shared wiring

This metal detector electronic project schematic circuit is designed using a simple 555 timer integrated circuit . As you can see in the schematic circuit , this metal detector electronic project requires few external electronic parts . This circuit detects metal and also magnets.

Metal Detector with 555 Timer Circuit Daigram

When a magnet is brought close to the 10mH choke, the output frequency changes. This metal detector project can be powered from a power supply that can provide an output DC voltage between 6 an 12 volt . If a metal is closer to the L1 coil , will produce a change of output oscillation frequency, that will generate a sound in the 8 ohms speaker

These metal detector circuit diagram is based on the TDA0161 monolithic integrated circuit , designed for metallic body detection by detecting the variations in high frequency Eddy current losses. For detecting metals , TDA0161 require an external LC tuned circuit .

Metal Detector Circuit diagram

Output signal is determined by supply current changes. Independent of supply voltage, this current is high or low according to the presence or the absence of a close metallic object. This metal detector circuit use two LEDs , which offer an visual indication of presence or absence at a metals ,around the coil . To adjust the circuit you need to make sure there is no metal near the coil and then set the fine adjustment to a "Mid position". After that you need to adjust the course adjustment to turn on the LED and , adjust the fine adjustment to turn off the LED.

This detector electronic circuit operates over a wide range input voltage of 4 -35 volts .  If you want you can use other values for the Cx capacitor and for L1 inductor  ( changing this value will affect the frequency oscillation and the detection range ) .