DIY radio circuits for a car. Car homemade products

If you have a subwoofer lying around somewhere, then it wouldn’t be a bad idea to assemble a simple subwoofer amplifier for it using a tda7377

Car radio from a module from aliexpress

Do-it-yourself lithium battery 12 Volt

Many people use the popular 12V 7.2Ah lead-acid battery in some devices. This battery can be found in many devices, from children's electric vehicles to UPSs, or systems to maintain the voltage of critical devices in the event of a power failure. Why is he so popular? Price is its main advantage and, probably, the only one.

connecting a voltmeter with aliexpress

A voltmeter with REM came to me by mail from China. First of all, I checked its operation at home using a computer power supply. And by the way, I’ll tell you something else. some people wrote to me that REM does not work on them, and that the voltmeter works constantly, even when the power supply is turned off. At first I thought so too.

Do-it-yourself booster for starting a car

As winter approaches, a common problem for drivers is that the battery may not always start the car, it is either seized, and the battery itself does not work very well in cold weather.

A good solution would also be to create DIY booster.

In simple terms, this is the same external battery (power bank) as for a phone, only this time for our car.

Charging for a car battery from modules with Ali

With the onset of the cold season, car enthusiasts are increasingly faced with how to charge their car battery.

In this article, we won’t need much, because we’ll collect DIY charger made from modules from the well-known site - Aliexpress.

How to connect a consumer with a 12V supply voltage to a 24V network

how to connect a consumer with a 12V supply voltage to a 24V network

(voltage converter 24v-12v)

It is known that in some cars, the on-board network is not 12 Volts, which is most common, but 24 Volt.

And here some difficulties arise, but how to connect the same radar detector or video recorder or another consumer operating on 12 Volts.

To do this, it would be good to assemble a converter for a car that will convert our 24 Volts to 12 Volts. And you can install a cigarette lighter on these 12 Volts, and then turn on our consumers there.

Subwoofer box filler

What filler to choose for the subwoofer housing.

When creating a subwoofer with your own hands, you should also consider what filler to choose for the box, and also take into account such rules as:

1) The material of the box should be as solid as possible. (Tap on 8K plywood and then on 20K plywood and you will understand what I mean)

2) The box must be as strong as possible. (joints and connections must be stronger than the material itself)

Every car owner tries to improve his car to the best of his ability. Moreover, the older the car, the stronger the desire to make it a supercar, equipped with the latest achievements of science and technology.

Everything is good, but in moderation. You understand this when you see a not-so-new penny, hung with flashing lights, bumpers and sophisticated security systems. We will not suggest equipping the Tavria with an on-board computer or installing an automatic stability control system on the nine.

Homemade electronics in cars

We will imagine what we can do useful for our car if we have at least a little understanding of electronics and know how to hold a soldering iron. Useful electronics for a car, installed and tested yourself, can be useful not only for us, so we offer a small digest of simple devices that simplify the life of a motorist.

Down with the catalyst

When removing the catalyst yourself, you may encounter some difficulties. On some car models, it is not possible to remove the primary catalyst, or you do not want to reflash the ECU. In this case, there is a simple device that will mislead the cunning ECU so that when the catalyst is removed, the warning lamp for a malfunction in the engine management system will not light up.

This simplest device is adjusted to the nominal performance of catalysts on all Mitsubishi, Chevrolet Lacetti, Nissan Premiere. For other cars, you just need to select the desired rating of radio components using the oscillogram. There is nothing complicated about this - there are a lot of reference books.
Here is a schematic diagram of the device and its appearance.

Parts ratings:

  • 150 kOhm resistor;
  • 1 µF capacitor.

After soldering the entire structure, we treat it with insulating varnish and encase it in a thermal casing. The control lamp will no longer remind you of itself.

A very useful and simple device. To make it, we only need an old piezo lighter. When a spark plug is broken into the body, a spark appears on the contacts periodically, and this manifests itself in unstable operation of the motor. There are special devices for checking the spark plug, but they are not in the arsenal; there is always a replacement.

We take out the piezoelectric element from the lighter, lengthen the wires and insulate them so that there is no electric shock. Let's install the device on the spark plug as shown in the figure, press the button and carefully look at the contacts. If the spark jumps, it means the spark plug is 100% working.

The simplest charger

Surely every motorist with experience has encountered a situation when he needs to recharge the battery, but there is no charger at hand. Such a charger, the circuit of which we offer, can easily be carried with you in the trunk. It can be useful on long trips, where there is no access to a full charger. The main thing is that there is an outlet.

Its scheme is extremely simple. It is made on a transformerless basis, so the device is compact and lightweight. The device does not heat up and can work for as long as desired. It has one drawback - it does not have galvanic isolation. That is, the current from the network goes directly to the battery through the capacitor unit.

To convert alternating current into direct current, a rectifier is used - a diode bridge. It is quite possible to find it ready-made, or you can assemble it yourself. The bridge must be designed for a voltage of at least 400 V with a current of at least 3 A. The capacitor unit must show a total capacitance of 8 μF.

In order for the circuit to discharge after switching off, a 220-810 kOhm resistor is installed at the output. Instead of a set of capacitors, you can use one, but capacious one - 10 µF. Battery clamps can be placed on the output wires for ease of use. The circuit is very compact and will fit into any case. This is not an ideal charger, but as a last resort it can come in handy more than once.

For a skilled soldering iron, there is always work to be done in creating pleasant little things for comfort, for safety, for creating additional lighting. The main thing is to know that this is a necessity. And then any device or device will be a useful and pleasant addition to the design of the car.

A selection of original and interesting circuit solutions and improvements for various types of cars.



Automatic car charger- The circuit turns on the battery for charging when its voltage drops to a certain level and turns it off when it reaches the maximum.
Charger for a car using an integrated circuit LM7815- The basis of the circuit is the LM7815 integrated circuit with a protection system and analog indicator circuits. A voltmeter and an ammeter added to the circuit as indicators provide monitoring of current and voltage while the battery is charging.
Automatic voltage polarity switch for charger - designed for charging twelve-volt car batteries. Its main feature is that it allows connecting a battery with any polarity.
Automatic charger for car lead-acid batteries
Charger for powerful car batteries- based on the IR2153 chip, this is a self-clocked half-bridge driver, which is quite often used in industrial ballasts for fluorescent lamps


Engine overheat sensor. In order not to wait for the moment when the water in the radiator turns into steam, you can use the design on the DS1821 thermostat
Ice sensor As soon as the air temperature drops to 4 degrees Celsius, the LED mounted on the vehicle's dashboard will begin to blink; as the temperature drops further, the LED blinks at a higher frequency. And if the temperature drops to - 1 degree or lower, the LED will light continuously until - 6 degrees, and then the device automatically turns off.
Seat belt sensor If you drive without wearing seat belts, you can get injured in an accident or face a fine. The radio amateur has special developments in his arsenal that signal to the driver that the seat belt is not fastened
Radiator water level indicator. A device that signals a decrease in water level, which will inevitably lead to overheating of the motor.
Voltage indicator in the vehicle's on-board network Most cars do not have a device from which the driver can judge the voltage of the on-board network. The voltage of the vehicle's on-board network varies widely, depending on the operating mode of the power supply system.
Scheme of pre-sleep driver status indicator As is known, up to 25-30% of transport accidents are caused by drivers falling asleep at the wheel. To assess the psychophysiological state of the driver while driving, telemetric systems have been developed to monitor the blinking frequency of his eyelids, register biopotential, galvanic skin response, and motor activity. All of the above methods have not found wide application in practice due to their complexity, high cost, and the need to fix various sensors on the driver’s skin


Amateur radio selection on the topic of lighting in the car interior, as well as homemade designs from rear license plate illumination to replacing light bulbs in the instrument panel: LED turn signal, automatic anti-glare flashlight, Low beam diagrams, designs and accessories for headlights, Stop signal, its purpose and modifications, Delay diagram for turning on and off the light in the car interior, Running lights automatic control circuit on a microcontroller, etc.

Making a neutral sensor. Many car enthusiasts know that installing a car alarm with auto start on a car with a manual transmission is quite difficult, and switching the alarm to the “automatic” mode can get an unpleasant result. But, to solve these problems, you can make the autostart operation safer by installing a neutral sensor from the reed switch. Let us remind you that with an autostart with a manual transmission, the logical neutral position of the car, arming the car and locking the doors can only be done with the engine running and the handbrake raised. If these conditions are not met, then autostart is not possible.
Anti-theft device simulator simulates engine malfunctions of your car
Remote anti-theft device using infrared rays. Schemes of remote security devices for cars using IR rays, which use information coding, are considered.
Recommendations for installing car alarms What can be done to prevent car theft? Of course, install an anti-theft system. There are many different types of alarm devices available today. Many companies and installation stations can offer the car owner a number of ways to protect the car from theft. A good alarm system does not guarantee complete safety. A competent, and sometimes non-standard, alarm installation is also required. A qualified installer knows the most common methods used by hijackers and uses this knowledge during installation
Simple starter blocking circuit consists of just one resistor and optocoupler.
Diagram of a simple bicycle anti-theft system This design for a bicycle will work if you change its position or if you touch it. The alarm sound lasts 30 seconds, and after a few seconds it repeats, and so on until the bicycle anti-theft device is turned off.
Wireless car alarm- blocks the car engine using any mobile phone or smartphone


Articles about making tools and devices for servicing and repairing cars and their main components with your own hands: Car battery maintenance; diagrams of stroboscopes-tachometers; Car paint thickness gauge; Homemade regrower for cutting tread and other original designs.

We bring to the attention of radio amateurs a circuit of an electronic ground switch that does not have mechanical contacts and is therefore more reliable and durable. In addition, this device can also be used as an anti-theft device.

Car diagrams. Parktronic on a digital chip

Parktronic is a special auxiliary device that provides additional convenience, especially for a novice car enthusiast, when parking by calculating the distance to the obstacles closest to the car and signaling the approach to them with sound and visual signs. All parking sensors work like a radar, that is, they emit ultrasonic waves with special ultrasonic sensors and analyze the sound signal reflected from obstacles

It's the 21st century, and car speedometers in most cars are still analog, processing signals coming from a conventional speed sensor. Let's correct this misunderstanding, Nav to help, a simple speedometer circuit on a microcontroller for making it yourself

Of course, this is not a professional device, but its modest capabilities will allow you to identify the degree of alcohol concentration for the driver’s self-control in order to prevent trouble on the road.

I think every car enthusiast will not refuse to have an additional service connector in the car, adapted for USB or miniUSB. Such adapters will help out in many situations, for example, powering PC peripherals, charging mobile phones or smartphones, event video recorders, and anything that is powered from the USB bus.

Motion sensors (MS) can be used not only for their intended purpose to turn on lights or as an element of a security alarm, but also in cars. For example, it will scare away a cat that decided to bask under the soot of your car, thereby saving its life, and saving you from the work of cleaning your engine from the remains of the poor animal. After all, the infrared DD will react to any moving biological object that has a “thermal” background.



There are many components in a car that are quite difficult to control when they are turned on and in good working order, and for these purposes an audible alarm is ideal; in addition, its use while reversing informs surrounding pedestrians and other drivers about the vehicle moving backwards, which is especially important for large trucks

I suggest for your consideration that you familiarize yourself with a simple diagram of a car window closer. It performs the role of raising the windows at the moment when the car is set to the security alarm. The operation of the window lift device is stopped as a result of an increase in the flowing current in the load at the moment the windows are fully raised.

Automotive electric fuel pump device, principle of operation and repair. As an example, let's consider the design and principle of operation of the submersible electric fuel pump series 0580254 from BOSCH, which is used in all modifications of the K-Jefronic fuel injection system.

Car alarm It is designed to simulate a car horn, and is made using composite transistors and thyristors

Many people have portable receivers and tape recorders with a 9-volt Krona battery. On the road, they can be conveniently powered from a car battery without using up the resource of expensive batteries. It is impossible to connect such radio equipment directly to the battery, since its voltage can vary from 10 to 15 V. In addition, when the engine is running, impulse noise appears in the vehicle’s on-board network

A selection of simple diagrams for car enthusiasts: Sound alarm anti-sleep, ice alarms, Installation for cleaning crankcase gases, Device for quickly starting the engine in any frost, Compressometer, Anti-radar, Aerodynamic nozzle on the exhaust pipe and other designs

The collection of electrical circuits for cars is a very large selection.

The microcontroller circuits discussed below display readings from a 40L fuel sensor on a two-digit digital indicator with a common anad. The structures are powered from the vehicle's on-board network. The original car sensor in the tank is connected to the “in” input.

Probably all drivers have at least once forgotten to turn off the direction indicators after performing a maneuver? Standard clicks from the front panel are not always clearly audible, especially if there is music playing in the cabin, so I suggest adding a simple turn signal signal circuit to your car with your own hands.

The cigarette lighter is one of the few car features that has retained its original design for more than 70 years. As a result of this, both vintage cars and the most modern models use the same design. Of course, in the old days this device was used only for one function, although now in the modern “information world” it performs different functions, for example a connector for charging various digital gadgets or even starting a car.

Amateur radio circuits for turn signals are designed to work only with LEDs in your car's brake lights; if you are still using regular bulbs, you can easily replicate the design of the turn signal. Simple development" Brake lights" - a homemade time relay will turn off the latter if they are on for more than 40-60 seconds, and turn signal relay upgrade 495.3747 will allow the introduction of LEDs instead of incandescent lamps into the standard equipment of VAZ or GAZ.

The proposed first option for upgrading the car windshield wiper relay has higher operational reliability and can provide dynamic engine braking. No modifications to the standard electrical equipment circuit are required. Quite simple options for upgrading the windshield wiper relay will allow you not to be distracted by turning the wipers on and off. In addition, many older cars have a simple windshield wiper motor speed control - two positions "fast and slow" - no major modification is simply necessary. Install a humidity sensor and water drops falling on it will automatically trigger the circuit.

A car monitor with rear view cameras is a very important element in your car, because in modern urban realities you need to be a parking master to find a place to park the car. An example of installing a monitor in a car visor is clearly shown, which makes the image optimally positioned for the driver’s eyes.

Nowadays, the issue of accounting and saving energy resources, including fuel for vehicles, is more pressing than ever. Of the wide variety of devices that take into account fuel consumption, the most widely used are devices with a sensor recording element in the form of an impeller. Sensors with a different measurement principle, although they have sufficient accuracy, are difficult to manufacture and have disadvantages. Practice has shown that sensors with an impeller, made with the necessary and sufficient accuracy, can operate for years without requiring maintenance, with a registration error below the tolerance for this type of device

The ignition system is a set of various automotive instruments and devices that generate an electric spark to ignite the air-fuel mixture in the cylinders of an internal combustion engine when the ignition system key is turned. On this page you can find various ignition connection diagrams for VAZ cars. As well as homemade amateur radio versions of the electronic ignition circuit

It has the following advantages: the spark power is increased, the breaker contacts do not burn; no resistor is needed in the ignition coil circuit; when the ignition is on, but the engine is not started, the circuit smoothly without a spark turns off

In the Soviet automobile industry, the RS57 type turn signal interrupter was of an electromagnetic operating principle and was used to ensure the flashing of warning lights, which makes the turn signal more visible and noticeable to other road users. The turn signal switch is connected in series to the turn signal circuit. Within the framework of the article, we will consider options for replacing this electromagnetic device with its electronic analogues.

Probably every car enthusiast forgot in the warm season to close the windows in the car, so that this does not happen again, I suggest putting together a circuit designed to automatically close all the windows in the car when the alarm is set. Let's consider several possible options for implementing the design, from simple circuits with relays to automatic window lift control on a microcontroller.


Every driver of a truck or bus with an on-board voltage of 24 volts has encountered the problem of connecting a 12 volt consumer. This article provides a solution to this problem.

In all modern cars, when the engine temperature reaches a critical point, the radiator cooling fan is activated. But there are a lot of negative effects of a sudden start, which over time affects the electrics of the vehicle. This article describes a diagram of an option for replacing the cooling fan soft start relay.

Carburetor economizer device

Carburetors were installed on cars for many years until they gradually made way for various fuel injection systems. But the automobile age of Russian cars is long, and we still have to deal with vehicles that still have a carburetor. Well, as you know, its normal operation is ensured by several devices, the main one being a fuel economizer. This is exactly what we will talk about, and also consider the diagram of the forced idle economizer system for VAZ cars

A car starter is a device that allows the engine to start after turning in any weather conditions. Almost all starters, in their essence, are conventional short-term electric motors, but of high power. The starting cycle of a typical device consists of three attempts with a 30 second interval between them. Since the car has a single source of electricity (the battery), the engineers chose a DC electric motor for the starters.

Every car owner who has driven a budget car knows how long it takes to wait for heat to come from the engine when it warms up in the winter, especially if you live in the northern part of the largest country in the world. It takes about 30 minutes to reach a comfortable temperature, and this happens every morning. The best idea to solve this problem, in my opinion, is to heat the car interior with a fan heater. An old toaster and a faulty computer power supply helped bring the idea to life.

In winter, many Russian drivers begin to experience a time when driving a car requires a preheated engine. A car antifreeze heating circuit helps solve this problem. The first one discussed is quite simple to repeat.

A heated steering wheel, along with heated seats, mirrors, and windows, is not a luxury these days, but an indicator of the level that a person lives in a civilized country. All of the above parameters in a personal car are very convenient, and help the driver to concentrate only on driving the vehicle, and not on his frozen fingers.

This design is designed to generate a sound signal when trucks and buses move backwards, and in automatic mode a sound signal begins to be generated to warn of danger.

The main advantage of the second battery is that the accumulated energy is consumed through an additional battery, and the first one is in reserve, that is, you don’t have to worry about starting the car after a picnic far from civilization. Many foreign cars already have a second battery under the hood. Their only drawback is the parallel connection of 2 batteries

This amateur radio design is suitable for charging most smartphones and tablets from 5 volts, even when the ignition is turned off. Or it will allow you to power the DVR for 40 minutes, while the car is waiting for its owner in the parking lot. The basis of the circuit is the AVR Tiny13 microcontroller, the firmware is attached to it.