Long Range Russian Pirate PI Metal Detector(Ultra high sensitivity)

Long Range Russian pirate pulse induction Metal Detector

Introduction

This circuit is a metal detector capable of detecting large metallic objects. at a depth of 2m to 3m. It depends on the size of the object, and often on the type of soil. Construction is very easy to implement even for a beginner. The necessary components are easy to find everywhere. This detector has the ability to detect a gold coin of 20mm and a thickness of 1.5mm and a depth of 90cm. The two present frequencies are the one that is generated by the circuit and the one that is returning for comparison. By placing the coil near a metallic object the returning frequency is changed. Those two frequencies are the subject of comparison by our circuit. At modern metal detectors, the reference generator operates at a frequency that has different magnitude from that which appears in the field of the search coil.

Types of metal detector

  1. Beat frequency oscillation

  2. VLF(very low frequency)

  3. PI(pulse induction)

BEAT FREQUENCY OSCILLATION

One of the most common metal detectors, this is the type that is mostly used in electronics stores. It is capable of looking for items situated approximately 2 feet underground. Each and every metal detector makes use of twisted copper rolled all over a ring that is made from steel or iron.

The metal detectors feature one big ring that is fastened to its base. Furthermore, it has another smaller ring fastened a bit higher. These coils are both linked to the oscillators that can produce a frequency.

The coils work at a differing frequency, though. This particular disparity is the factor that the metal detector perceives and transmits to the speakers. The speakers look like a head ornament and they generate a noticeable, constant hum that can be perceived by the user employing the detector.

As soon as the base coil passes over a metallic item, the electromagnetics interaction brings about an intrusion in the transmission of frequency. This intrusion is then employed as evidence of the presence of a metallic item

VLF (very low frequency)

This kind of detector is one of the most widely-used since it has a variety of uses due in part to technological advancements. It has 2 spherical wire coils which are called a transmitter and receiver. The transmitter is employed to release a magnetic field with low frequency into the ground that is utilized for hunting treasures.

The receiver, meanwhile, is employed for its ability to pick up magnetic signals from an item that is located under the ground. As soon as the signal occurs, a sound will be audible.

In addition, this kind of detector has an electric circuit called a tuner, and its purpose is to send signals to the receiver of the device. For gold and silver prospecting, users can filter out signals that come from steel, iron, and aluminum so they can focus more on their goal item.

PULSE INDUCTION

The pulse induction kind is specifically employed to look deep into the surface for relics, gold, and treasure. The larger-sized models are employed at checkpoints that need security for firearm/weapon detection. A single-coil is employed for this purpose and it transmits a magnetic field into the ground.

This kind of detector changes models to assist users in listening for the signal that was found and can distinguish between accidental external signals from its environment, or sent signals. Furthermore, this type of detector is pricier compared to the others.

Circuit diagram

Components required

• IC – NE555 – 1no
• IC – TL072 – 1no
• MOSFET – IRF740 – 1no
• Transistor – BC557 – 1no
• Transistor– BC547 – 1no
• Diode – 1N4148 – 2 nos
• Resistor – 1.5k – 1no
• Resistor – 100k – 1no
• Resistor – 1k – 1no
• Resistor – 470k – 1no
• Resistor – 47k – 1no
• Resistor – 470ohm – 1no
• Resistor – 150ohm – 1no
• Resistor – 100ohm – 1no
• Resistor – 220ohm(1w) – 1no
• Resistor – 390ohm(0.5w) – 1no
• Resistor – 68k(2w) – 2nos
• Resistor – 120k – 1no
• Resistor – 2M(0.25w) – 1no
• Resistor – 10ohm(0.25w) – 1no
• Variable resistor – 100k – 1no
• Capacitor – 2200uf/25 – 1no
• Capacitor – 100nf – 2nos
• Capacitor – 1uf/25v – 2nos
• Capacitor – 10uf/25v – 2nos
• Capacitor – 1nf – 1no
• Speaker – 0.5w,8ohm – 1no
• Power supply – 9v – 1no

Coil construction

 The coil should would on a plastic tube with an external diameter of 200mm. The coil should contain 25 turns of 24SWG and it should be wrapped in aluminium foil.

Pin configuration of IC TL072

IC TL072 pin configuration