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Abstract
The purpose of the Mattel Detector with Counter Using Metal Detector project is to demonstrate the use of a metal detector to detect any metal devices used by an intruder right before he has a chance to open the door or window. This will solve the problem with conventional sensors or detectors where the alarm only activates once the intruder has broken an entrance. To realize this project, extensive research and studies have been done on metal detector technology, 555 IC and the theory of Nicolai Tesla coil and also alarm circuit. 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 16F628 microcontroller assure that the alarm system have the capabilities to operate efficiently. The capabilities of the home alarm system is not only limited in detecting an intrusion attempt but also capable to perform certain features like set/resetting the alarm for a certain period of time, display the alarm status via LED, The alarm system alerting apparatus consist of siren, strobe light and buzzer. 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.
By SHANJEDUL
HASSAN
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Introduction Our project of metal detector is a security base project to use in every ware. 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. As like every metal detector work the condition as, when the detector didn’t find any metal in the way then the get will open. 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. When operating in this way the detection phase still relies heavily on metal detectors, whereby each alarm needs to be carefully checked until it has been fully understood and/or its source removed. This is normally done visually, and by prodding and/or excavating the ground. Metal detectors ar e 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., leading to between 100 and 1,000 false alarms for each real mine. 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.g. the importance of ground signals). 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.g. security applications or Non-Destructive Testing) have also been integrated whenever possible and appropriate.
By SHANJEDUL
HASSAN
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By SHANJEDUL
HASSAN
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General Patent Information and Structure: 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 applicati ons 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. The form of a patent looks similar in all states. The important parts like author names, dates, abstracts, etc. can easily be found in all kind of patents. Most of the patents listed in this report are of US origin and therefore we will focus on these to briefly describe their different parts. Categorization after the Importance
Furthermore the patents are divided in three categories according to their importance. Those that seem to represent the most important ones are marked bold with a star in front of the patent number. We call these patents Reference Patents. In this first category fall the patents with an absolutely new invention in the given field. The second category – the Important Patents – is also marked bold. These are also interesting patents because they include good explanatory text or illustrative drawings, etc. The third category includes all the other patents we found on a given topic and is not highlighted. The patents in the first and second category, i.e. the most important ones, are summarized so as to help the reader focus on their new and/or most important parts.
By SHANJEDUL
HASSAN
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Schematic view of the patent classes and subclasses used in this work
By SHANJEDUL
HASSAN
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TECHNOLOGY BASICS
Figure 1 shows a simplified diagram of the basic pulsed-EMI technique. A current loop transmitter is placed near the metal object, and a steady current flows in the transmitter for a sufficiently long time to allow turn-on transients in the object to dissipate. The loop current is then turned off. According to Faraday’s
law,
magnetic
field
the
collapsing
induces
an
electromotive force in the metal object.
This
force
causes
eddy
currents to flow in the metal. Because there is no energy to sustain the eddy currents, they begin to decrease with a
characteristic
decay
time
that
depends on the size, shape, and electrical and magnetic properties of the metal. The decay currents generate a secondary magnetic field, and the time rate-of-change of the fi eld is detected by a receiver coil located at the sensor. If a conductive object is shown to have a unique time-decay response, a signature library of conductive objects can be developed. When a concealed metal object is encountered, its time-decay signature can be compared to those in the library and, if a match is found, the object can potentially be classified. Classification allows discrimination between potential threat and no nthreat objects.
By SHANJEDUL
HASSAN
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Circuit Diagram
By SHANJEDUL
HASSAN
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HOW METAL DETECTORS WORK
By SHANJEDUL
HASSAN
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Illustration 'A' shows a typical metal detector user. He has followed the instructions supplied by the manufacturer and has his metal detector turned on. After testing his detector on some surface targets (coins) to make sure it is working, he now starts searching for buried coins and treasures. Notice the "red" signal pattern being transmitted from the search coil into the ground. (Note: we have enlarged the illustration of the signal pattern for easier understanding). As long as the signal entering the ground does NOT come in contact with metal, there will be no audio signal,
no
flashing
light,
no
vibration,
nothing
will
happen.
Illustration 'B' shows what happens when the detector user's metal detector search pattern
comes in contact with metal objects, in this case both shallow and deep coins. When the search pattern touches metal it interrupts the transmitted signal and this interruption or disturbance of the search pattern will cause the metal detector to alert the detector user (you) with an audio signal, usually a distinct loud sound. In some cases flashing or blinking lights will accompany the audio signal.
More Complete Explanation of How Metal Detectors Work How Metal Detectors Work Reprinted with permission from Modern Metal Detectors It is not necessary to understand the scientific principles of metal detection to use a detector. You can find coins, rings, jewelry, gold nuggets, caches or whatever you are searching for without knowing how your detector works. For better comprehension of that your detector is doing, however…to recognize why it just made that peculiar sound…to understand why it reacts the way it does to metals and minerals…it is necessary to learn how to a metal detector works. Two examples illustrate this need. First, let’s say you are scanning in the field and get a detector signal. You dig down a foot and find nothing. You enlarge the hole and dig another foot and still don’t find anything. You m ight keep on digging to five or six feet before finally giving up. Yet, your signal persisted throughout all this digging! What went wrong? Was it your fault, or that of your detector? Was a target there? Well, yes there was a target though it may not necessarily have been a metal one. The response could have been due to some variation in mineral content. For the second example, let’s say you are researching for a small kettle made of iron that is filled with gold coins.
By SHANJEDUL
HASSAN
