Slow ignition and attenuation of LEDs is the simplest scheme. Dimming control for LED backlighting of car instruments. Scheme for smooth ignition of LEDs

We will look at smooth switching on of an LED using PWM (PWM) on Arduino on this page. Let's look at how to connect an LED, let's look at what PWM (Pulse Width Modulation) is. We will also take a closer look at the cycle for in the C++ programming language, which is used to repeat statements enclosed in a construct (statements found inside curly braces in a sketch).

Smooth turning on of an LED on Arduino

To remember what Arduino is, we use a simple sketch of a smooth LED switching on. You can use a for loop for this. The header of this construction consists of three parts: for (initialization; condition; increment) - initialization executed once, then the condition is checked condition, if the condition is true, then the increment is performed increment and the cycle repeats as long as the condition is true.

In the example above, we will smoothly change the brightness of the LED using PWM, the LED will smoothly light up and then turn off smoothly. This example can be used for decorative lighting in a room using LEDs or a night lamp controlled by a remote control. Connect the LED to the Pin6 analog port and upload the following sketch.

LED control using Arduino PWM

For this lesson we will need the following details:

• Arduino Uno / Arduino Nano / Arduino Mega board;
• bread board;
• 1 LED and 1 220 Ohm resistor;
• male-male and male-female wires.

Scheme. Smooth blinking LED on Arduino

Sketch of smooth LED switching on from Arduino

#define LED_PIN 6 // set a name for Pin6 void setup() (pinMode(LED_PIN, OUTPUT); // initialize Pin6 as output) void loop () ( // smooth turning on of the LED // initial value on Pin6 i=0, if i<=255, то прибавляем к i единицу for (int i=0;i<=255;i++) { analogWrite (LED_PIN, i); delay (5); } //smooth fading of the LED // initial value on Pin6 i=255, if i>=255, then subtract one from i for (int i=255;i>=0;i--) ( analogWrite (LED_PIN, i); delay (5); // set a delay for the effect } }

Explanations for the code:

1. the for loop repeats as long as condition i is true<=255 или i>=0 ;
2. for a for loop, be sure to include the following values ​​in parentheses - (initialization; condition; increment);
3. The for loop construct must be placed between curly braces ( ) .

Recently I decided to put together a circuit that would allow me to smoothly light up any LED strip (whether in a car or at home). I didn’t reinvent the wheel, and decided to do a little Google it. When searching on almost every site, I found circuits where the LED load is severely limited by the capabilities of the circuit.

I wanted the circuit to just gradually increase the output voltage, for the diodes to light up smoothly, and for the circuit to be passive (it did not require additional power and would not consume current in standby mode) and would definitely be protected by a voltage stabilizer to increase the lifespan of my backlight .

And since I haven’t learned how to etch boards yet, I decided that first I need to master the simplest circuits and during installation use ready-made circuit boards, which, like the rest of the circuit components, can be purchased at any radio parts store.

In order to assemble a circuit for smooth ignition of LEDs with stabilization, I needed to purchase the following Components:

In general, a ready-made circuit board is a fairly convenient alternative to the so-called “LUT” method, where using the Sprint-Layout program, a printer and the same PCB, you can assemble almost any circuit. So, beginners should still first master a simpler option, which is much simpler and, most importantly, “forgiving of mistakes” and also does not require a soldering station.

Having simplified the original diagram a little, I decided to redraw it:

I know that on the diagrams the transistor and stabilizer are not indicated that way, but it’s easier for me, and it will be clearer for you. And if, like me, you managed to take care of stabilization, then you need an even simpler scheme:

The same thing, only without using the KREN8B stabilizer.

• R3 - 10K Ohm
• R2 - 51K Ohm
• R1 - from 50K to 100K Ohm (the resistance of this resistor can control the speed of LED ignition).
• C1 - from 200 to 400 μF (you can choose other containers, but you should not exceed 1000 μF).

At that time I needed two soft ignition boards:
- for the already made highlighting of the legs.
- for smooth ignition of the dashboard.

Since I had already taken care of stabilizing the LEDs illuminating my legs a long time ago, Krenka was no longer needed in the ignition circuit.

Smooth ignition scheme without stabilizer.

For such a circuit, I used only 1.5 sq cm of circuit board, which costs only 60 rubles.

Smooth ignition circuit with voltage stabilizer.

Dimensions 25 x 10 mm.

The advantages of this circuit are that the connected load depends only on the capabilities of the power supply (car battery), and on the IRF9540N field-effect transistor, which is very reliable (it makes it possible to connect a 140W load through itself at a current of up to 23A (information from the Internet). The circuit can withstand 10 meters of LED strip, but then the transistor will have to be cooled, fortunately in this design you can attach a radiator to the field device (which of course will lead to an increase in the circuit area).

During the first testing of the circuit, a short video was shot:

Initially, R1 was rated at 60K Ohm and I didn’t like the fact that ignition to full brightness took about 5-6 seconds. Subsequently, another 60K Ohm resistor was soldered to R1 and the ignition time decreased to 3 seconds, which was just right for illuminating the legs .

And since the ignition circuit for illuminating the legs had to be connected to a break in the main power circuit, without thinking long about how to insulate it, I simply stuffed it into a piece of the bicycle inner tube.

Having connected the smooth ignition circuit, I made another video:

That's all, I thank all those who were still able to read this post to the end. Of course, for some this will be a tough button accordion, but I hope there will be comrades who will be interested.

For beautiful illumination of individual car parts, backlights, instrument panels, side lights. It turns out to be a rather interesting effect, in which you turn off the power to an illuminated object, and it gradually fades out within 5 - 10 seconds...

How to implement smooth turning off of LEDs

To implement this, you and I will need the following components:

1. Actually the LED.
2. Capacitor (electrolytic, large capacity).
3. Diode.
4. Resistor if using 3.5 V LEDs.
5. Soldering iron, tin, flux.

Let's start with the object. Where can I put it? Well, it all depends on your imagination. Side lights, interior lights, instrument lighting - and many other places where you can insert a smoothly switching LED. I will soon implement a smooth switch-off of the interior lamp, that is, so that when the doors are closed it will remain on for some time. Also, if you make, in combination with them it will not turn out bad.

Well, let's begin. The purpose of all the elements, I think, is clear, but it wouldn’t hurt to repeat it. The LED is needed to emit light waves :). The capacitor is this element that stores the voltage that is consumed when the power is turned off. A diode is used to prevent current from flowing to other consumers, in other words, it acts as a kind of valve (it lets it go there, but not back).

Manufacturing of smoothly extinguishing LEDs

I’ll sketch out this intuitive diagram:

In the diagram we see that there is nothing complicated. So let's grab the soldering iron and go ahead. I will make a reservation that you need to find out how to accurately connect the components. Electrolytic capacitors have the ability to fly apart with a shot! So take a close look at the photo:

It is also important to connect the diode correctly:

Well, we seem to have sorted it out. As for the ratings of the parts, almost any diode will do, since the current is small. Capacitor – we select the capacitance individually; the larger the capacitance, the longer the LED lights up after the power is turned off. The voltage across the capacitor is at least 16V.

Brightness control for LED backlighting of car instruments.
Smooth LED ignition circuit.

Many car enthusiasts convert the backlighting of their car’s dashboard from conventional incandescent lamps to LEDs, and often, especially when using super-bright ones, the device shines like a Christmas tree and hurts the eyes with a bright glow, which requires the use of an additional device with which you can adjust the brightness level , as they say, to your taste. In general, there are two methods of regulation, this is analog regulation, which consists of changing the level of constant current of the LED, and PWM regulation, that is, periodically turning on and off the current through the LED for adjustable periods of time. With PWM control, the pulse frequency must be at least 200 Hz, otherwise the flickering of the LEDs will be noticeable to the eye. Below is a schematic diagram of the simplest block implemented on the NE555 timer chip, the domestic analogue of which is KR1006VI1; this chip generates pulse-width control signals.

The brightness level of the backlight is regulated by a variable resistor with a nominal value of 50 kOhm, that is, this resistor changes the duty cycle of the control pulses. An N-channel field-effect transistor IRFZ44N is used as a regulating element, which can be replaced, for example, with an IRF640 or similar.

There is probably no point in making a list of the elements used, there are not so many of them in the circuit, so let’s move on to looking at the printed circuit board.

The printed circuit board was developed in the Sprint Layout program; the type of board in this format looks like this:

Photo view of the PWM controller board LAY6 format:

Many people want to add a smooth ignition effect to the regulator circuit, and a simple circuit widely available on the Internet will help us with this:

On the printed circuit board we placed both of the above circuits, the regulator circuit and the smooth ignition circuit. LAY6 board format looks like this:

Photo view of LAY6 format:

Foil PCB for the board is single-sided, size 24 x 74 mm.

To establish the desired ignition and decay time, play with the values ​​of the resistors indicated on the printed circuit board with asterisks, this time also depends on the value of the electrolytic capacitance in the ignition circuit located above the LED output socket (With an increase in the value of the capacitor, the time will increase).

Please note that the smooth ignition circuit uses a P-channel MOSFET. The pinout of the transistors is shown below:

In addition to the article, we provide another example of a circuit with a brightness control and smooth ignition of LEDs on a car dashboard:

The size of the archive with article materials is 0.4 Mb.

Recently I decided to put together a circuit that would allow me to smoothly light up any LED strip (whether in a car or at home). I didn’t reinvent the wheel, and decided to Google a little. When searching on almost every site, I found circuits where the LED load is severely limited by the capabilities of the circuit.

I wanted the circuit to just gradually increase the output voltage, for the diodes to light up smoothly, and for the circuit to be passive (it did not require additional power and would not consume current in standby mode) and would definitely be protected by a voltage stabilizer to increase the lifespan of my backlight .

And since I haven’t learned how to etch boards yet, I decided that first I need to master the simplest circuits and during installation use ready-made circuit boards, which, like the rest of the circuit components, can be purchased at any radio parts store.

In order to assemble a circuit for smooth ignition of LEDs with stabilization, I needed to purchase the following components:

In general, a ready-made circuit board is a fairly convenient alternative to the so-called “LUT” method, where using the Sprint-Layout program, a printer and the same PCB, you can assemble almost any circuit. So, beginners should still first master a simpler option, which is much simpler and, most importantly, “forgiving of mistakes” and also does not require a soldering station.

Having simplified the original diagram a little, I decided to redraw it:

I know that on the diagrams the transistor and stabilizer are not indicated that way, but it’s easier for me, and it will be clearer for you. And if, like me, you managed to take care of stabilization, then you need an even simpler scheme:

The same thing, only without using the KREN8B stabilizer.

R3 - 10K Ohm
R2 - 51K Ohm
R1 - from 50K to 100K Ohm (the resistance of this resistor can control the speed of LED ignition).
C1 - from 200 to 400 μF (you can choose other containers, but you should not exceed 1000 μF).
At that time I needed two soft ignition boards:
- for the already made highlighting of the legs.
- for smooth ignition of the dashboard.

Since I had already taken care of stabilizing the LEDs illuminating my legs a long time ago, Krenka was no longer needed in the ignition circuit.

Smooth ignition scheme without stabilizer.

For such a circuit, I used only 1.5 sq cm of circuit board, which costs only 60 rubles.

Smooth ignition circuit with voltage stabilizer.

Dimensions 25 x 10 mm.

The advantages of this circuit are that the connected load depends only on the capabilities of the power supply (car battery), and on the IRF9540N field-effect transistor, which is very reliable (it makes it possible to connect a 140W load through itself at a current of up to 23A (information from the Internet). The circuit can withstand 10 meters of LED strip, but then the transistor will have to be cooled, fortunately in this design you can attach a radiator to the field device (which of course will lead to an increase in the circuit area).

During the first testing of the circuit, a short video was shot:

Initially, R1 was rated at 60K Ohm and I didn’t like the fact that ignition to full brightness took about 5-6 seconds. Subsequently, another 60K Ohm resistor was soldered to R1 and the ignition time decreased to 3 seconds, which was just right for illuminating the legs .

And since the ignition circuit for illuminating the legs had to be connected to a break in the main power circuit, without thinking long about how to insulate it, I simply stuffed it into a piece of the bicycle inner tube.