What is the principle of the treasure finder and what treasures can be found?
Generally speaking, the so-called treasure detector actually refers to metal detectors, such as underground gold or silver and bronzes, or copper coins, etc., all of which are metal objects, so it is worthy of the name to use metal detectors for treasure detectors!
The principle of metal detector is actually very simple. It uses the high frequency current in the metal coil, which is equivalent to a hollow coil that can generate a magnetic field. If a metal object appears in or near the hollow coil, these alternating magnetic fields will induce eddy currents on the metal, thus affecting the magnetic field in the hollow coil. At this time, monitoring the changes of these magnetic fields can sense whether there are metal objects nearby!
Although the principle is simple, it is also realistic, because the metal detector can indeed find metal, but remember that it is metal, not treasure, and most of the time you think you have found underground treasure. For example, in an ancient city that was demolished, you thought it might be a gold ingot or a silver ingot, or at worst it might be a silver coin, or you could find an ancient coin to make it up, but you dug up a lot of soil in a hurry and found that it was easy to roll decades ago.
Is there a detector that can distinguish underground metals?
Actually the answer is yes. The above is just the simplest principle. Any metal can give an alarm, even some mineralization reactions, so what can be done to distinguish between various metals? That starts with understanding the principle of metal detectors!
According to the detection principle, metal detectors can be divided into electromagnetic induction type, X-ray detection type and microwave detection type. Of course, X-rays are transmissive and need to be emitted at one end and received at the other, or have a reflective surface for X-rays. For example, when taking dental photography, it is necessary to set a reflecting surface behind the teeth. So common metal detectors generally refer to electromagnetic type. Here are two excellent metal detector principles:
Very low frequency metal detector, also known as inductive balanced metal detector.
This is the most popular metal detector at present. It has two coils, one is the transmitting outer loop and the other is the receiving inner loop. The receiver coil can be equipped with a filter circuit to filter out the interference magnetic field of the transmitter coil, but it will not induce the electromagnetic waves emitted by underground metal objects after the outer loop coil is launched. This kind of electromagnetic wave can be displayed on the display screen in the form of alarm or numerical characteristics of electromagnetic wave after being amplified by the inner ring receiving coil, and a depth can be roughly determined according to the numerical value.
VLF technology has a certain ability to identify the properties of metals, because different metals have different conductance and resistance values. VLF metal detector uses a pair of electronic circuits called phase demodulators to measure the phase shift and compare it with the average phase shift of known metals, so as to judge the properties of this metal!
Advanced metal detectors can even set an ignore interval, such as shielding a certain value and giving an alarm response only to a certain range of values, such as ignoring cans, nails and other items, but it is also possible to miss rings or nail-like items.
Metal detector based on pulse induction technology
It can use a single coil to complete the task of transmitting and receiving, or it can use the time-sharing mode of multiple coils to complete the task. It sends out a high-energy short-time pulse signal, and when there is a metal object underground, it will form an echo-like signal on the metal. The coil receives this signal between the launch and the next launch, so as to judge whether there is a metal object underground.
PI technology is not suitable for identifying metal objects, but according to the data, PI technology is better in detecting small pieces, and the performance of PI detector is better in heavily mineralized soil. PI technology can detect metals indiscriminately, and even can be used underwater, which is the advantage of PI detection technology!
Underground metal detector based on pulse principle
There are many treasure hunters in the market who claim to be able to distinguish various metals, but it is impossible to really distinguish metals accurately, and there will always be various false positives. The reason is that the underground environment is not complicated, which is by no means comparable to the simulated environment. Of course, the products that perform better in treasure hunting are definitely right, so it is definitely right to find the products with the highest sales volume in the world, such as the bounty hunter-Garrett 350, but the problem is that the price is tens of thousands, so you should think carefully before buying.
Handheld metal detector
In addition, the metal detector is not only a treasure hunt, but also a handheld product (BFO mode, low accuracy, suitable for non-contact body search), a metal detector with a fixed door, and even can screen metal particles in agricultural products or plastic products.
Baby is more than metal, such as porcelain. How to find it?
In addition to electromagnetic waves, ultrasonic waves can also penetrate the formation. For example, common artificial seismic waves are used to image large underground areas to detect underground structures. This method is widely used in oil exploration or coal and mineral mining. And this kind of large-scale and large-area imaging can reach square kilometers or even higher, and the depth can reach dozens of kilometers or even penetrate the earth (using the seismic waves of the earthquake)!
Of course, it can also be used to detect underground antiques, such as looking for gold jewelry and various porcelain bronzes. However, the main function of ultrasound is to image the underground in three dimensions. It can barely keep the accuracy of identifying whether metal rocks are open or not, but it is a bit reluctant to identify metal types. So the best way may be to scan with a metal detector and then use ultrasonic imaging. We can have a general understanding of the underground before excavation!
However, the price of an excellent ultrasound imaging is also a drop in the bucket. You can buy it back and try it, and then find a friend with a top metal detector. It's a perfect match, invincible. I wish you a fortune first!
Can you really find the treasure with these devices?
Of course, you can use metal detectors to find treasures, but even the top metal detectors have a high false positive rate, so although you can see reports in various news that the detectors have found ancient gold coins or other valuable jewelry objects, it is actually the deviation of survivors, because there are still a large number of friends who have bought treasure hunters, and they have silently contributed their tuition fees to the whole industry!
An American treasure hunter discovered the legendary Finnish treasure, cultural relics and jewels worth $2 million.
But I will never kill your dream of making money. Maybe the next news will happen to you. Of course, you can also get rich silently. As for why, I won't say much!
Further reading: Luoyang shovel
Friends who like to watch tomb raiders must know Luoyang shovel, which is an underground detection device in ancient China, but it is not used to locate gold and silver vessels, but to locate ancient tombs with geomantic omen, because the soil covered by ancient tombs varies widely. According to the different soil brought out by Luoyang shovel, the location of the ancient tomb can be accurately located!
Of course, don't think that Luoyang shovel is made by grave robbers. In fact, archaeologists also use Luoyang shovel, and the threshold for using Luoyang shovel is relatively low. So maybe, many friends have it at home, but it is illegal to rob a tomb. Don't challenge the law except for fun!