threshold voltage for the LM358 comparator. R3 is connected to the discharge pin (pin 7) of the 555 timer.
3. Capacitors (C1, C2):
   • C1 and C2 are timing capacitors for the 555 timer. They determine the frequency of the oscillating signal.
4. Inductor (Search Coil):
   • The search coil is connected to the output of the 555 timer and generates a magnetic field. When a metal object comes near the coil, it induces a change in the magnetic field.
5. Operational Amplifier (LM358):
   • The LM358 is configured as a comparator. It compares the voltage from the search coil with the threshold voltage set by the voltage divider.
6. Potentiometer (Variable Resistor):
   • The potentiometer adjusts the sensitivity of the metal detector by changing the threshold voltage.
7. Diodes (D1, D2):
   • D1 protects the 555 timer from reverse voltage. D2 prevents the discharge pin from pulling down the voltage on the threshold pin.
8. LED:
   • The LED lights up when a metal object is detected.
9. Buzzer:
   • The buzzer produces an audible signal when a metal object is detected