Full description of Terminator 3 metal detector. Making a Terminator metal detector with your own hands

Hello to all comrades, today we will try to figure out what kind of metal detector is the Terminator? Have you probably heard of such a device? In particular, one of the popular models is the third. A friend of mine, whom we met on the Internet thanks to our hobby, has a “Therma” and this is what he told me about this device.

There are plenty of photos on the Internet, all different modifications:

Regular three:

Terminator M model:

Well, and another photo of two homemade products at once:

The first and most important thing is that this is a homemade metal detector, which means that it is made by ordinary people, or rather by those who are well versed in circuits and electronics. If you are not good at this, then you won’t be able to do it yourself.

They make it according to schemes that are a dime a dozen on the Internet. The most important thing is that there are a lot of nuances here and each “developer” makes the device for himself - changes something, improves it, adapts it. Here is the general diagram - using it you are guaranteed to assemble this MD yourself:

And this is what the board looks like, where everything is already soldered:

“Therma” has several varieties - here we can talk about the “Trio” model, it has been improved, some gadgets have been added to make the search more convenient and comfortable. The Trio already has 2-tone identification and, compared to older models, it is more convenient for them to search.

The Terminator 4 model is already considered obsolete, but those who started with it speak warmly of this model and continue to use it. It was “invented” already in 2007, while the “troika” is already 2009.

Three and four are most often single-tone devices (however, now two-tone models have also begun to be assembled), but the “Trio” is already 2-tone. So if you decide to buy a “thermal”, then it’s better to take a two-tone model. Still, when there is no display that helps in digging, and you have to navigate only by sound, then the more tones, the better. And here, single-tone homemade products, of course, lose out to factory devices, which have several tones by default.

There are also PRO models and a recent new product - 2012. We won’t talk about them here for now, because in price they are already comparable to professional-level devices.

Which is better, Terminator or Garrett Ace 250?

As you can see, this MD is practically in the same price category; the third “term” on thematic forums can be bought for 4-5 thousand rubles. Whereas 250 ICQ costs at least 2 times more.

However, at such a low price in terms of depth, “Thermal” makes Asya, it sees colored targets deeper. Of course, if everything is configured correctly and the operator fumbles.

On the other hand, ICQ’s convenience and information content are an order of magnitude higher, and if you are a complete newbie to coping, then I would advise you to take a factory device. And ICQ is still time-tested - a worthy entry-level device.

Does this MD have a pinpointer?

A pressing question, because now they have become more alert to installing DD coils on them, and without a pin they have to dig huge holes, and even the search technology, when you cross a target, does not help. The answer is that there is no pinpointer, and therefore we recommend purchasing an inexpensive manual pinpointer from this list.

How well does he see small targets?

The design of this MD is such that it sees “small things” just fine and easily copes with all entry-level devices - graters and ICQ. Again, let us remind you that it will be difficult to master this device from the very beginning.

What is this metal detector for - for coins or for war?

Here the answer suggests itself - most often this model is discussed on forums dedicated to war cops (in particular, Reibert), and therefore they use it for this purpose. They dig for shell casings, helmets, rifle bolts and other things of interest to war seekers. However, antiquity diggers who use these devices place it above the ICQ 250 and 34 Minelab graters, primarily in terms of detection depth.

Which MDs are “Terminator” most often compared to?

Most often they are compared with devices of the same level - in particular with the Cardinal Profi MD from the Sturmlab office. However, as diggers note, “Thermal” is more balanced, there are fewer glitches (Cardinal often starts if you wave the reel on dewy grass). Well, I also note that the food lasts longer.

In general, after talking with the comrade, I got the impression that the device is actually very worthy, well, it’s not for nothing that it has so many fans and admirers. Plus they are actively improving it, adding more and more new features.

And now I’ve already seen quite “sophisticated” metal detectors with convenient panel and nice design. And in terms of characteristics, they say that they compete even with Minelab’s mid-range and top-end detectors - 705 grater and Exp. So this MD is worth paying attention to. Well, if you are comfortable with a soldering iron and are tinkering with all sorts of circuits and transistors, then maybe you should try assembling it yourself? Fortunately, the Internet is full of schemes, and there are many thematic forums.

And finally, a video of a cop with Therm-4 - the quality is so-so, but what discoveries and most importantly - a new, lyrical song about diggers. I advise you to watch it even purely because of it. Well, you can clearly see that with this MD it is quite possible to dig for ancient coins.

One gets the feeling that there are simply no other signals, only coin ones) And there are no false ones either, which indicates good settling from the ground and general setup device.

But here’s a test video about the “Trio” model - it’s more fun and understandable:

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Specifications:
-The principle of operation is induction balanced
-Operating frequency, kHz 8-10kHz
-Dynamic operating mode
-Precise detection mode (Pin-Point) no
-Food, 9-12
-There is a sensitivity level regulator
-There is a threshold tone control
-Ground adjustment is available (manual)

Detection depth by air
-coins 25mm - about 35cm
-gold ring - 30cm
-helmet 100-120cm
-maximum depth 150cm
-Consumption current:
-Without sound approximately 35 mA

Brief instructions
The device is single-tone - this is both a plus and a minus at the same time. It’s a plus because if a clear signal appears in both directions of the wiring above the target, it means there is 90% non-ferrous metal under the sensor. The downside is that there is one tone for all non-ferrous metals. Sometimes the device may mistakenly identify a flat piece of iron (for example, a piece of roofing or a tin can) and pass it off as non-ferrous metal, but with little experience in using the device, such errors are easily distinguishable. The fact is that if there is an error on the hardware, the device will either produce an unstable, ragged signal, or the signal will be stable, but only in one direction of the wiring. The device simply does not produce a signal for ordinary pieces of hardware. A small but very useful trick when searching, if you suddenly doubt whether the metal under the sensor is ferrous or non-ferrous, that is, if the device produces an incomprehensible signal, then you need to switch to the “all metals” mode, if the signal has become clear in both directions of the sensor wiring above the target - This means that there is definitely ferrous metal underneath, but if the signal has not changed, it means that there is definitely non-ferrous metal underneath the sensor. Of course, you need to get used to the device and understand how it works. Although getting used to it happens quite quickly. In two or three outputs you will already be able to almost accurately determine target type.
Powered by a 9V KRONA battery (batteries are not recommended). You can use an 8.4V CAMELION battery.
There is no need to write about turning it on and off, everything is already clear with this. So
Adjustment:
1) Ground balance (GB) - the detuning from the ground is very sharp, you can easily cut off copper along with the ground. Therefore, when detuning from the ground, the handle must be turned carefully (little by little). This is done like this: For example, you went out into the field, turned on the device, lifted the sensor from the ground and lowered it to the ground - if a signal was heard on the ground, then turn the B\G knob slightly counterclockwise and repeat raising and lowering the sensor. This is done until the ground signal disappears. As already written, you cannot twist the BG, otherwise the copper will be cut off. For a better reference, it is advisable to make a mark on the body of the device in which position of the handle and the ground is cut off and the copper is clearly visible.
2) Discriminator for cutting off unwanted targets - when turned counterclockwise, it cuts out metals in turn from cigarette foil to brass. Only the copper remains uncut.
3) Sensitivity knobs. There are two of them, one is a coarse setting, the other is a smooth adjustment. The smooth adjustment knob is set to the middle of the revolution, and the coarse feeling adjustment knob is turned until small (very short) false beeps appear and is moved back slightly. After this, using the smooth adjustment knob, the sensitivity is adjusted so that there are no false alarms and the sensitivity is at the same level. The device itself is very sensitive, so you should not abuse the sensitivity adjustment. Again, to avoid false positives.
4) Switch for “color only” and “all metals” modes – switches these modes. In the “all metals” mode, the device reacts to all metals, and the detection depth increases slightly.
5) Beach mode switch “gold only” – switches the device to this mode and works only when the other switch is in the “color only” mode. In the “gold only” mode, the device gives a signal only to gold, to aluminum caps with rings (such as TUBORG), to silver, to aluminum pull tabs from beer cans and to modern white goods (except for five-ruble coins). It can also give a signal to strong a rusty beer cap, but this is rare.
6) Sensor cable - it must be wrapped around the device rod and secured tightly in two or three places either with self-tightening plastic clamps (usually sold in car dealerships) or simply with electrical tape in order to prevent the cable from moving during the search. The fact is that the device does not provide a buffer to exclude false alarms from cable movement (many purchased devices, by the way, also do not install this buffer since it reduces the target detection depth). Well, that seems to be all. Happy Findings!

Fig 1. Device diagram.

P.S. The archive contains all the information necessary for assembly. This device was assembled by me personally, works great!!!

A proprietary device, known as the Terminator 3 metal detector, is used for targeted searches for coins of various denominations. The circuit solutions used in the device ensure the extreme sensitivity of inductive sensors, allowing you to identify metal objects with a high degree of accuracy.

Design and principle of operation

Metal detectors under this name are assembled according to the classical scheme, in which there are two inductive coils (transmitting and receiving), as well as an additional winding called compensation.

The transmitting coil is connected directly to a self-oscillator that produces a pulse signal relative to high frequency. As a result, it begins to emit electromagnetic oscillations (waves), creating an alternating field in the search area. Propagating in the medium under study, this field, in turn, induces voltage fluctuations of similar shape in all metal objects.

Note! The field created by the transmitting coil affects the receiving circuit of the metal detector itself and also induces small amplitude oscillations in it.

In the absence of foreign metal objects, the potentials acting in both coils are balanced by means of an additional compensation winding. When any metal object appears in the area under study, the established balance is disrupted. In this case, the sensitive element electronic circuit amplifies the difference signal and directs it to the actuator, which generates warning pulses.

Based on the described operating principle, the MD Terminator 3 device includes the following electronic components:

• Generator of a pulse signal that creates a local electromagnetic field;
• “Catcher” or receiver having the required sensitivity;
• Compensation scheme;
• Differential amplifier with detector;
• Executive device.

The device is designed as a structural module with an external probe frame into which the measuring coil itself is built. The main part of the electronic circuit is located in a separate console containing a power source, as well as indication and sound notification elements.

The procedure for handling the device can be found in the instructions supplied with it.

Technical description

The mode of measurements carried out by the device with the excitation of an alternating electromagnetic field is classified as IB (induction balance). The metal detector has the following technical indicators:

• Operating frequency – 7-20 kHz (the exact value is set by changing the ratings of the master capacitors);
• Ability to select the appropriate search mode for metal products (“Discrimination” and “All metals”);
• Manual balancing “Soil index”.

To the specified operational capabilities should be added the presence of autonomous power supply, supplied from a 9 or 12 volt battery.

The detection depth of coins in the soil (with a working coil with a diameter of 240 mm) is:

• 5-ruble coin (Russia) – 22-24 cm;
• 5 kopecks (from the time of Catherine II) - about 30 cm;
• wartime steel helmet – up to 80 cm.

For a more complete understanding of the principle of detecting coins, it is advisable to familiarize yourself in as much detail as possible with the VDI scale for this model, which is valid in the “Discrimination” mode and facilitates their identification.

Advantages and disadvantages

The advantages of the product in question include the ability to clearly identify objects made of non-ferrous metals (with a probability of 85%). The remaining part (15%) consists of cases of detection of iron or heavily rusted objects.

Additional Information. Devices of this class differ significantly from some of their analogues (Terminator 4, for example), which are capable of determining only the depth of an object.

The list of their advantages can be supplemented with a low relative measurement error.

In various situations, such detectors make it possible to detect objects at depths not exceeding the size of a shovel bayonet, which is not bad at all for this class of devices. In all other respects, the model in question is considered a fairly “powerful” device, superior in its capabilities to its known analogues.

Their disadvantages, in addition to their relative high cost, include low sensitivity to rust-affected iron. In some cases, when an erroneous “dirty” signal is issued, indicating something between black and non-ferrous scrap (or vice versa), metal covered with a layer of rust is detected. You can learn to distinguish a false signal from a useful one only after a long period of mastering the techniques of working with this device.

Self-production

Preparation and assembly

In order to make and test a metal detector with your own hands, first of all, you need to assemble its electronic part, and then place the individual boards in a suitable housing. As an example, consider the device diagram given below in the text.

Important! To assemble boards yourself, you need to be able to handle a soldering iron professionally and have basic skills in soldering microcircuits.

All radio-electronic elements indicated in the diagram, after their acquisition, are soldered into a printed circuit board, which is placed in the housing (its general view is given below).

After the circuit is assembled, you can proceed to visually checking the quality of soldering of the printed circuit board. But first, it is thoroughly wiped with a clean flannel soaked in solvent, which allows you to clean the connecting tracks and contacts from any remaining traces of flux.

Settings

After assembling and connecting the individual components, we proceed to setting up each of the device modules, which will require the following measuring equipment:

• Single-channel oscilloscope of any type;
• Modern multimeter with a full range of functions;
• Universal generator or “LC meter”;
• Electronic frequency meter.

When setting up the assembled device using an oscilloscope, the presence of a radiating signal and the absence of voltage at the amplifier input in rest mode are checked.

The required frequency of the emitted signal is set using a frequency meter by changing the output capacitance oscillatory circuit. Using the same oscilloscope, the presence of a useful signal at the input of the amplifier and the output of the detector is checked in measurement mode.

Functionality check

The test begins with the sensitivity control knob of the device being turned to the maximum so that a stable sound signal is heard in the speaker.

After this, you should touch the frame with the inductive sensor with your hand and monitor the change in sound. If it is immediately interrupted, this means that everything was done correctly and the circuit is working properly. Otherwise, you should check the entire circuit, stage by stage, using the same oscilloscope.

Note! The control LED should blink after being supplied to the power circuit and immediately go out. When the voltage is removed, it lights up and then gradually fades out.

In conclusion, we note that the final configuration of the device is carried out at the place of its use (taking into account the soil in the possible search area). To be completely confident in the performance of the device, it is recommended to test it on various samples of metal parts.

Video

For those who do not want to spend money on a branded device, I suggest assembling a Terminator 3 metal detector.

The search characteristics of this device can compete on the same level with purchased brands costing under $200. Terminator circuit solutions are almost the same as in branded devices of the TESORO line, but easier to configure and manufacture.

The device showed its best performance, discrimination on high level, low current consumption of the device, low cost and availability of parts, as well as the ability to work on heavy soils. The device board has been tested and works great.

Specifications:

Operating principle: induction balanced

Operating frequency, kHz 7-14 kHz

Operating mode dynamic

Power, V 9-12

There is a sensitivity level regulator

There is a threshold tone control

Ground balancing is manual.

Detection depth by air with DD-250mm sensor

Coins 25mm - about 30-35 cm

Gold ring - 30cm

Helmet 100-120cm

Maximum depth 150cm

Consumption current:

No sound approximately 35 ma

Metal detector diagram:

Board in .lay format:

We transfer the tracks onto the textolite using LUT (Laser Ironing Technology).

We poison the board, for example, in ferric chloride.

We tin the paths and drill holes for the parts.

We start the assembly by soldering in 16 jumpers, then carefully solder in the SMD resistors, then the sockets for the microcircuits and everything else.

It is better to take a multi-turn variable resistor threshold regulator (the setting is more comfortable), but you can get by with a regular one, in this case you need to turn it more carefully.

The board is ready to be inserted into the case. The MC10 chip and its harness do not need to be installed; this is a low battery indicator.

A small recommendation regarding the manufacture of the device board. It is advisable to have a tester that can measure the capacitance of capacitors. The device has two identical amplification channels, so the amplification through them should be as identical as possible; for this, it is advisable to select those parts that are repeated at each amplification stage so that they have the most identical parameters as measured by the tester (that is, what readings in specific cascade on one channel - the same readings on the same cascade and in another channel), and it is also advisable to select circuit capacitors C1 and C2 with the same readings on the tester, this will greatly facilitate your setup of the device.

Making a coil

The DD sensor is manufactured according to the same principle as for all balances..

TX is the transmitting coil and RX is the receiving coil. Number of turns - 30 turns with wire folded in half, wire diameter: 0.4 enameled winding. Both the transmitting and receiving coils are wound with a double wire (that is, there should be 4 ends of the wire), we determine the arms of the windings with a tester and connect the beginning of one arm to the end of the other, the middle output of the coil is obtained. The middle TX pin is connected to the minus of the board (without this the generator will not start), the middle RX pin is needed only for frequency tuning, after tuning the frequency (resonance) it is isolated and the receiving coil turns into a regular one (without output).

The receiving unit for tuning is connected instead of the transmitting one and is tuned 100Hz-150Hz below the transmitting one. The balance is achieved by shifting the coils (as on wedding rings) relative to each other. The balance should be within 20-30mV, but not higher than 100mV. After winding, the coils are tightly wrapped with thread and impregnated with varnish. After drying, wrap tightly with electrical tape around the entire circumference. The top is shielded with foil; between the end and the beginning of the foil there should be a gap of 1 cm not covered by it, in order to avoid a short-circuited turn. Each of the coils is adjusted in frequency separately; there should be no metal objects nearby.

I didn’t bother too much with the body :))

On the signet, instead of C1.1 and C1.2 (TX circuit capacitors), only one capacitor (C1) is placed, the frequency at which the entire device will operate will depend on its capacity, so it is not necessary to be tied to exactly the capacitor value indicated on scheme. For example, we set C1 on TX with a capacity of 100 nf, and set C2 on RX to 100 nf + 3.3 nf, and at the same time I get an operating frequency of the device of 10.5 KHz. You can also set other values ​​(that is, increase or decrease the frequency of the device, within reasonable limits, of course). The device can operate from 7KHz to 20KHz. The lower the frequency, the deeper it will take the target, but the discrimination will be worse for some targets, and vice versa, the higher the frequency, the shallower the depth, but the better the discrimination for some targets (such as gold, for example).

To assemble the board correctly, start by checking the correct power supply to all components. Take the circuit and the tester, turn on the power on the board, and, checking the circuit, go through the tester at all points on the nodes where power should be supplied. Where there should be 4 volts, then there should be 4 volts (well, plus/minus a few millivolts), and so on at all points. The second point: - The same applies to checking the assembly, turn the sense knob to the maximum and turn on the power of the board - the speaker should produce a continuous sound, when you twist the sense knob towards a decrease, the sound should disappear. If so, then the board is assembled correctly.

Next, we set all the knobs to zero (that is: the B\G knob - the ferrite is not cut out, and the discriminator knob - not a single color is cut out, the switch is in the "color only" mode), set C5 to start with 4n7, passed the ferrite over the coil ( if there is a double beep, then everything is fine, if a single beep, it means the ends have been switched to the TX in places), connect the oscillation probe to output C5 and move the coils to achieve a minimum amplitude.

So the device works, on which TX or RX coil should you solder additional capacitors when setting the reaction to metals? If ferrite is visible throughout the entire R8 range, then on RX; if ferrite is not visible throughout the entire R8 range, then on TX. Chocolate foil is at one end of the scale, copper is at the other end. This is what you should be guided by.

Here is the entire VDI scale as a guide, with the discriminator knob positioned at minimum, the device should see all non-ferrous metals, when screwing the discriminator, all metals should be cut out in order up to copper, copper should not be cut out, if the device works like this, it means it is configured correctly.

In this article I would like to post a diagram of a metal detector called Terminator-3. It has proven itself both by frequent assembly by radio amateurs and good characteristics search for what is discussed further in the continuation. The design of this metal detector, developed by Yatogan (Yatogan, MD4U forum) and Radiogubitel (MD4U forum), has circuitry similar to devices from the famous Tesoro company, but is much easier to set up. The impetus for the spread of this development was printed circuit boards(with modifications and improvements) by another homemade person - A2111105 (MD4U forum, Soldering Iron forum).

Metal detector characteristics:
detection depth - 5 rubles Russia - 22-24cm;
Catherine's nickel - 27-30cm;
helmet - about 80cm;
beer can under - 1 meter.

The detection depth is given for medium-mineralized soil (chernozem) with a sensor with a diameter of 240 mm along the wire. I want to say a little about discrimination: if in other devices of this class there is a certain discrimination threshold when detecting a target (i.e. the device sees an object at the maximum detection depth, but cannot recognize the type of metal from which the object is made), then in the Terminator this is a drawback practically absent - the device recognizes most objects at the maximum detection depth.

I’ll make a reservation right away - assembling and setting up this IB device will be almost impossible for users who are just starting their journey in mastering radio electronics, and even experienced electronics engineers can make mistakes. What, scared? But not everything is so sad - you just need to prepare properly and not rush. And the forum will help you with this.

Firstly, to assemble and set up the device, we will need instruments such as a multimeter, an oscilloscope, an LC meter (to select elements with identical characteristics for both channels of the metal detector), and we may also need a generator and a frequency meter. Of course, such a set of instruments costs a lot of money, and not every do-it-yourselfer is able to purchase it, but you can try to create a virtual measuring complex based on personal computer. Luckily there are plenty on the Internet. useful programs for these purposes.

Device diagram: in the “document” at the bottom of the material

Terminator3 is a single-tone metal detector based on the IB principle. Simple as three kopecks and reliable as a bulldozer. This is a pure coin machine with a simple modification that allows you to search for gold on the beach while ignoring most colored debris. Although the T3 is a coin machine, it can also be used for searching through the war and for collecting scrap metal. But for this it is necessary to introduce the “all metals” mode into the circuit (which is provided on the circuit and on the board); initially the circuit was without this mode.

The circuit is made with non-standard use of logic as an op-amp. The downside is that the KU of the mikruhs themselves is unknown (therefore, to average the parameters of the mikruhs, the cascades are parallelized), and the noise level is higher. It is possible to use domestic logic in this circuit, but it is not necessary, since the spread of parameters will be even greater. The only thing is that you can replace the sound generator with a domestic chip without damage. I would also like to add that in terms of depth and accuracy of target identification (color/non-color), the Terminator 3 metal detector is on par with branded brands in the mid-price category, and is head and shoulders above inexpensive branded MDs. This is not only my personal observation, but the general opinion of quite a large number of people who have used it. Of course, for this to happen, you need to assemble and configure it as expected, and not as you have to.

Detailed description of setting up the Terminator3 metal detector. Firstly, you need to look at the diagram where the nodes are indicated, so we will be guided by the nodes, in the future this will be useful for configuration. So, a self-oscillator produces current fluctuations when you connect a transmitting coil (hereinafter referred to as TX) to it. These vibrations come out of the MC1 chip in the form of a meander (like rectangular patterns on ancient Greek temples and amphorae). Now the receiving coil (hereinafter RX), it also has a current induced by TX (which creates a field) and it must be balanced with TX by this current (field) (that is, subtract the RX field from the TX field), and for this we need a compensation coil (hereinafter referred to as CX). In the DD sensor, CX is virtual, in the “RING” sensor it is real in the form of a coil. Here we connect it so that the current in it runs in the opposite direction in relation to RX (I will explain how to determine this later, when at least one of them is soldered by someone board) and by gradually unwinding the turns from it, we balance the TX and RX in current (this is called zeroing, balance, in other words).

We control the balance using an oscilloscope, achieving the minimum amplitude in all positions of the v/division knob in turn. When we reach the point when the amplitude begins to grow again, the tuning loop comes into play (it is made from one of the ends of the CX). But before that, we must adjust TX and RX in frequency, while making RX 100 Hz lower than TX (this will be the starting point point for further adjustment of the “window” of the metal scale). The coils, one at a time, are connected to the device generator and oscilloscope and tuned to the desired frequency.

CX does not need to be adjusted by frequency. What we get is that when there is a metal object under the sensor, the balance is upset (in one direction or another, depending on the metal), and a current begins to flow into RX, which from it enters the pre-amplifier, where it is amplified and fed to the synchro detector (see diagram) , and the synchro detector (SD) detects the phases of the incoming signal and outputs all this to the amplification channels, in the channels this matter is amplified and goes to the MC8 comporator, the comporator’s task is to compare the signal levels in the channels and if they match, the comparator gives permission to operate the sound generator. In general, this is how all balance beams work with minor differences; the differences relate mainly to the methods of ground detuning. In the Terminator, phase detuning (cutting, in other words).

Checking the metal detector board after soldering: Turn on the power on the freshly made and thoroughly washed board from flux, do not connect the sensor, unscrew the sense knob until a constant beep appears from the speaker, touch the sensor connector with your finger - the sound should stop for a second. If this is the case, then everything is in order and the board is soldered correctly and without jambs. When the power is turned on, the diode should blink and go out; when the power is turned off, the diode lights up and goes out slowly. Looking ahead: Indication of a low battery looks like this: the device begins to emit frequent signals with the same period of time, the diode is constantly on, and the sensitivity drops sharply.

Frequency tuning. All settings are made with the cable with which the device will continue to work. You cannot change its length after setting it. If you have experience in making sensors for a balancer, then it will be easier for you.