A flashing LED can be implemented and used in several ways, which determines its further scope of application. Circuits can consist of several diodes, transistors, be connected to different power sources, even batteries, and blink differently. You can assemble most of them with your own hands, but sometimes you need to adjust the theoretical basis.
One of the simplest ways to implement blinking LED indicators can successfully simulate a car alarm. For premium cars this is not very relevant, but for less elite vehicles, the total cost of which does not cover the installation of an expensive warning system, such a scheme will be just right. In this case, an LED flasher would be the best option.
Flashing LED as an alarm
Buy a blinking diode for a car and save yourself from painstakingly sitting through processing the board. This is not always true, but in this case it is very appropriate. It is important to understand why the LED is blinking.
In appearance, such a blinking indicator cannot be distinguished from a regular LED, which glows constantly. When voltage is applied, it begins to blink a couple of times per second. Having a multimeter will also help you identify semiconductor devices. In the forward direction, the blinking diode shows a small resistance, and in the reverse direction - an LED with a normal voltage drop.
A little about the flashing LEDs themselves
The LED flashing is based on a small chip, which consists of a high-frequency master oscillator. The latter works in conjunction with a logical divider, making it possible to obtain the required 1-3 Hz instead of high frequency values.
To implement a low-frequency oscillator, it is necessary to use a capacitor with a large capacitance. If you decide to assemble the circuit yourself, it would be very problematic to use a semiconductor with a large area. Why - it simply won’t fit in the LED housing.
The semiconductor base contains not only a generator and a divider, but also an electronic key and a protector diode. Flashing LEDs with a supply voltage of 3-12V are also equipped with a limiting resistor, but low-voltage LEDs do not require it.
The main purpose of the protector diode is to prevent damage to the microcircuit if its power supply is reversed.
When applying voltage to the vehicle network, the value of the current-limiting resistor should be selected from the range of 3-5 kOhm. Having connected the LED with your own hands, you can note that it consumes current not only when flickering, but also in the slots.
DIY alarm assembly
Having decided how flashing LEDs are designed, how they work, and why they flash, you can proceed directly to installation.
For assembly you will need 2 flexible stranded wires of small diameter. It is preferable to choose cables of different colors in order to be able to distinguish them when connecting to car wiring.
Once the resistor and both wires are secured, you can place the circuit in a thick polymer tube. The final stage of installing the alarm yourself is connecting the wires to the “+” and “-” power circuits of the car. If everything flashes as it should, the LED flasher can be considered successful.
Assembling circuits with your own hands based on LEDs is very popular among car enthusiasts. Why? Diodes provide enormous opportunities for tuning. Replacement of any lighting, interior lighting and much more.
Hello again everyone! In this article I will tell novice radio amateurs about how to make a simple flasher with just one cheapest transistor. Of course, you can find ready-made ones on sale, but they are not available in all cities, the frequency of their flashes is not regulated, and the supply voltage is quite limited. It is often easier not to go shopping and not wait for weeks for an order from the Internet (when you need to have a flashing light here and now), but to assemble it in a couple of minutes using the simplest scheme. To make the structure we will need:
1 . Transistor type KT315 (It doesn’t matter whether it has the letters b, c, d - any will do).
2 . Electrolytic capacitor voltage of at least 16 volts, and a capacity of 1000 microfarads - 3000 microfarads (The lower the capacity, the faster the LED flashes).
3 . Resistor 1 kOhm, set the power as you like.
4 . Light-emitting diode(Any color except white).
5
. Two wires(Preferably stranded).
First, the LED flasher circuit itself. Now let's start making it. It can be done as an option on a printed circuit board, or it can also be mounted, it looks something like this:
We solder the transistor, then the electrolytic capacitor, in my case it is 2200 microfarads. Don't forget that electrolytes have polarity.
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 values. 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:
The master reveals the secret of a simple LED flasher with sound, built with his own hands using electronics from a broken electronic-mechanical watch.
How to make a flasher with sound with your own hands
To operate, you need a mechanism from an electronic-mechanical clock with a ticking motion. A broken mechanism will also work, since the malfunction is 99% due to damage to the mechanics. Please note that a smooth-running mechanism is not suitable for crafts. It is easy to distinguish the mechanisms; if you look carefully at the photographs, 3 large gears are clearly visible under the body of the ticking clock, but under the body of the smooth running mechanism there are four gears. The process of removing the electronics board is clearly shown in the video. Next, work with the circuit must be carried out according to the following instructions:
1. We remove all the mechanics with our own hands and put them aside. The wires from the coil can be broken.
2. Mark the polarity of the power terminals on the board. Carefully pry up the electronics board and remove it.
Ticking mechanism3. Tin the contact pads with solder. This must be done quickly and carefully. When overheated, the pads easily peel off and then break off.
4. Solder the power conductors. The clock chip will operate when supplied with a voltage of 1.5 to 5 Volts.
5. Solder a TR1203 type sound emitter and any LED to the board, depending on what purposes you want to use the resulting circuit. Watch the video and photo of the flasher circuit. The flasher will work and should blink the LED every second, and then beep. This is perhaps what distinguishes the circuit from all similar flashing lights. You can connect two LEDs to the circuit and they will flash sequentially and alternately, why not a ready-made controller for flying models of replica airplanes?
Flasher circuitThis 12-volt LED flasher allows you to create the effect of chaotic flashes of each of the 6 LEDs. The operating principle is based on avalanche breakdown of the p-n junction.
Description of LED flasher operation
Let us describe the operation of the circuit on one block; the remaining five work on a similar principle. When supply voltage is applied through resistor R1, capacitor C1 begins to charge and therefore the voltage across it begins to increase. While it is charging, nothing happens.
After the voltage at the terminals of the capacitor reaches 11...12 volts, an avalanche breakdown of the p-n junction of the transistor occurs, its conductivity increases and, as a result, the LED begins to glow due to the energy of the discharging capacitor C1.
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When the voltage across the capacitor drops below 9...10 volts, the transistor junction closes and the whole process repeats from the beginning. The remaining five blocks of the circuit also operate at approximately the same frequency, but the actual frequency is slightly different from each other due to the tolerances of the radio components.
You can use arbitrary radio components in the design. It should be noted that if the supply voltage is less than 12 volts, the circuit will not work, since avalanche breakdown of the transistor will not occur and the generator will not work. A special feature of this type of generator is its dependence on the supply voltage. The higher the voltage, the higher the oscillation frequency. The upper power level is limited by the characteristics of capacitors and current-limiting resistors.
The values of resistors and capacitors determine the operating frequency of each individual generator. Resistors protect transistors from destruction during an avalanche breakdown. The resistance of the resistors should not be greatly underestimated, as this can lead to failure of the transistors. The same thing can happen if the capacitor capacitances are increased too much. In this case, it is advisable to connect additional resistance in series with the LED.
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