Do-it-yourself lie detector attachment for your computer. How to make an electromagnetic radiation detector with your own hands. Do-it-yourself diagrams for assembling various types of finders

Back in the 19th century, scientists proved that deception and denial of guilt cause a number of physiological changes in the human condition. The first thing that scientists noticed was high blood pressure, sweating on the skin, dry mouth, heavy inhalation and exhalation. Based on these phenomena, scientists, psychologists and physiologists developed a polygraph. Current lie detectors can determine whether a person answered the truth in more than 90% of cases.

The polygraph includes several measuring instruments with recording devices connected to them:

• sensor on an elastic bracelet, which is attached above the elbow, and gives readings about changes in pulse and pressure
• sensor, which is placed at the same level with the chest, to transmit the breathing rhythm to paper
• 2 sensors will be placed on the hands to record changes in the skin resistance of the test subject.

Testing is carried out as follows: a person is asked a series of questions, he must give answers to them yes or no. To begin with, they ask light questions that are not related to the incident in order to see what a person’s normal reaction is, then they ask questions that are directly related to the incident. And immediately a deviation from the norm is observed. This is shown in Figure 1.

For a more accurate test of the subject, there is a method with any cards. The test taker is shown 10 cards, of which he must remember only one. Then they are shuffled, and he must answer “no” ten times. It turns out that one time he will still lie. This answer will be recorded and used in a further survey.

In the United States, more than twenty national institutions (this also includes the police, FBI) ​​have had more than 500 lie detectors since 1965. Most private institutions, such as a bank, regularly test their employees with a polygraph. Companies that manufacture lie detectors conduct training courses for subordinates who then work with the lie detector.

How to make a lie detector at home

If you decide to try yourself as a polygraph examiner, but for now you do not want to buy a lie detector for several thousand dollars. You can purchase it from us, our company sells not only new but also used polygraphs at a price several times cheaper than new ones. You can also try to create it at home. However, basic knowledge of radio electronics is required.

Figure 2 shows a simplified electrical circuit diagram. However, it has high sensitivity, which means that if the test shooter is slightly agitated, the device will deviate.

Figure 3 shows two electrodes, they look like two loops, and are attached to the wrist or arm. When attached to the hand, significant sensitivity will be provided, but there will also be interference.

The sensitivity of the lie detector shown in Figure 2 is changed by resistor R1. A recorder can be connected to the output terminals. All resistors that are in the circuit serve only to protect the transistors from overloads. In the end you will get a good device with which you can do some very fun experiments.

Do-it-yourself polygraph, diagram two

The operating principle of this circuit is as follows: the device amplifies infra-low frequencies, the gain is 399-1199. What exactly the device will do depends on the type of output controller that will capture the output signal. You and I will use it as a “lie detector.”

As described above, thought processes are consistent with physiological changes in state. When a person is worried, the heart rate increases, and the frequency of inhalation and exhalation changes noticeably. It is very clearly possible to register how the resistance of the test subject’s skin changes; after several questions about what he wanted to hide, the resistance changes by 3-5%. To do this, we need two sensors that will be placed on the fingers of one hand of the person being tested. This is shown in Figure 2.

After we have attached the sensors to our fingers and turned on the device, we need to wait about 10 seconds for the transient processes to end. The person being tested should place his hands comfortably and not move them. Next, we ask questions to the examiner, and it is necessary to ask them not quickly, take a break for up to 4 seconds, and after the indicator lights have gone out. In some cases, the LEDs flash after each question, which symbolizes the person’s excitement. We need to give him time to calm down. As an example of test questions, you can use the method described above with cards. Figure three shows a single-sided printed circuit board for a homemade lie detector. The device contains radioelements:

• power from the crown;
• capacitors C1, C5, C6 are ceramic, and the rest are K50-6;
• transistor KT315; and ET361;
• resistors SP3-1B;
• two AL307 LEDs.

When starting a renovation or just needing to hang a picture, mirror or carpet, the problem arises with finding hidden electrical wiring that can be accidentally touched when driving a nail or screwing in self-tapping screws. Therefore, it is necessary to have a hidden wiring detector that will help you find all the wires in an apartment or private house hidden under the plaster. If you don’t have it, you can do it yourself.

Why are hidden wiring detectors needed?

Very often, owners of apartments or private houses do not have a wiring diagram, which is necessary when carrying out various repair work. While drilling holes or tapping, you may accidentally touch high voltage wires.

Remember! Regardless of whether you know where the electrical wiring is or not, all work must be carried out only when the power is turned off.

If you did the renovations yourself and know where the electrical wires are, this will greatly simplify the work process. But the fact is that wiring is often done by craftsmen who, trying to save money, lay the wires along the simplest path - from the distribution boxes not at right angles as expected, but diagonally. And in this case, you cannot do without a special device that allows you to quickly and accurately find hidden wires - hidden wiring detectors.

Such a detector can be purchased at radio stores or markets. They are inexpensive (budget models) and expensive. The cheap device helps identify live wires and various electrical appliances. More expensive devices are multifunctional and therefore can detect dead wires.

For home use, you can buy the simplest detector or assemble it yourself according to the diagram. Every person who understands electrical circuits can independently make an inexpensive budget device.

Types of modern search devices and their characteristics

Today there are a large number of detectors of various types. Some devices help to find not only wires in the wall, but also accidental breaks.

Based on the principle of their action, the following types of seekers are distinguished:

• Electrostatic.
• Electromagnetic.
• Combined.

Electrostatic testers

Electrostatic detectors help detect electromagnetic fields that come from live wires. These are simple finders that you can make yourself according to a certain pattern.

Features and characteristics of detectors:

• Since the finder responds to certain electromagnetic fields, the wires in the wall must be at high voltage to be detected.
• When working with the device, it is necessary to select a certain sensitivity level, since if it is too low, problems may arise with detecting wires that are too deep in the wall under the plaster. If the level is too high, the device may trigger erroneously.
• If the walls in the room are damp or there are many different metal structures in them, then searching for wiring will be almost impossible.

But given the low cost, ease of use and efficiency, such devices are used even by specialist electricians.

Electrostatic device for finding hidden electrical wiring

Electromagnetic devices

Such devices help to find electromagnetic excitation that comes from wiring connected to a specific load. The quality of work and accuracy of such finders is much higher than previous ones.

Also, these devices have one operating feature. In order to determine where a certain wiring is laid in the wall and how deep, it must have a load of at least 1 kW. For example, you can simply connect an electric kettle or iron to the mains.

Electromagnetic device for finding hidden wiring

Metal detectors (finders)

There are situations when it is impossible to connect voltage to the wires or load, then in this case metal detectors or finders are used. The devices work in this way: various metal elements enter the electromagnetic field of the finder, which cause certain vibrations that are captured by the detector.

Such devices clearly respond to any metal objects located in the walls, so in addition to wires, they will also find them.

Metal detector for finding wires in walls

Combination devices

Detectors of this type are multifunctional, as they are able to combine several types of devices that detect wiring in walls. Such functions significantly expand the range of use of detectors and increase their efficiency.

The TS-75 model, which contains a metal detector and an electrostatic finder, is in great demand.

Combined multifunctional device for finding hidden wiring

Homemade detectors can be:

• With sound indication. During operation of such a device, when it finds hidden wires, a characteristic sound is produced.
• With sound and light warning system (indication). When the device finds wiring, it not only emits a sound alert, but also the light begins to blink.
• On a field effect transistor. This device is easy to make according to a certain scheme. There are several different options for assembling a device with a warning light.
• Search alarm without batteries. The device operates from the mains, which also signals detection with a bright light located on the finder body.
• Detector on a microcontroller. Such a detector works on the responsiveness of the finder to the electromagnetic field, which is formed by the current flowing through the wires. During assembly, you can use an LED or a piezo sound emitter as a siren.
• Two-element device. The detector has an LED lamp as an indicator, which begins to glow when wiring is detected.

Examples and comparison of popular models

Currently, there are such a large number of different brands and models of devices for searching for hidden or broken wiring that it is difficult to consider everything and describe their characteristics, advantages and disadvantages. Therefore, we will consider only the most popular detectors that are used in home use.

• Electronic tester No. 48M is a multifunctional device for home use, which is used to check the integrity of wires, as well as to locate hidden wiring in the wall using contact and non-contact methods. It has LED indication and can detect wires that are located at a depth of up to 2 cm in the wall.
• The “Sparta” device for searching wiring and metal elements has a sound and light alarm. Allows you to detect not only wires, but also various metal elements. Finds breaks in the circuit.

  Device for finding hidden electrical wiring "Sparta"

• “Search” is used not only to accurately detect wiring in walls and ceilings, but also allows you to check the correct phasing of electric meters, identify equipment with a grounding or grounding break, check the serviceability of fuses, and determine breaks in wiring. Equipped with four sensitivity ranges.

  Hidden wiring detector "Search"

• Finder "Woodpecker M" E121.3 helps to find hidden wiring, check the correct phasing of meters, detect phase wires on various parts of the surface of the room, etc. It has a plastic case with a limiting rib for safe operation and four degrees of sensitivity.

  Hidden wiring detector "Woodpecker M"

• A small non-contact detector UNI-T UT12A made in China allows you to determine voltages from 90 to 1000 V AC. It has a light and sound indicator, as well as an automatic shutdown system after 30 minutes of inactivity. Outwardly similar to a regular marker. Very convenient for home use.

  Hidden wiring detector made in China

• The TS-75 wiring finder in a convenient metal case allows you to accurately determine the location of live wiring in a wall. Has light and sound indication.

  Multifunctional detector for detecting hidden wiring

• The inexpensive American-made S100 STANLEY STHTO-77403 detector is perfect for home and even professional use. Allows you to find not only hidden wiring, but also break points in the circuit. It has small dimensions and a convenient durable plastic case.

  American-made detector "STANLEY"

If we talk about domestically produced detectors, they are perfect for use for domestic purposes. They have affordable prices and can offer good quality. Chinese models are more compact and easy to use. They also have a low cost, but, as we know, this manufacturer cannot boast of a long service life of its products. By choosing brands from well-known European or American manufacturers, you can be sure that the detector will last a long time and will have the necessary amount of functionality for both home use and professional work at an affordable price.

Today, the choice of factory detectors is quite extensive, but some people often get “lost” in such a variety of devices. Therefore, before buying such a device, experts recommend clearly deciding what it is needed for - for single use or for constant work with hidden electrical wiring. Experienced craftsmen usually choose multifunctional devices that can recognize hidden metal elements of various characteristics.

Device for finding hidden electrical wiring for BOSCH brand professionals

When choosing a detector, you need to pay attention to the depth of its scanning. If the device is designed for a shallower depth, then during operation you can pass a wire located at a much greater distance from the wall surface being scanned.

Professional detectors can operate over long distances. Usually, household devices are purchased for home use, which are quite suitable for the walls of apartments, private houses and thin partitions.

Budget options that allow you to find only live wiring are much inferior in efficiency to expensive models, but they will help save a person from burns during work.

Do-it-yourself diagrams for assembling various types of finders

Let's look at the simplest circuits that you can assemble yourself if you have all the necessary devices.

Circuit with audio diode indication

You can make such a device yourself using resistor R1, which protects the circuit from direct induced voltage.

Diagram of devices for locating hidden wiring with light indication

A small copper wire of 5–15 cm is used here as a small antenna. When the device finds wires in the walls or ceiling, a characteristic crackling sound is produced. The sound piezoelectric element is connected to the detector using a bridge circuit that controls the volume level.

Diagram of a device with a light and sound annunciator (indication)

This simple circuit will only require one chip.

Diagram of the detector with light and sound indication

The resistor value of R1 must be equal to 50 MOhm or greater than this figure. An LED light bulb for indication is used without any restrictions on the degree of resistance, since this microcircuit can perform the task assigned to it without “outside help”.

Circuit diagram of a field-effect transistor device

Devices of this type are quite responsive to a stable electric field. This device characteristic is used in the circuit shown below.

Assembly diagram of a device using a field-effect resistor

Such a detector can be made independently without the use of special devices. The voltage indicator should be from 3 to 5 V. To operate this device, so little electric current is required that it can function for about six hours without turning off. The antenna coil is attached using a 0.3–0.5 mm wire to a special Ø 3 mm core. The number of revolutions will depend on the thickness of the wire. If its diameter is Ø 0.3 mm, 20 turns will be required, and if its diameter is 0.5 mm - 50 turns. The antenna works well both with and without the frame.

Metal detector

The metal detector circuit looks like this:

Metal detector circuit diagrams

• Frequency generator VT1 (100 kilohertz).
• Detector - VT2.
• Indication - VT3, VT4.

The generator coils are wound on a special ferrite core. Rod – Ø 8 mm. The number of turns on 1 coil is 120 revolutions, on 2 – 45 revolutions. The recommended wire is PEVTL0.35.

The metal detector is set up away from all steel objects. The adjustment is carried out with special resistors R3 and R5 so that the generation process is significantly reduced (flashing glow of the diode light bulb and low brightness). Then R3 is adjusted to make the emitter go out.

The second step is to adjust the degree of sensitivity. This process is carried out using a small metal object and several resistors. Experts recommend adjusting sensitivity with some regularity. To optimize the process and convenience, regulators are built into the detector body.

The configured metal detector starts working when the antenna is close to metal elements - the light lights up or blinks.

Wiring detector without batteries

This device operates from the electrical network. This circuit operates through the use of a high-capacity capacitor (indicated C1 in the diagram). The capacitor is charged from the mains and in this state can transmit voltage from 6 to 10 V. Here, the brightness of the LED light bulb will depend on the degree of voltage, but this indicator does not affect the operation of the device.

When assembling, you can use an LED or a piezo emitter. When a magnetic field is detected, the indicator begins to work (the light comes on or the emitter begins to crackle).

Such a device can only respond to a certain frequency of 50 Hz. Therefore, errors during operation are excluded here, since it will not respond to other types of frequencies.

Two-element device for finding hidden wiring

It uses a microcircuit and a diode light bulb. You can take a DD1 type microcircuit and an HL1 light bulb. It is necessary to connect the leads so that 3 inverters are created in the electrical circuit. Due to this, the device will amplify the currents supplied to the finder from the magnetic field of the wires. When they are close, the light begins to blink. At a distance it goes out.

Assembly diagram of a two-element detector for finding hidden wiring

Attention! The KP103 transistor can be used of any type, as well as the AL307 light bulb. The whole point is that biopolar poles with such a degree of conductivity have low power, but the transmission coefficient is high. Therefore, instead of the KT203 device, it is necessary to use KT361.

The device is small in size, so it can be assembled even in an empty case from a regular stationery marker. A thin antenna is pulled through a small hole in the felt-tip pen. Its length can vary from 5 to 10 cm. But if the wires are not too deep in the wall (no more than 10 cm), then you can simply use the leg of the selected transistor. It will be easier and more convenient this way.

The transistor itself is mounted in a horizontal position, and the gate must be bent so that it is directly above its body.

Video: how to assemble a hidden wiring detector according to the circuit diagram

As many years of experience and practice show, it is not necessary to buy a detector for finding hidden wiring and breaks in a specialized store, since if necessary, you can easily make it yourself, having at least a little experience working with electrical appliances. Such home devices also cope well with their “responsibilities” and find hidden wires.

How to make a hidden wiring detector with your own hands. How to make a cable reel with your own hands. DIY cable reel. If you are the happy owner of a large yard and often use power tools for household purposes, then you know how difficult it is sometimes to cope with an electric carry that is a couple of tens of meters long. The wire gets tangled, intertwined and can take hours to untangle. DIY hidden wiring detector diagram. Surely many people had to hammer a nail into the wall to hang a picture, but what if there was wiring there? So I was faced with the task of finding the wiring in the wall so as not to damage it.

Materials and tools
To assemble the detector we will need: three diodes marked 2N3904, a resistor with a resistance of 1 MOhm, a resistor with a resistance of 100 kiloohms, a resistor with a resistance of 220 Ohms, any plastic card, an LED, a switch and 10-15 cm of copper wire.

Well, I’ll also attach a circuit diagram of the detector.

Now we bend the base leg back, the emitter leg forward, and the collector leg to the left and do this on all three transistors, these will be our blanks.

Then it is necessary to solder these three transistors together and at the same time the emitter leg must be soldered to the base leg of the next transistor, or, more simply, each right leg is soldered to the middle leg of the other transistor. Then we solder a resistor to the collector leg of each transistor.

After this, we add an LED to our design, as shown in the picture.

Then we need to solder a copper wire to the base leg of our first transistor, it will serve as an antenna, it should turn out something like this.

Then we take a plastic card and use hot glue to glue our design to the card, also solder the switch, glue the box for the batteries and that’s it, our design is ready.

Well, now the test. I will show an example on the wall where hidden wiring goes up from the switch.

As long as I move the device along the wire placement line, the LED lights up, but as soon as I move it to the side, it goes out. A very useful thing for those who do not know how the cable is laid in the wall.

Electromagnetic radiation is constantly around us, but it is inaccessible to human hearing. If you want to hear electromagnetic radiation, you can use a special device that we will make with our own hands.

To make an electromagnetic radiation detector we will need:
- old cassette player;
- glue;

The cassette player needs to be disassembled and the board removed from the case itself. It is recommended to familiarize yourself with the board not only for self-development, but also to ensure that no parts are broken when assembling and disassembling this device. This part is very sensitive to electromagnetic waves.

The most important part on the board is the read head, which will be useful to us later.

There are two wires near the read head, which are secured with bolts. These bolts will need to be unscrewed. After unscrewing the bolts, the reading head should remain, which will hang on the cable. You need to be extremely careful with it so as not to tear it off.

If the player does not have an external speaker, then we connect ordinary headphones to a special connector, which will help us hear electromagnetic waves.

Now we lean the read head against the TV. We can hear electromagnetic radiation. The radiation can be heard at a distance of up to 40 cm, the further we move away, the worse the sound will be heard. It is important to note that the old TV (cube) gives us a lot of radiation.

If we connect our device to a new generation of TVs (liquid crystal), we will also hear interference, but not so strong.
A big surprise was the fact that even the TV remote control emits electromagnetic radiation.

It's no secret that radiation also comes from the phone. When tested, the sound was similar to when you make a call and have your speakers turned on. The radiation comes from absolutely any phone, even the coolest and most sophisticated one, and you don’t have to dial the number, you can go online.

Even ordinary phone chargers and door handles emit electromagnetic radiation.

Using a regular player, you can hear radiation that is not heard by the ears and not seen by the eyes.

Do you want to know if your loved one is cheating on you? Or maybe you're working on a science project?

This simple lie detector can be done at home using fairly simple electronic devices. If you are a child, please ask an adult to help you.

Read also:

1. Find something suitable that you will use as an electrode (conductor). You can use metal alligator clips, but this may cause harm to the person you are testing.

Can be used to make a home lie detector electrode pads for hospital equipment, but requires the use of wire and electrical tape.

2. Assemble the circuit according to the diagram.

Do not attempt to test the device on a person until you have fully assembled it.

3. Attach the electrode to the back of the subject's hand.

Place the electrodes at a distance of approximately 2.5 cm. Place the measuring device where the current strength is zero. If the instrument readings begin to fluctuate, it means the subject is lying.

4. Resistance measurement:

This DIY lie detector is based on measuring skin resistance. When you tell a lie human skin loses part of its ability to resist pressure. Such a system will measure the subject's resistance and alert you when a lie is told. Keep in mind that this system is very simplified compared to professional detectors.