Home Steering Smooth fading of LEDs in cars. Manufacturing of boards and assembly of devices for smooth ignition of LEDs. For work we need

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Smooth fading of LEDs in cars. Manufacturing of boards and assembly of devices for smooth ignition of LEDs. For work we need

In addition to a purely decorative function, for example, illumination of a car showroom, the use of soft switching, or ignition, has a fundamental practical significance for LEDs - a significant extension of service life. Therefore, we will consider how to make a device with your own hands to solve such a problem, whether it is worth making it yourself or is it better to buy a ready-made one, what is required for this, as well as what circuit options are available for amateur production.

The first question that arises when it is necessary to include a soft ignition module for LEDs in the circuit is whether to make it yourself or buy it. Naturally, it is easier to purchase a ready-made block with specified parameters. However, this method of solving the problem has one serious disadvantage - the price. When making it yourself, the cost of such a device will decrease several times. In addition, the assembly process does not take much time. In addition, there are proven options for the device - all that remains is to acquire the necessary components and equipment and connect them correctly, in accordance with the instructions.

Note! LED lighting is widely used in cars. For example, these could be daytime running lights and interior lighting. The inclusion of a smooth ignition block for LED lamps allows, in the first case, to significantly extend the life of the optics, and in the second, to prevent the driver and passengers from being blinded by the sudden switching on of a light bulb in the cabin, which makes the lighting system more visually comfortable.

What do you need

To properly assemble a soft ignition module for LEDs, you will need a set of the following tools and materials:

Soldering station and set of consumables (solder, flux, etc.).
A fragment of a textolite sheet for creating a board.
Housing for placing components.
The necessary semiconductor elements are transistors, resistors, capacitors, diodes, ice crystals.

However, before you start making your own soft start/damping unit for LEDs, you need to familiarize yourself with the principle of its operation.

The image shows a diagram of the simplest model of the device:

It has three working elements:

Resistor (R).
Capacitor module (C).
LED (HL).

A resistor-capacitor circuit based on the RC delay principle essentially controls the ignition parameters. So, the greater the value of resistance and capacitance, the longer the period or the smoother the switching on of the ice element occurs, and vice versa.

Recommendation! At the moment, a huge number of soft ignition block circuits for 12V LEDs have been developed. They all differ in their characteristic set of pros, cons, level of complexity and quality. There is no reason to independently manufacture devices with extensive circuit boards using expensive components. The easiest way is to make a module on one transistor with a small connection, sufficient for slow turning on and off of an ice light bulb.

Schemes for smooth switching on and off of LEDs

There are two popular and self-manufacturing options for soft ignition circuits for LEDs:

The simplest.
With function for setting the start period.

Read also Dynamic monitor backlight: characteristics, diagram, settings

Let's consider what elements they consist of, what is the algorithm of their operation and the main features.

A simple scheme for smoothly turning on and off LEDs

Only at first glance, the smooth ignition diagram presented below may seem simplified. In fact, it is very reliable, inexpensive and has many advantages.

It is based on the following components:

IRF540 is a field-effect transistor (VT1).
Capacitive capacitor 220 mF, rated at 16 volts (C1).
A chain of resistors of 12, 22 and 40 kiloOhms (R1, R2, R3).
Led crystal.

The device operates from a 12 V DC power supply according to the following principle:

When the circuit is energized, current begins to flow through block R2.
Thanks to this, element C1 is gradually charged (the capacity rating increases), which in turn contributes to the slow opening of the VT module.
The increasing potential at pin 1 (field gate) provokes the flow of current through R1, which contributes to the gradual opening of pin 2 (VT drain).
As a result, the current passes to the source of the field unit and to the load and ensures smooth ignition of the LED.

The process of extinction of the ice element follows the reverse principle - after removing the power (opening the “control plus”). In this case, the capacitor module, gradually discharging, transfers the capacitance potential to blocks R1 and R2. The speed of the process is regulated by the rating of the element R3.

The main element in the smooth ignition system for LEDs is the MOSFET IRF540 n-channel field-effect transistor (as an option, you can use the Russian model KP540).

The remaining components relate to the harness and are of secondary importance. Therefore, it would be useful to present its main parameters here:

Drain current is within 23A.
The polarity value is n.
Drain-source voltage rating is 100V.

Important! Due to the fact that the speed of ignition and attenuation of the LED depends entirely on the value of resistance R3, you can select the required value to set a certain time for the soft start and shutdown of the ice lamp. In this case, the selection rule is simple - the higher the resistance, the longer the ignition, and vice versa.

Improved version with the ability to customize the time

Often there is a need to change the period of smooth ignition of LEDs. The scheme discussed above does not provide such an opportunity. Therefore, it is necessary to introduce two more semiconductor components into it - R4 and R5. With their help, you can set resistance parameters and thereby control the ignition speed of the diodes.

Do-it-yourself smooth switching on and dimming of LEDs

What's happened smooth start, or otherwise ignition LEDs I think they all represent.

Let's look at it in detail do-it-yourself smooth switching on of LEDs.

The LEDs should not light up immediately, but after 3-4 seconds, but initially not blink or light up at all.

Device diagram:

Components:

■ Transistor IRF9540N
■ Transistor KT503
■ Rectifier diode 1N4148
■ Capacitor 25V100µF
■ Resistors:
- R1: 4.7 kOhm 0.25 W
- R2: 68 kOhm 0.25 W
- R3: 51 kOhm 0.25 W
- R4: 10 kOhm 0.25 W
■ One-sided fiberglass and ferric chloride
■ Screw terminal blocks, 2 and 3 pins, 5 mm

You can change the ignition and decay time of the LEDs by selecting the value of resistance R2, as well as selecting the capacitance of the capacitor.

There are many ways to cut PCB: with a hacksaw, metal scissors, using an engraver, and so on.

Using a utility knife, I made grooves along the marked lines, then sawed them out with a hacksaw and sharpened the edges with a file. I also tried using metal scissors - it turned out to be much easier, more convenient and dust-free.

Next, sand the workpiece under water with P800-1000 grit sandpaper. Then we dry and degrease the surface of the board with 646 solvent using a lint-free cloth. After this, it is not advisable to touch the surface of the board with your hands.

To do this, when printing in the program, at the top left in the “layers” section, uncheck unnecessary boxes. Also, when printing, in the printer settings we set high definition and maximum image quality. Using masking tape, glue a glossy magazine page/glossy photo paper (if their size is smaller than A4) onto a regular A4 sheet and print our diagram on it. I tried using tracing paper, glossy magazine pages and photo paper. It is most convenient, of course, to work with photographic paper, but in the absence of the latter, even magazine pages will do just fine. I don’t recommend using tracing paper - the design on the board is printed very poorly and will turn out unclear.

Now we warm up the textolite and attach our printout. Then use an iron with good pressure to iron the board for several minutes.

Now let the board cool completely, then put it in a container of cold water for a few minutes and carefully remove the paper from the board. If it doesn’t come off completely, then roll it up slowly with your fingers.

Then we check the quality of the printed tracks, and touch up the bad places with a thin permanent marker.

Using double-sided tape, glue the board onto a piece of foam plastic and place it in a ferric chloride solution for several minutes. The etching time depends on many parameters, so we periodically remove and check our board. We use anhydrous ferric chloride, dilute it in warm water according to the proportions indicated on the package. To speed up the etching process, you can periodically shake the container with the solution.

After the unnecessary copper has been removed, we wash the board in water. Then, using a solvent or sandpaper, remove the toner from the tracks.

Then you need to drill holes for mounting the board elements. To do this, I used a drill (engraver) and drills with a diameter of 0.6 mm and 0.8 mm (due to the different thickness of the legs of the elements).

Next you need to tin the board. There are many different ways, I decided to use one of the simplest and most accessible. Using a brush, we lubricate the board with flux (for example LTI-120) and tin the tracks with a soldering iron. The main thing is not to keep the soldering iron tip in one place, otherwise the tracks may come off due to overheating. We take more solder onto the tip and move it along the path.

Now we solder the necessary elements according to the diagram. For convenience inSprintLayotI printed out a diagram with symbols on plain paper and, when soldering, checked the correct arrangement of the elements.

After soldering, it is very important to completely wash off the flux, otherwise there may be shorts between the conductors (depending on the flux used). First, I recommend thoroughly wiping the board with 646 solvent, and then rinsing it well with a brush and soap and drying it.

After drying, we connect the “constant plus” and “minus” of the board to the power supply (“control plus” is not touched), then instead of the LED strip we connect a multimeter and check if there is voltage. If at least some voltage is still present, it means there is a short somewhere, perhaps the flux was not washed off well.

Result:

I am satisfied with the work done, although I spent quite a lot of time. The process of making boards using the LUT method seemed interesting and uncomplicated to me. But, despite this, in the process of work I probably made all the mistakes that were possible. But, as they say, you learn from mistakes.

Such a board for smooth ignition of LEDs has a fairly wide range of applications and can be used both in a car (smooth ignition of angel eyes, instrument panels, interior lighting, etc.), and in any other place where there are LEDs and a 12V power supply. For example, in illuminating a computer system unit or decorating suspended ceilings.

On the Internet there are many schemes for smooth ignition and damping of LEDs powered by 12V, which you can do yourself. They all have their advantages and disadvantages and differ in the level of complexity and quality of the electronic circuit. As a rule, in most cases there is no point in building bulky boards with expensive parts. In order for the LED crystal to smoothly gain brightness at the moment of switching on and also smoothly go out at the moment of switching off, one MOS transistor with a small wiring is enough.

Scheme and principle of its operation

Let's consider one of the simplest options for a scheme for smoothly turning on and off LEDs controlled via the positive wire. In addition to ease of execution, this simplest scheme has high reliability and low cost. At the initial moment of time, when the supply voltage is applied, current begins to flow through resistor R2, and capacitor C1 is charged. The voltage across the capacitor cannot change instantly, which contributes to the smooth opening of transistor VT1. The rising gate current (pin 1) passes through R1 and leads to an increase in the positive potential at the drain of the field-effect transistor (pin 2). As a result, the LED load is switched on smoothly.

When the power is turned off, the electrical circuit breaks along the “control plus”. The capacitor begins to discharge, giving energy to resistors R3 and R1. The discharge rate is determined by the value of resistor R3. The greater its resistance, the more accumulated energy will go into the transistor, which means the longer the attenuation process will last.

To be able to adjust the time for complete switching on and off of the load, trimming resistors R4 and R5 can be added to the circuit. At the same time, for correct operation, it is recommended to use the circuit with resistors R2 and R3 of small value.
Any of the circuits can be assembled independently on a small board.

Schematic elements

The main control element is a powerful n-channel MOS transistor IRF540, the drain current of which can reach 23 A, and the drain-source voltage can reach 100V. The circuit solution under consideration does not provide for the operation of the transistor in extreme modes. Therefore, it will not need a radiator.

Instead of IRF540, you can use the domestic analogue KP540.

Resistance R2 is responsible for the smooth ignition of the LEDs. Its value should be in the range of 30–68 kOhm and is selected during the setup process based on personal preferences. Instead, you can install a compact 67 kOhm multi-turn trimmer resistor. In this case, you can adjust the ignition time using a screwdriver.

Resistance R3 is responsible for the smooth fading of the LEDs. The optimal range of its values is 20–51 kOhm. Instead, you can also solder a trimmer resistor to adjust the decay time. It is advisable to solder one constant resistance of a small value in series with trimming resistors R2 and R3. They will always limit the current and prevent a short circuit if the trimming resistors are turned to zero.

Resistance R1 is used to set the gate current. For the IRF540 transistor, a nominal value of 10 kOhm is sufficient. The minimum capacitance of capacitor C1 should be 220 µF with a maximum voltage of 16 V. The capacitance can be increased to 470 µF, which will simultaneously increase the time for complete switching on and off. You can also take a capacitor for a higher voltage, but then you will have to increase the size of the printed circuit board.

Minus control

The above translated diagrams are perfect for use in a car. However, the complexity of some electrical circuits lies in the fact that some of the contacts are connected to the positive, and some to the negative (common wire or body). To control the above circuit by minus power, it needs to be slightly modified. The transistor needs to be replaced with a p-channel one, for example IRF9540N. Connect the negative terminal of the capacitor to the common point of three resistors, and connect the positive terminal to the source of VT1. The modified circuit will have power with reverse polarity, and the control positive contact will be replaced by a negative one.

Read also

The principle of operation of the circuit:

The control “plus” is supplied through a 1N4148 diode and a 4.7 kOhm resistor to the base of the KT503 transistor. At the same time, the transistor opens, and through it and the 68 kOhm resistor the capacitor begins to charge. The voltage on the capacitor gradually increases, and then through a 10 kOhm resistor it is supplied to the input of the field-effect transistor IRF9540. The transistor gradually opens, gradually increasing the voltage at the output of the circuit. When the control voltage is removed, the KT503 transistor closes. The capacitor is discharged to the input of the field-effect transistor IRF9540 through a 51 kOhm resistor. After the capacitor discharge process is completed, the circuit stops consuming current and goes into standby mode. The current consumption in this mode is negligible.

Circuit with control minus:

IRF9540N pinout marked

Circuit with control plus:

IRF9540N and KT503 pinout marked

This time I decided to make the circuit using the LUT method (laser ironing technology). I did this for the first time in my life, I’ll say right away that there is nothing difficult. For work we will need: a laser printer, glossy photo paper (or a page from a glossy magazine) and an iron.

COMPONENTS:

Transistor IRF9540N
Transistor KT503
Rectifier diode 1N4148
Capacitor 25V100µF
Resistors:
- R1: 4.7 kOhm 0.25 W
- R2: 68 kOhm 0.25 W
- R3: 51 kOhm 0.25 W
- R4: 10 kOhm 0.25 W
Single-sided fiberglass and ferric chloride
Screw terminal blocks, 2 and 3 pins, 5 mm

If necessary, you can change the ignition and decay time of the LEDs by selecting the value of resistance R2, as well as selecting the capacitance of the capacitor.

JOB:
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?1? In this post I will show in detail how to make a board with a control plus. The board with a control minus is made in a similar way, even a little simpler due to the smaller number of elements. We mark the boundaries of the future board on the PCB. We make the edges a little larger than the pattern of the paths, and then cut them out. There are many ways to cut PCB: with a hacksaw, metal scissors, using an engraver, and so on.

Next, sand the workpiece under water with P800-1000 grit sandpaper. Then we dry and degrease the surface of the board with 646 solvent using a lint-free cloth. After this, you must not touch the surface of the board with your hands.

2? Next, using the SprintLayot program, open and print the diagram on a laser printer. You only need to print the layer with tracks without markings. To do this, when printing in the program, at the top left in the “layers” section, uncheck unnecessary boxes. Also, when printing, in the printer settings we set high definition and maximum image quality. I uploaded the program and slightly modified diagrams for you to Yandex.Disk.

Using masking tape, glue a glossy magazine page/glossy photo paper (if their size is smaller than A4) onto a regular A4 sheet and print our diagram on it.

I tried using tracing paper, glossy magazine pages and photo paper. It is most convenient, of course, to work with photographic paper, but in the absence of the latter, even magazine pages will do just fine. I don’t recommend using tracing paper - the design on the board is printed very poorly and will turn out unclear.

3? Now we warm up the textolite and attach our printout. Then use an iron with good pressure to iron the board for several minutes.

Then we check the quality of the printed tracks, and touch up the bad places with a thin permanent marker.

4? Using double-sided tape, glue the board onto a piece of foam plastic and place it in a ferric chloride solution for several minutes. The etching time depends on many parameters, so we periodically remove and check our board. We use anhydrous ferric chloride, dilute it in warm water according to the proportions indicated on the package. To speed up the etching process, you can periodically shake the container with the solution.

After the unnecessary copper has been removed, we wash the board in water. Then, using a solvent or sandpaper, remove the toner from the tracks.

5? Then you need to drill holes for mounting the board elements. To do this, I used a drill (engraver) and drills with a diameter of 0.6 mm and 0.8 mm (due to the different thickness of the legs of the elements).

6? Next you need to tin the board. There are many different ways, I decided to use one of the simplest and most accessible. Using a brush, we lubricate the board with flux (for example LTI-120) and tin the tracks with a soldering iron. The main thing is not to keep the soldering iron tip in one place, otherwise the tracks may come off due to overheating. We take more solder onto the tip and move it along the path.

7? Now we solder the necessary elements according to the diagram. For convenience, in SprintLayot I printed out a diagram with symbols on plain paper and, when soldering, checked the correct arrangement of the elements.

8? After soldering, it is very important to completely wash off the flux, otherwise there may be shorts between the conductors (depending on the flux used). First, I recommend thoroughly wiping the board with 646 solvent, and then rinsing it well with a brush and soap and drying it.

PHOTOS:

Shrinked the board

VIDEO:

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I T O G:
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I am satisfied with the work done, although I spent quite a lot of time. The process of making boards using the LUT method seemed interesting and uncomplicated to me. But, despite this, in the process of work I probably made all the mistakes that were possible. But, as they say, you learn from mistakes.

Greetings to all novice electronics engineers and radio engineering enthusiasts and those who like to do something with their own hands. In this article, I will try to kill two birds with one stone: I will try to tell you how to make a printed circuit board of excellent quality yourself, which will be no different from the factory analogue, thereby we will do it with you. This device can be used in a car to connect LEDs. For example, as in .

For work we will need:

Transistors – IRF9540N and KT503;
Capacitor 25 V 100 pF;
Rectifier diode 1N4148;
Resistors:
- R1 – 4.7 kOhm 0.25 W;
- R2 – 68 kOhm 0.25 W;
- R3 – 51 kOhm 0.25 W;
- R4 – 10 kOhm 0.25 W.
Screw terminal blocks, 2 and 3 pins, 5 mm
One-sided textolite and FeCl3 – ferric chloride

Progress.

First of all, we need to prepare the board. To do this, mark the conditional boundaries of the board on the PCB. We make the edges of the board a little larger than the trace pattern. Once you have marked the edges of the borders you can start cutting. You can cut with metal scissors, and if you don’t have them on hand, you can try cutting with a stationery knife.

After cutting out the board, it needs to be sanded. To do this, use sandpaper with a grain size of P800-1000 to sand the board under water. Next we dry and degrease the surface with solvent 646. After which it is not recommended to touch the board.

Next, download the program that is at the end of the article, SprintLayout, and using it, open the board diagram and print it on a laser printer on glossy paper. It is important that when printing, the printer settings are set to high definition and high image quality.

Then you will need to heat the prepared board with an iron and attach our printout to it and iron the board thoroughly for several minutes.

Next, let the board cool a little, then lower it into a cup of cold water for a few minutes. Water will make it easy to tear off the glossy paper from the board. If the gloss has not come off completely, then you can simply roll off the remaining paper slowly with your fingers.

Then you will need to check the quality of the paths; if there are minor damages, you can touch up the bad places with a simple marker.

So, the preparatory stage is completed. Left . To do this, we place our board on double-sided tape and glue it to a small piece of foam plastic and lower it into a ferric chloride solution. To speed up the etching process, you can shake the cup with the solution.

After the excess copper is removed, you will need to wash the board in water and use a solvent to clean the toner from the tracks.

All that remains is to drill the holes. For our device, drills with a diameter of 0.6 and 0.8 mm were used.

It is important not to overheat the tracks, otherwise you may damage them.

All that remains is to assemble our device. It is recommended to first print out the diagram with symbols on plain paper and, using it as a guide, arrange all the elements on the board.

After everything is soldered, you need to completely clean the board of flux. To do this, thoroughly wipe the board with that 646 solvent, wash thoroughly with a brush and soap, and dry.

After drying, we connect and check the functionality of the assembly. To do this, we connect the “constant plus” and “minus” to the power supply and instead of the LEDs, connect a multimeter and check if there is voltage. If there is tension, it means that the flux is not completely disturbed.

As you can see, the board manufacturing process is not a very complicated process. This method of making a board is called LUT (laser ironing technology). As mentioned above, this assembly can be used for ( , , , ), or in any other places where LEDs and 12 volt power are used -

Thank you all for your attention! I will be happy to answer all your questions!

Good luck on the roads!!!

NECESSARILY!!!

Connect devices whose actions and properties are little known to you, especially homemade ones, using fuses.