5 diagrams for manual assembly of a wiring finder. Top 8 most popular devices with prices, advantages and disadvantages. Top 4 detectors on AliExpress.
TEST:
- Is it necessary to ground the soldering iron when assembling a finder with a field-effect transistor:
- When assembling a break finder, in what position should KP 103 be installed:
A. in horizontal;
b. in vertical.
- What resistance is needed for the wire when assembling a finder using a radio:
- What resistance is needed for the speaker when assembling a device based on a field-effect transistor:
A. 3000-5000 Ohm;
b. 1600-2200 Ohm.
- What resistor will be needed when assembling a finder using Arduino?
Answers:
There are situations when you need to find wires, running deep into the wall. A special device that you can make yourself will help you find them. Using a simple circuit, anyone can build this device.
4 steps to build a highly sensitive device yourself
To assemble a simple wire finder device you need:
- Prepare materials: a metal rod, a wire for winding around a transformer (with a resistance of 500 ohms), a cable from a microphone with a connector, a radio into which you can insert a microphone.
- Wind the wire around a metal rod.
- Solder the ends of the wires to the cable and make insulation.
- Insert the cable connector into the radio.
After detector ready, you will need to turn on the radio at the highest volume and move the coil along the wall. A changing sound will indicate the presence of wires.
1st diagram for assembling the detector
Look at the picture, which shows the assembly of a wiring finder using a field-effect transistor.
Rice. 1 Assembly based on a field-effect transistor The device works on the principle of finding electric field. To assemble a simple wiring finder using a field-effect transistor, you need:
- Soldering iron, rosin, solder.
- Knife, wire cutters, tweezers.
- Field effect transistor (KP 303, KP 103, Kt 315).
- A speaker with an impedance of 1600 to 2200 ohms.
- Battery (15-9 V).
- Switch.
- Wires.
- Plastic container for mounting parts.
The speaker will emit noise, which will increase when brought to electrical wires.
2nd scheme: with adjustable sensitivity
Look at the picture showing an assembly option for a wiring detector whose sensitivity can be adjusted.
Explanation of circuit symbols:
- T-KP 103;
- HL – AL107BL;
- R1 – 2.0 kOhm;
- R2 – 2.0 kOhm;
- R3 – 1.0 Mohm;
- C1 – 5.0 µF;
- C2 – 20.0 µF;
- SP – speaker whose resistance is from 30 to 60 Ohms;
- L – 20-50 turns of wire with a diameter of 0.3 – 0.5 mm.
3rd circuit break finder
Look at the picture to help you assemble the cliff finder. wiring.
This device will allow you to detect not only the wire, but also record its break. Pay attention to some of its characteristics:
- The device is compact;
- antenna size – 5-10 cm;
- The VT1 sensor is very sensitive. When its shutter is close to the wiring, the LED will light up.
Important! When assembling, KP 103 is installed in a horizontal position. The gate is bent to place it above the transistor.
4th circuit: using Arduino
Look at the picture showing the build of the finder using two transistors.
Arduino– trade name of hardware and software for assembling light automation systems. Software component: software shell for creating programs, hardware – assembled printed circuit boards. It is intended for non-professional users.
To assemble the device you need: controller (board) Arduino, resistor 3.3 MΩ, LED, wire.
- Connect the LED between ground and 11 PWM pin of the controller.
- Place a resistor between ground and the fifth analog input.
- Connect the wire to the same contact.
- Connect Arduino to PC.
- Upload the sketch:
int inPin = 5;
int val = 0;
int pin11 = 11;void setup()
{
Serial.begin(9600);
}void loop()
{
val = analogRead(inPin);
if(val >= 1)
{
val = constrain(val, 1, 100);
val = map(val, 1, 100, 1, 255);
analogWrite(pin11, val);
}
else
{
analogWrite(pin11, 0);
}
Serial.println(val);
}Sketch- This special program, created for Arduino. To fill the sketch you need:
- Open the program.
- Copy and paste the sketch.
- Click the fill button.
Then it will happen compilation(converting program code into binary code that the controller will execute). Then, if there are no errors, sketch will be flooded. When you bring the device to the outlet, the LED will light up.
Below is a visual example of filling:
Rice. 5 Example of sketch filling.
Important! It is necessary to power the controller from the battery, since the computer is a source of electromagnetic field. This picture will allow you to assemble a finder using a microcircuit K561La7. For assembly you will need: microcircuit, LED (AL 307, AL 336), battery 3-15 V.
The main point: at the input, the antenna supplies signal. The presence of voltage will be indicated by a lit LED. Logic elements (AND-NOT) are entered in sequential mode, since the outputs of the K561La7 inverse(if there is a signal at the input, then it is absent at the output).
Top 8 devices. Review rating. Which to choose. The best searcher according to the editors
The market offers a wide range of different detectors wire detection. Based on consumer reviews, you can make a rating of devices offered on the market and choose the best one.
ADA Wall Scanner 50
Identifies ferrous and non-ferrous metals, wiring and communication lines.
Search depth: wires (mm) - 50, metal - 50. Weight: 12 Dimensions: 225x130x30(mm).
Reviews: good, unprofessional, identifies wires, but there are mistakes, low price.
Dyi Duwi
The device calculates metal and wiring.
Detection depth: metal – 24 mm, wires – 30 mm. Nutrition: Krona batteries.
Reviews: good equipment, low price, but there are errors in the search.
Rst tc 15
The device detects metal and cable with electric shock Search depth: metal – 38 mm, copper – 19 mm, cable – 50 mm. Runs on Krona batteries. There is an auto shutdown mode and a discharge indicator. Dimensions: 115x70x50 (mm).
Reviews: good device, reasonable price, precise definition wiring.
Bosch GMS 120
Device detects metal: ferrous and non-ferrous, electrical wiring. Calculation depth (mm): wood – 38, metals – 120, wiring – 50. Powered by Krona batteries. Dimensions (mm): 120x80x50. Reviews: good device, high price.
DSL 8220
Detects closed wiring, communication lines, antenna wires. Has light and sound warning. Weight 200 g. Dimensions: 195x50x20 (mm). Depth search up to 20 mm. Runs on Krona batteries.
But it was LED (the LED lit up in response to the wiring). But this time it’s a sound wiring detector. When a wire is detected, a crackling sound is emitted; the closer the wire, the more intense the crackling sound.
Based on the Soviet microcircuit K561LA7. Operating on field-effect transistors. This warning is due to the fact that the soldering iron must be grounded before soldering and the power must not exceed 60 watts.
The supply voltage of the microcircuit is from 3 to 18 V. So it’s not difficult to select the power supply. Batteries from phones, crowns, etc. are suitable. which significantly reduces the size of the device.
In my case it is a phone battery.
We need a microcircuit, a resistance of 1 MOhm, a piece of single-core copper wire (8 to 15 cm long - this will be the antenna), a tweeter (you can use an old working earphone) and a power source.
Empty box - I used an outdated USB adapter. And he took out all the insides. The size was just right for the battery.
It’s not worth paying for such a small thing.
So I took a small piece of cardboard. I marked where the holes needed to be made and pierced them with a regular pin.
We bend the ends to the sides so that they do not interfere with soldering.
And here is the most simple circuit for soldering.
We solder everything carefully.
We check the device for functionality, if everything works fine, we make a screen (isolate the microcircuit from interference).
Fill everything well with hot glue.
Then, when the glue dries, wrap the entire circuit in food foil.
We pack everything into a case.
Let's check.
Drilling a hole for a dowel screw or nail in the wall is not difficult. The main thing is that when perforating, do not stumble upon hidden wiring and damage it. A detector helps to detect a break or a live electrical cable in the wall. hidden wiring. In order not to spend extra money, we will construct a simple detector based on the K561LA7 microcircuit, and talk about the selection criteria and advantages of factory-made devices.
Homemade detector with a piezoelectric element - simple words about the complex
Hidden wiring detectors are divided into low and high class devices. A low-class device is designed to search for electrical appliances and live wiring. A high-class detector has greater sensitivity and advanced functionality. Such a device is used to determine the breakage of hidden wiring and detects the location of wires without voltage.
You can make a hidden wiring detector with your own hands from available materials by purchasing several small parts. When designing this device, keep in mind that it is suitable for detecting live wiring in a wall. And if you need high-frequency equipment to detect a break and the exact location of a cable down to the millimeter, purchase a high-quality detector in the store.
To assemble the device you will need the following set of elements:
- microcircuit K561LA7;
- 9 V Krona battery;
- connector, battery connector;
- current limiter (resistor) with a nominal resistance of 1 MΩ;
- sound piezoelectric element;
- single-core copper wire or wire L= 5–15 cm;
- wiring for soldering contacts;
- wooden ruler, power supply box, another homemade design for laying the chain.
Additionally, for work you will need a low-power soldering iron up to 25 W, so as not to overheat the microcircuit; rosin; solder; wire cutters Before we begin assembly, let's take a closer look at the main elements. The main part on which the assembly takes place is a Soviet-type K561LA7 microcircuit. It can be found on the radio market or in old stock. The K561LA7 microcircuit is sensitive to static and electromagnetic fields, which create electrical devices and conductors. The current level in the system is controlled by a resistor, which is located between the integrated circuit and the antenna. We use single-core copper wire as an antenna. The length of this element affects the sensitivity of the device and is selected experimentally.
When selecting the length of the copper wire, ensure that it only responds to the electrical cable. This will allow you to determine the exact location of the wiring in the wall.
Another important assembly detail is the piezoelectric element. Catching an electromagnetic signal, it creates a characteristic crackling sound, which signals the presence of wiring in a given location. It is not necessary to specifically purchase the part; take out the speaker from an old player or toy (Tetris, Tamagotchi, watch, sound machine). Instead of a speaker, you can solder headphones. The sound will be cleaner and you won't have to listen to the crackling noise. As an indicator of hidden wiring, you can additionally install an LED element into the device. The circuit is powered by a 9-volt Krona battery.
To make it more convenient for you to work with the microcircuit, take cardboard or foam plastic and mark with a needle the places for attaching the 14 legs (legs) of the part. Then insert the legs of the integrated circuit into them and number them from 1 to 14, starting from left to right with the legs facing up.
We make connections in the following sequence:
- 1. Prepare a box where we will place the parts after assembly. For a cheap alternative, use a plastic bottle cap. Make a hole in the end with a knife with a diameter of about 5 mm.
- 2. Insert a hollow rod into the resulting hole, for example, a base from ballpoint pen, suitable for the diameter, which will be the handle (holder).
- 3. Take a soldering iron and solder a 1 MΩ resistor to pin 1–2 of the microcircuit, covering both contacts.
- 4. Solder the first wire of the speaker to the 4th leg, after which we close the 5th and 6th legs together, solder them and connect the second end of the piezoelectric element wire.
- 5. We close legs 3 and 5–6 with a short wire, forming a jumper.
- 6. Solder the copper wire to the end of the resistor.
- 7. We pull the wires of the connector (battery connector) through the handle. We solder the red wire (with a positive charge) to leg 14, and the black wire (with a negative charge) to leg 7.
- 8. From the other end of the plastic cap (box) we make a hole for the copper wire to exit. We place a microcircuit with wiring inside the lid.
- 9. Close the lid on top with the speaker, fixing it on the sides with hot glue.
- 10. Straighten the copper wire vertically and connect the battery to the connector.
The wiring detector is ready. If you have connected all the elements correctly, the device will work. If possible, we recommend equipping the system with a switch or removing the battery from the connector after finishing work in order to save power and not overload the system.
A device with an LED is the second option for assembling the system
The simplest device for finding hidden wiring with LED indicator assembled according to a similar scheme. To assemble the system you will need: an LED, a 9 V Krona battery, thin wires, a copper wire (5–15 cm), a connector for the battery (connector), a connector for the microcircuit and the K561LA7 microcircuit itself. The set of tools is unchanged - low power soldering iron, rosin, soldering, wire cutters.
We solder the antenna (copper wire) so that it closes pins 1 and 2 of the microcircuit. We close legs 3, 5, 12 and 13 together, first soldering the horseshoe loop. After this, we make a jumper from the wires for legs 4, 8 and 9. Next, we connect the LED, an indicator of hidden wiring, with a positive charge to the 14th leg, and a negative charge to the 7th leg. We solder the battery connector (connector) (–) to the 7th leg, and (+) to the 14th leg. We close the assembled K561LA7 microcircuit with the connector, first bending the legs inward. We insert the battery into the connector and check the device. When the detector antenna is brought close to hidden wiring, the LED lights up. To make the device more neat and convenient, place assembled circuit into a box, for example, from an old power supply, if necessary, making the necessary holes for the outlet.
Groups of detectors - types and purpose
All detectors for detecting wiring are divided into 4 types: electrostatic, electromagnetic, metal detectors, combined (universal) types. Let's look at each group.
Electrostatic devices belong to the budget class. They are easy to use, but have a small range of capabilities and are only suitable for detecting live wiring. Also, the device often malfunctions, reacts sensitively to the presence of foreign metal objects in the wall, and operates in a humid environment. This device is optimal for searching for wiring in an apartment. In damp rooms (bathrooms, basements, balconies, bathhouses), the quality of the electrostatic detector will be extremely low.
Electromagnetic detectors are of higher quality and more reliable in operation. Such devices are used to search for de-energized wiring and at low voltage, although errors cannot be excluded. To obtain accurate readings, the load in the circuit when operating electromagnetic detectors should be about 1 kW.
Metal detectors are also used to detect wiring inside walls. However, their main problem is that the wiring finder reacts to the presence of all metal objects, be it a nail or a screw, which is why the accuracy of the device in detecting the exact location of the wiring is reduced. Detection of hidden wiring without voltage using a metal detector gives good results. The signal is given by sound or a flashing LED.
The most accurate results are obtained with combined (universal) models that combine the functions of all previous devices. Universal detectors allow you to find out not only about the location of the wiring, but also its depth, the type of metal in the wire strands, and the presence or absence of voltage. Multidetectors belong to a series of combined options. In addition to wires, they find plastic pipes, wooden elements and non-ferrous metal structures in the wall.
Choosing a device in a store – what to look for?
To decide which detector is better, we present the main characteristics by which the device is divided into quality and functionality. When choosing a device for detecting hidden wiring, pay attention to:
- scanning depth;
- type of signal (sound or color);
- the ability to detect a break;
- difference in types of structures and wiring in the wall.
Scanning depth is one of the main indicators of a quality device. The budget determinant reacts to the location of hidden wiring at a depth of 1–2 cm or, in other words, the occurrence of wiring under a layer of plaster. This indicator is not enough for working at home, so for correct operation we recommend purchasing a detector that scans wiring in the wall to a depth of 5–6 cm. Wires in apartments and private houses are rarely laid deeper, so you should not overpay for this parameter.
When choosing the type of signal, give preference to combined options with a sound and color signal. This choice allows you to reduce errors to a minimum. Special attention Pay attention to the transmission of the sound signal, choosing devices with a change in tone. As the detector approaches or moves away from the wiring, the sound melody changes from low to high and vice versa. If you need accuracy, choose a detector with an LCD display, it allows you to locate hidden wiring with details. Information is displayed on the screen in the form of icons and bars. Regardless of the type of device, it must be tested before purchasing.
When choosing a simple design for one-time work, focus on purchasing an electromagnetic detector. The indicator screwdriver is a classic example of such a device. For correct operation, use contactless battery-powered devices that can pick up weak signals. Appearance indicator screwdriver does not affect its quality, but only its convenience. This device is suitable for detecting hidden wiring under a thin layer of plaster. For searching in concrete and brickwork, look for other options.
In addition, the electromagnetic device is not suitable for use in damp rooms and conditions. If this parameter is important to you, consider purchasing a universal device. Such detectors have advanced functions, we recommend that you familiarize yourself with them. You may not need full functionality, so before buying expensive devices, consider the purpose of use. For one-time work, an indicator screwdriver or a simple electrostatic device is sufficient. In professional daily activities, you cannot do without a universal device.
Bosch, Black&Decker detector - a brief overview of popular series
If you are looking for a high-quality, middle-class device for hidden wiring, experts recommend Bosch detectors. Among the series of this manufacturer, the Bosch GMS 120 Prof model is distinguished. What makes it special? It has a deep scanning, about 12 cm, detects metal objects (copper, steel, ferrous metal), live wiring, wood, plastic pipes. Wide functionality allows you to select scanning material. A signal about the location of the desired item is given by sound and color. Among additional functions– the ability to mark points for perforation in the wall. Bosch GMS 120 Prof runs on regular batteries. The main advantages of the device: simple interface, convenient adjustment of control modes, point measurement, complete display of information about the object and deep scanning.
Black&Decker devices are also widely used among craftsmen for detecting hidden wiring and searching for dissimilar materials, with the exception of wood. Consider the BDS200 model. It has mode adjustment, which allows you to control the sensitivity of the device, and a shockproof housing. Black&Decker BDS200 is equipped with a sound and color signal, which is displayed on the device display.
Woodpecker device – what does the Russian manufacturer offer?
To determine hidden wiring, technicians use a device from the domestic manufacturer Dyatel. Three main advantages of the detector: quality, affordable price, availability of basic functions for operation. How does the device work? The device reacts to the predominance of the electrostatic field; when it hits resonance, the device emits a sound signal, which intensifies as it approaches the hidden wiring. However, the device only detects vibrations coming from the live wire. The Woodpecker detector does not detect a de-energized cable. The device has a built-in regulator and a self-monitoring mode that controls the sensitivity of the detector. The device is lightweight, weighing no more than 250 g. The detector is suitable for determining:
- hidden wiring in all ceilings (walls, ceiling, floor);
- broken wiring;
- correct connection of the electric meter circuit, without removing seals and terminal blocks;
- phase wire;
- voltage in the contact network;
- ungrounded installation;
- electromagnetic fields created by household appliances;
- correct operation of fusible parts and fuses.
In order for the purchased detector to please you with stable operation, we take into account the following features. The wiring is laid in a vertical and horizontal position. To make the search for hidden wiring faster, we move in these directions. At the point with the highest signal level we put a mark and move the antenna a little further from it. The electrical cable is located between the two points. If the signal has the same intensity throughout the entire area, it is possible that, in addition to the electrical cable, there is a metal structure in the ceiling, for example, a sheathing. To reduce sensitivity, place your hand against the wall.
Quite often, residents of apartment buildings need to attach a picture, hanger, shelf or some other piece of furniture to the wall of their apartment. To do this, you need to mark a point on the wall and drill a small hole with a hammer drill. However, there is always the possibility of getting caught in the wiring hidden in the wall under the wallpaper - in this case, a small renovation of the interior may result in the inevitable call to the electricians. To prevent this from happening, you can assemble a simple hidden wiring detector that will show exactly where the wires are and where they are not.
Scheme
The sensitive element of the circuit is a field-effect transistor KP103, to the gate of which an antenna is connected. You can use a transistor in any package and with any letter index. The device reacts to wires under voltage of 220 V 50 Hz, regardless of whether current flows through them or not. The circuit also uses the K561LA7 microcircuit, which represents 4 logic gate 2I-NOT. It can be replaced with an imported analogue, the CD4011 microcircuit. The LED on the circuit lights up when the antenna is in close proximity to a live wire. As an antenna, you can use a piece of ordinary thin wire, 5-10 cm long. The longer its length, the greater the sensitivity of the device. The circuit consumes approximately 10-15 mA and is powered by a voltage of 9 volts. A regular Krona battery is suitable for power supply. If necessary, any piezoceramic emitter, for example, ZP-3, can be connected to pin 10 of the microcircuit, then a sound will be heard when a wire is detected.
Detector assembly
The circuit is assembled on a miniature printed circuit board measuring 40 x 30 mm, which can be made using the LUT method. The printed circuit board is completely ready for printing; there is no need to mirror it. After etching, it is advisable to tin the tracks; this will simplify the soldering of parts, and the copper will not oxidize.
After manufacturing the printed circuit board, you can solder the parts. You should be careful when handling the microcircuit - it is sensitive to static and can be easily damaged. Therefore, we solder the socket for the microcircuit onto the board and place the microcircuit in it only after the assembly is completed. You also need to be careful when soldering the transistor - if it is in a plastic case, then only two legs are soldered onto the board - drain and source, and the antenna is soldered directly to the gate. If the case is metal, all three legs are soldered onto the board along with the antenna. It is important not to mix up the pinout, otherwise the device will not work. For convenience, the power wires can be immediately soldered to the connector for Krona, as I did. After completing soldering, be sure to wash off any remaining flux from the board, otherwise sensitivity may be affected. It is also advisable to check the correct installation and adjacent tracks for short circuits.
Detector tests
After assembly is completed, testing can begin. We take the crown and connect it to the board, placing an ammeter in the gap of one of the wires. The circuit consumption should be 10-15 mA. If the current is normal, you can bring the detector antenna to any network wire and watch how the LED lights up and the piezo emitter beeps, if installed. The wire detection range is approximately 3-5 cm, depending on the length of the antenna. In this case, you should not touch the antenna, as this will significantly reduce the sensitivity. The device does not require any setup and starts working immediately after power is applied. In addition to network wires, it also responds to twisted pair cable. Happy assembly.
The video clearly shows how such a detector works. With its help, you can accurately determine where the wires from the switch run.