Metallic pipe detector

Description: This circuit employs a 15-kHz oscillator coil. When metal is removed from the energy field, the oscillator voltage is rectified and compared to a reference. A decrease in oscillator voltage activates comparator IC2, causing D4 (LED) to turn off.

L1 consists of 500 turns of enameled copper wire with a diameter of 0.2 - 0.3 mm, wound on a ferrite rod that is 200 mm long and 10 mm in diameter.

The described circuit operates on the principle of an oscillator coil functioning at a frequency of 15 kHz. The oscillator coil, designated as L1, is constructed using 500 turns of enameled copper wire, which is wound around a ferrite rod. The choice of a ferrite rod enhances the magnetic field strength and improves the sensitivity of the coil to metallic objects. The wire's diameter of 0.2 - 0.3 mm strikes a balance between flexibility and conductivity, ensuring efficient operation.

When a metallic object enters the energy field generated by the oscillator, it influences the magnetic field, resulting in a change in the oscillator voltage. This voltage is then rectified, converting the AC signal to a DC signal suitable for further processing. A comparator, identified as IC2, continuously monitors the rectified voltage against a predefined reference voltage.

In the absence of a metallic object, the oscillator voltage remains stable. However, when the metallic object is withdrawn, a notable drop in the oscillator voltage occurs. This voltage drop is detected by the comparator IC2, which triggers a response. The output of the comparator is connected to a light-emitting diode (LED), labeled D4. When the comparator detects the drop in voltage, it activates the LED, which turns off, providing a visual indication that the metallic object has been removed from the energy field.

This circuit can be utilized in various applications, such as metal detection systems, security alarms, or proximity sensors, where the detection of metal presence or absence is critical. The design is straightforward yet effective, making it suitable for implementation in hobbyist projects or educational demonstrations in electronics.This circuit uses a 15-kHz oscillator coil. Whan metal placed ixi the energy field is withdrawn, the oscillator voltage is rectified and compared to a reference. A drop in oscillator voltage therefore operates comparator IC2 and D4 (LED) extinguishes.

L1= 500 turns enamelled copper wire. 0.2 - 0.3mm diameter. on ferrite rod 200mm long and 10 mm diameter.