LED beacon circuit. How to make a flashing LED Simple DIY flashing light

We present to your attention probably the simplest, but most interesting LED flasher circuit. If you have a small Christmas tree made of shiny rain, then a bright 5-7 cd LED mounted in its base that not only lights up, but also blinks is a very simple and beautiful decoration for your workplace. The power supply of the circuit is 3-12 V, can be replaced by power from the USB port. The previous article was also about an LED flasher, but unlike it, this article will talk about a single LED flasher, which in no way narrows its scope, I would say even the opposite. Surely you have seen a winking green, red or blue light more than once, for example, in car alarm. Now you have the opportunity to assemble a simple LED flasher circuit. Below is a table with the parameters of the parts in the circuit for determining the flash frequency.

In addition to this application, you can use the LED flasher as a car alarm emulator. Installing a new car alarm is not a simple and troublesome task, but having the specified parts on hand can be quickly assembled LED flasher circuit and now your car is “protected” for the first time. At least from accidental hacking. Such a “car alarm” - an LED flashing in the crack of the dashboard will scare off inexperienced burglars, because this is the first sign of a working alarm? You never know where else you will need a flashing LED.

The frequency with which the LED lights up depends on the resistance of resistors R1 and R2 and the capacitance of capacitor C1. At the time of debugging, instead of resistors R1 and R2, you can use variable resistors of the corresponding ratings. To slightly simplify the selection of elements, the table below shows the ratings of the parts and the corresponding flash frequency.

If a flasher on an LED refuses to work at certain values, you must first of all pay attention to resistor R1, its resistance may be too low, and also to resistor R2, its resistance may be too high. The duration of the pulses themselves depends on resistor R2, and the duration of the pause between pulses depends on resistor R1.

The LED flasher circuit with minor modifications can become sound pulse generator. To do this, you will need to install a speaker with a resistance of up to 4 ohms in place of resistor R3. Replace LED HL1 with a jumper. Use a transistor of sufficient power as transistor VT2. In addition, it is necessary to select capacitor C1 of the required capacity. The choice is made as follows. Let's say we have elements with parameters from row 2 of the table. Pulse frequency 1Hz (60 pulses per minute). And we want to get sound with a frequency of 1000Hz. Therefore, it is necessary to reduce the capacitance of the capacitor by 1000 times. We get 10 µF / 1000 = 0.01 µF = 10 nF. In addition, you can play with decreasing the resistance of the resistors, but don’t get too carried away, you can burn the transistors.

One of our regular readers, especially for our site, suggested another option for a very simple LED flasher. Watch the video:

One of the simplest circuits in amateur radio electronics is an LED flasher on a single transistor. Its production can be done by any beginner who has a minimum soldering kit and half an hour of time.

Although the circuit under consideration is simple, it allows you to clearly see the avalanche breakdown of the transistor, as well as the operation of the electrolytic capacitor. Including, by selecting the capacitance, you can easily change the blinking frequency of the LED. You can also experiment with the input voltage (in small ranges), which also affects the operation of the product.

Design and principle of operation

The flasher consists of the following elements:

• power supply;
• resistance;
• capacitor;
• transistor;
• Light-emitting diode.

The scheme works on a very simple principle. In the first phase of the cycle, the transistor is “closed”, that is, it does not pass current from the power source. Accordingly, the LED does not light up.
The capacitor is located in the circuit before the closed transistor, therefore it accumulates electrical energy. This happens until the voltage at its terminals reaches a value sufficient to ensure the so-called avalanche breakdown.
In the second phase of the cycle, the energy accumulated in the capacitor “breaks through” the transistor, and current passes through the LED. It flashes for a short time and then goes out again as the transistor turns off again.
Then the flasher operates in cyclic mode and all processes are repeated.

Necessary materials and radio components

To assemble an LED flasher with your own hands, powered by a 12 V power source, you will need the following:

• soldering iron;
• rosin;
• solder;
• 1 kOhm resistor;
• capacitor with a capacity of 470-1000 μF at 16 V;
• transistor KT315 or its more modern analogue;
• classic LED;
• simple wire;
• 12V power supply;
• matchbox (optional).

The last component acts as a housing, although the circuit can be assembled without it. Alternatively, a circuit board can be used. The surface mounting described below is recommended for beginner radio amateurs. This assembly method allows you to quickly navigate the circuit and do everything right the first time.

Flasher assembly sequence

The manufacture of a 12 V LED flasher is carried out in the following sequence. First of all, all the above components, materials and tools are prepared.
For convenience, it is better to immediately fix the LED and power wires to the case. Next, a resistor should be soldered to the “+” terminal.

The free resistance leg is connected to the emitter of the transistor. If KT315 is placed with the marking down, then this conclusion will be on its extreme right. Next, the emitter of the transistor is connected to the positive terminal of the capacitor. You can determine it by the marking on the case - “minus” is indicated by a light stripe.
The next step is to connect the collector of the transistor to the positive terminal of the LED. KT315 has a leg in the middle. The "plus" of the LED can be determined visually. Inside the element there are two electrodes that differ in size. The one that is smaller will be positive.

Now it remains only to solder the negative lead of the LED to the corresponding conductor of the power supply. The "minus" of the capacitor is connected to the same line.
LED flasher on one transistor is ready. By applying power to it, you can see its operation according to the principle described above.
If there is a desire to reduce or increase the blinking frequency of the LED, then you can experiment with capacitors that have different capacitances. The principle is very simple - the larger the element’s capacity, the less often the LED will blink.

Any motorist knows that the use of special devices. purpose (for example, special signals such as SGU, strobe lights, etc.) is illegal and, when stopped by the police, you can be fined a tidy sum, plus confiscation of prohibited devices. Therefore, the article has been prepared for informational purposes - pay attention to this fact.

So, what is the difference between a strobe and a flasher? in theory, nothing, only the type of blinking of light-emitting diodes (or light bulbs). The flasher can be assembled in 5 minutes using a conventional multivibrator, but it will be a simple flasher, and not a strobe light, which are installed on government cars. services But for the viewer's information, a strobe is simply a device that produces bright flashes of light, so that a simple flasher can also be called a strobe.

How to assemble a strobe light, the operating principle of which is similar to the flashing lights that are on police cars? A simple multivibrator is not enough here, although our design in terms of complexity is not very different from a conventional multivibrator.

First we need a single-channel pulse generator, it can be anything, it can be based on a multivibrator or, even simpler, based on the legendary 555 timer

The timer is connected as a low-frequency generator of rectangular pulses; the frequency of these pulses can be adjusted with a variable resistor.

The output pulses from the microcircuit are sent to the input of the divider counter. And then the “reading” process begins. The counter outputs switch alternately, when one of the outputs is open, all others are closed.
Device diagram.

The outputs of the counter microcircuit are matched by diodes. The three outputs are connected as one, this is done in order to get a triple flash sequence for each LED. Since it is planned to connect powerful LEDs, the output was amplified with an additional transistor (in the case of each output).

Thus, we can connect even quite powerful loads, for example, incandescent lamps (12 Volts), but taking into account the fact that the main power will be dissipated on transistors and the latter will overheat quite strongly, so select transistors with a current of 10 Amperes or more and install them on the heat sink.

The diodes are the most common - 1n4148 low-power silicon rectifier diodes. The circuit works simply - the timer generates low-frequency pulses that are sent to the counter input. Each pulse will sequentially open and close the outputs from the counter, thus producing blinks, and diode isolation is made in order to obtain several blinks of one LED. For example, one of the LEDs will blink three times, then go out, then the same thing happens with the second.

The second circuit works on exactly the same principle, only here the LEDs are connected to all outputs of the microcircuit. This way we get a creeping line effect.

LEDs are the most common (just not the assembly), but if desired, you can control high-power loads by adding output transistors as an amplifying element, exactly as was done in the first design; below is a running line diagram.

In this circuit, in exactly the same way as in the first, you can adjust the switching frequency of the LEDs. This option is also a special signaling device; by amplifying the output and replacing the LEDs with super-bright ones, we get an illegal device, so I advise you to assemble it only for reference, at least not to use it in a car.

The PCB for the first circuit is available for download. Good luck!

Must be installed at a distance of at least 1200 mm. from the center of the lamp to the ground.

Beacons/light beams must be installed so that they are visible from any direction, at a reasonable distance.

The base plane of installed beacons/chandeliers must be parallel to the ground. At special signals installed on a flat roof and having a transverse axis of symmetry, the transverse axis of symmetry must coincide with the longitudinal axis of symmetry of the vehicle.

When installing beacons/light bars on a vehicle with a radio installed, the distance from the antenna must be at least 500mm.

Power cable special The signal must be routed separately, away from sensitive cables (radio, antenna, anti-lock braking system, brake system, etc.). If this is not possible, crossing the cables at right angles is allowed.

Attention - observe the power consumption mode. Select the correct cable and switching relay.

Before dismantling, disconnect the device from the power source.

Within 5 minutes after turning off the xenon beacon or light bar, there remains a danger of electric shock if you touch non-insulated elements. Do not touch the light bulb or glass tube with bare fingers. Do not overtighten the lens mounting screws.

Full installation instructions are included.

Fastening. Power supplies. Light

Beacon mounts may be different: bracket, magnet, bolts(there are fastenings with one bolt, some with three). Each type of fastening has a number of features. Installation on the bracket is very simple, but this type of mount is not recommended for use on large vehicles). In this case, it is recommended to use low profile flashing beacons. If a flashing beacon is used from time to time, they often opt for beacons with a magnetic mount. As a rule, these beacons are connected to the vehicle’s on-board system via the cigarette lighter. The downside of these beacons is the maximum speed limit (about 80 km/h). Although if you remember where these beacons are used, perhaps this is not a minus. Finally, you can install the flashing light using bolts (either 3 bolts at a 120 degree angle or 1 bolt in the center). To install these beacons, you need to make a hole in the roof of the car.

Beacon power supply- This is mainly direct current. Although the development of battery-powered beacons is almost complete.

Lighthouses can have three light sources: halogen lamp, xenon lamp And LED module. The price of the lighthouse and its service life depend on the light source. A halogen lamp generates a lot of heat during operation, and combined with high ambient temperatures, this can significantly shorten the period of operation of the beacon. Also, the power consumption of such a beacon is quite high compared to other types of sources. Another disadvantage of such a halogen light source is that the glare in the lighthouse is ensured by the constant rotation of the “curtain” around the lamp. Additional moving parts in the beacon will not increase its reliability. The xenon lamp does not have the disadvantages of the previous one. As a rule, these are generally pulsed beacons, the mode of which resembles the operating mode of a strobe light.

The operating voltage range is from 10 to 50 volts. In xenon beacons, instead of a lamp, a module with a printed circuit board is often installed, which is essentially disposable, which is its disadvantage. A beacon with an LED module closes the price chain. Diodes work for a very long time and despite the difference in price by 2, sometimes 3 times compared to halogen ones, they will last an order of magnitude longer. It is LED light sources that are used in explosion-proof beacons.

A good car alarm system, such as “Convoy”, “Sheriff”, “Alligator”, etc., costs a lot of money. But by making a simple device (see diagrams) based on a multivibrator, you can easily imitate it and thereby reduce the likelihood of car theft by approximately 40-50%, or even more. After all, it’s easier and safer for car thieves to “open” a car without signs of an alarm, and, unfortunately, there are plenty of them.

Typically, on cars with an activated (turned on) alarm system, a red, blue or green LED in the cabin flashes. It is usually installed somewhere on the front pillar of the passenger compartment. You can make such a device according to the following scheme.

The parts used in the simulator are not scarce, transistors can be used KT315, or KT815, KT972, electrolytic capacitors 50-100 uF 16 V, LED AL307 and several resistors of 10 and 0.5 kOhm. Such radio components can be easily found in old TVs, printers and other devices.

By changing the capacitance of the capacitors, you can change the pause or glow time of the LED (one is responsible for the pause, the second for the glow). The LEDs in this circuit light up smoothly and also go out smoothly. In my opinion, it is better to leave the glow time and pause symmetrical, i.e. put both capacitors at 100 uF.

The circuit starts working when powered with 3 volts, but it is better to power it from 9-12 V, then the LEDs will glow at their maximum and the simulator will be more noticeable.

You can power it from an on-board battery or a 9 V Krona, in the worst case, 2 batteries of 1.5 V. But! It is necessary to feed secretly, i.e. hide the wiring and board and bring out only the LED, and not from the cigarette lighter, like some. Otherwise, the thief will immediately understand that it is a dummy.

There are other options for blinkers, for example, based on an asymmetrical multivibrator. The circuit is built on transistors of different conductivities. Unlike the previous version, this circuit is powered by one or 2 AA batteries, i.e. 1.5 -3 V and lasts for about six months. But, if desired, the device can be powered through a voltage divider and from an on-board 12 V battery.

It works somewhat differently than the previous scheme; the LED lights up with a flash and quickly goes out. For me, the first option is more to my liking.

If the device is assembled according to the diagram, without errors, it works immediately and does not require any adjustment, except that, if desired, you can adjust the blinking frequency. The transistors in this circuit are silicon, KT315 and KT361 with any letter values. The regulation (generator frequency) can be changed within fairly large limits using R1 and C1.

But, during assembly, it is necessary to take into account that capacitor C1 in this circuit must necessarily be of the KM type, i.e., not electrolytic, not polar. The LED can be supplied in any color, but usually it is red or blue.

The circuit itself is economical and continues to operate when the voltage drops to 1 volt. Such a simulating device, due to its high efficiency, is often used by radio amateurs and others to “protect” apartments, country houses, garages, etc. For this purpose, there are more reliable options, for example, GSM alarm systems, in more detail.

There are other simulator circuits, they all work approximately the same, but the ones given here are tested and work 100%.

The above alarm simulator circuits are the so-called “passive” protection against theft or theft. Although these circuits are simple, they are worth the trouble of fiddling around and making the device, especially if your car is new and attractive, but you don’t want to spend money on a real alarm system, or don’t have the time or desire.