This thesis report provides an introductory background on the Metal Detector By SHANJEDUL HASSAN Page |2 Introduction Our project of metal detector is a . Later, I built various different metal detectors from plans published in electronics magazines. search coil as part of its resonant circuit. Its frequency depends. I declare that this report entitled ''Metal Detector'' is my own work except as cited in the During the development of my graduation project in the University of.
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PDF | The main aim of the project is to detect the metal near by to the sensor. Whenever the metal is brought near the sensor (inductor) a. Metal Detector-Project Report - Download as PDF File .pdf), Text File .txt) or read online. The document contain's the basic circuit of a metal detector,data. Rahul Metal Detector Full Report - Download as PDF File .pdf), Text File .txt) or read Certificate that this project report “Metal Detector” is the Bonafide work of.
For use in an electronic circuit. Flag for inappropriate content. The term tickler coil usually refers to a feedback coil. This changing transmitted magnetic field causes electric currents to flow in metal targets. If the metal detector is set to reject unwanted targets then a target response will not be produced for those targets. It is fortunate this crowding takes place.:
A Beat-Frequency Oscillator BFO type metal detector has been chosen for this project because by far, the circuit produces the characteristics and metal detection range that is required. To assure that The metal detector circuit functions accurately, certain calibration and tuning has also been done on the circuit. Meanwhile the usage of Microchip PIC 16F microcontroller assure that the alarm system have the capabilities to operate efficiently.
This thesis report provides an introductory background on the Metal Detector technology and an introduction on the thesis objective and the products available in the market. It further elaborates the design and implementation of the product.
It reports the result of the product evaluation and makes recommendation for improvement. Finally, it concludes the thesis. Home, Office, Shopping Mall and other place can use our technology. We mostly look at the detection and the safety of places. Our project work like other security system but we do a reverse engineering on it.
But we do reverse design what is, the door all ways be open and when the detector detect any metal then the door will be close and give signal. By this way no innocent person will be herbage and the victim will get cot. It can update by many way as like taking picture wen detected and other way. Detection and clearance are still being very often carried out in Humanitarian Demining using manual methods as the primary procedure.
Metal detectors are still to the best of our knowledge, apart from dogs, the only detectors really being used in the field, and are probably going to remain in use for some time. Metal detectors cannot unfortunately differentiate a mine or UXO Unexploded Ordnance from metallic debris. In most battlefields, but not only there, the soil is contaminated by large quantities of shrapnel, metal scraps, cartridge cases, etc. Each alarm means a waste of time and induces a loss of concentration.
Note that when manual methods follow other procedures, such as mechanical clearance, constraints on the need to check each alarm are often somewhat relaxed. When looking at the actors dealing with metal detectors we are confronted on the one hand with a relatively small market in which mostly SMEs operate, on the other with a scientific community which is not always aware of the practical problems linked to the actual production of equipment and its operation under field conditions e.
Manufacturers do not tend to participate to scientific conferences and workshops, and rely mostly on patents, of which the scientific community is not always aware, to protect their intellectual property. To increase cross-fertilization opportunities interesting patents in fields other than humanitarian demining e.
A patent is a form of personal property that provides the owner with the exclusive right to make, use or sell the invention described in the claims of the patent, and is valid for a period of 20 years from the date of filing. Patents and published patent applications are public documents and not protected by copyright. Patents can be very helpful as starting point for a new invention or a further development; this is particularly true when there is otherwise a lack of information, as in the case of metal detectors.
The technical know-how is often explained in detail including diagrams, flowcharts and other useful graphical information; the description of the state of the art of the technology is also often quite useful. On the other hand patents are not scientific publications as commonly found in research papers for example; the reader has therefore to read quite often between the lines and cope with the typical jargon used in these documents.
COIL An electromagnetic coil or simply a "coil" is formed when a conductor usually an insulated solid copper wire is wound around a core or form to create an inductor or electromagnet. A transformer is an electromagnetic device that has a primary winding and a secondary winding that transfers energy from one electrical circuit to another by inductive coupling without moving parts.
Multilayer coils have the problem of interlayer capacitance. A completed coil assembly with taps is often called a winding. As self induction is larger for larger coil diameter the current in a thick wire tries to flow on the inside.
Coils are often coated with varnish or wrapped with insulating tape to provide additional insulation and secure them in place. When electricity is passed through a coil. One loop of wire is usually referred to as a turn.
Sometimes this means that a spiral is a better alternative. The coil tap s are points in a wire coil where a conductive patch has been exposed usually on a loop of wire that extends out of the main coil body.
A coil tap is a wiring feature found on some electrical transformers. For use in an electronic circuit. The term tickler coil usually refers to a feedback coil. WORKING Metal detectors work on the principle of transmitting a magnetic field and analyzing a return signal from the target and environment. The magnetic transmitter is in the form of a transmit coil with a varying electric current fl owing through it produced by transmit electronics.
This changing transmitted magnetic field causes electric currents to flow in metal targets. The receiver is in the form of a receive coil connected to receive and signal processing electronics.
The transmit coil and receive coil are sometimes the same coil.
The transmitted magnetic field varies in time. Transmit signal from the electronics causes transmit electrical current in transmit coil. These electric currents are called eddy currents. The regenerated magnetic field from the eddy currents causes an alternating voltage signal at the receive coil. This is amplified by the electronics because relatively deeply buried targets produce signals in the receive coil which can be millions of times weaker than the signal in the transmit coil.
In summary: It is the altered shape of this regenerated magnetic field that metal detectors use to detect metal targets. This field is altered compared to the transmitted field. As with most introductions. Electrical current in the transmit coil causes a transmitted magnetic field. Receive coil detects the magnetic field generated by eddy currents as a very small voltage. Signal from receive coil is amplified by receive electronics. Eddy currents generate a magnetic field. Because it is the same shape as the transmit field.
Both the target X and R signals vary depending on the distance of the target from the coil. Transmitted magnetic field causes electrical currents to flow in metal targets called eddy currents. The signal induced in the receive coil. These X and R signals magnitudes are further processed to give an output signal which may be reported to an operator in a number of different ways. The same applies to the R signal. For example. In metal detectors. A ground balanced audio signal.
Most discriminating metal detectors also have a visual display which indicates properties of a detected metal target.
These properties may be varied by a metal detector operator varying the controls of the metal detector. Applications 1. Metal detectorists may be dedicated to preserving historical artifacts. Their excavation and preservation is greatly facilitated due to metal detectors. Archaeology Many historic artifacts from post Paleolithic age are metallic.
These valuable items which generally include pots. Metal detecting is very similar to coin shooting except that the metal detectorist is after any type of historical artifact. Prospecting is looking for valuable metals like gold and silver in their natural forms. Serious coin shooters will spend hours. Hobbies Coin shooting is looking for coins after an event involving many people. Security screening In common with the developments in other uses of metal detectors both alternating current and pulse systems are used.
In systems such as the Metor appeared with the ability to indicate the approximate height of the metal object above the ground. Industrial metal detectors Industrial metal detectors are used in the pharmaceutical. The next technique is called "Random searching".
Many dedicated beach hunters also familiarize themselves with tide movements and beach erosion. Beach hunting can be as simple or as complicated as one wishes to make it. Contamination of food by metal shards from broken processing machinery during the manufacturing process is. There are two main techniques for beach hunting. Many Minelab detectors also provide a visual display of target information. The battery provides power to the detector. In this example. If the metal detector is set to reject unwanted targets then a target response will not be produced for those targets.
Transmit Electromagnetic Field: The transmit electromagnetic field energises targets to enable them to be detected. Concept Metal detectors work by transmitting an electromagnetic field from the search coil into the ground.
If this electromagnetic field were visible. The battery is the power supply. In the drawing at the bottom of the next page note the area indicated as the two dimensional detection patterns. Electromagnetic Field Generation As the current circulates in the transmitter antenna. Metal Detection is achieved. The block diagram on the facing page illustrates the basic components of a typical metal detector. Note theMirrorimage detection pattern above the search coil.
This electronic block diagram of a transmitter-receiver metal detector illustrates the basic components of a metal detector as they are pointed out in the description at left. It is fortunate this crowding takes place.: Electromagnetic field theory states that field lines cannot cross one another.
The transmitter signal current travels from the transmitter oscillator through a wire search coil cable. This is the site of maximum field crowding. The transmitter electronic oscillator at the extreme left of the diagram generates a signal.
On the other hand. The power or motivating force that causes eddy currents to flow comes from the electromagnetic field itself. Iron mineral detection is a major problem for both manufacturers and users of metal detectors. When this induced power is sensed by the detector circuits.
Electromagnetic Field Distortion The detection of non-conductive iron ferrous minerals takes place in a different manner. Of course. The portion of the secondary field that intersects the receiver winding.
Mirror-image pattern atop coil is not used. Whenever metal comes within the detection pattern. When iron mineral comes near and within the detection pattern. As transmitter current from the antenna generates the electromagnetic field. One detector design criterion requires the elimination of. When a target comes within the detection pattern. When any metal comes within the detection pattern of a search coil.
This inhibiting of the electromagnetic field. Coupling is inhibited. There is perfect coupling into some objects such as wood.
How this discrimination is accomplished depends on the type of detector. Even though modern instruments can eliminate the effects of iron minerals. Component list: For comparison. It can give milli watts output. Non-electrical loudspeakers were developed as accessories to telephone systems. Variable capacitance trimmer: A variable capacitor also known as a "variable air condenser" is a capacitor whose capacitance may be intentionally and repeatedly changed mechanically or electronically.
A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. A transistor is a semiconductor device used to amplify and switch electronic signals and power.
Because the controlled output power can be higher than the controlling input power. At the input there is a signal generator and at the output a RF voltmeter.
Stereo amplifier: A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. A capacitor originally known as condenser is a passive two-terminal electrical component used to store energy in an electric field.