Automobile tachometer - a measuring device installed on a car and showing the frequency of revolution of the crankshaft in the engine. The unit of measurement is the number of revolutions per minute. The main function of the device is to monitor the level of crankshaft speed. This is necessary to prevent it from exceeding the maximum allowable value in order to optimize the operation of the motor.

The stable use of the tachometer during engine operation helps to reduce wear. Each approach of the arrow on the tachometer to the limit zone forces the driver to switch to a high gear. Tachometers - regulators of the engine at idle and while driving. As practice shows, a tachometer can be installed on a car of any brand, regardless of whether it was provided for in its equipment or not. And it does not matter which engine is installed on the car - gasoline or diesel. In case of failure, it can always be replaced with a new one.

On a car equipped with a standard ignition system, remote tachometers are installed in a viewing place, most conveniently near the dashboard. The black negative wire is connected to the car body. The red output serves as a power transmission line for the tachometer, it is connected to the ignition switch terminal, showing 12V at the moment of ignition itself. The third wire is attached to the coil terminal, to which the ignition distributor is also connected (if the ignition system is contact, if contactless, then a switch is connected to the terminal). This wire is responsible for the measured readings on the tachometer. If the tachometer system is provided with a scale illumination at night, it can be operated from the parking light switch.

The diesel system for installing a remote tachometer is also not a problem. In this case, the measuring output of the tachometer is connected on the generator to the terminal with the sign "W". If this terminal is missing, you can bring it out yourself using a tightly insulated wire. To begin with, you will have to remove the generator, and then also disassemble it. Thus, three wires will be visible extending from the winding and going to the built-in rectifier. You can connect a tachometer to any of them, having previously isolated and extended it to lead it out of the generator. At the end, assemble the generator in reverse order. It is imperative to ensure that the output wire does not touch moving parts.

Connecting a tachometer according to the specified system does not mean that it will accurately show the speed. Many of the latest tachometers count the pulses coming from the engine in different ways. For gasoline, one value is obtained, for diesel generators, another. Therefore, before you buy a tachometer for your car, you should find out if the device you have chosen is suitable for your model. But there are universal tachometers with a built-in switch that allows you to attach it without damage to different types of engine (from 2 to 8-cylinder gasoline and diesel).

You will need

• - remote tachometer;
• - new dashboard with built-in tachometer;
• - set of tools;
• - soldering iron;
• - cotton gloves.

Instruction

Read the manual for the repair and operation of your car. In it you can find instructions for installing and removing a standard tachometer on the injection model of your car.

Find out if there are regular dashboards with a tachometer for your car. If there are, then the most ideal and easiest option is to purchase and install such a board to replace the one that is installed in your car now.

To install a new dashboard with a built-in tachometer, it is necessary to partially or completely disassemble the torpedo. Each car model has its own features when removing the board. On some machines, it is necessary to disconnect the entire torpedo, while others just need to remove the protective visor above the dashboard, unscrew the screws that secure the fasteners.

It is necessary to connect a new dashboard according to the diagram, which is shown on the attached instructions. Do not forget to remove the minus terminal from the battery before installation.

Purchase and install a remote tachometer powered by a cigarette lighter. Such a device allows you to measure the number of revolutions by changing the current strength in the onboard power system. The remote tachometer, powered by the cigarette lighter, is very convenient, as it requires a minimum of effort to install.

However, it also has a small minus - the measurement error. This is due to the fact that each metal has its own resistance value.

Connect the tachometer directly to the cigarette lighter wires if you want to achieve the minimum error. To do this, remove the cigarette lighter socket from the connector and solder the wires from the tachometer to the wires coming from the car's power system, observing the color match.

For the most accurate measurement of engine speed, connect an external tachometer to the ignition coil. Remove the protective casing from the steering column and find the bundle of wires. Among them, separate those wires that go to the coil. There should be four in total. Solder one to the "plus", and the rest in accordance with the color of the wire itself.

Contact the service if you are not sure of your abilities. Install only the tachometer model recommended for use in your vehicle. The use of third-party instruments will, at best, lead to incorrect system performance.

www.kakprosto.ru

How to connect a tachometer to a diesel engine

The tachometer is a device that is actively used on gasoline and diesel vehicles. This device is used to measure the speed of rotation (revs) of the crankshaft or generator. Most modern vehicles are equipped with a standard tachometer directly from the factory.

The need to independently install a tachometer on a diesel engine may arise for various reasons. It should be noted that the connection scheme for a tachometer on a diesel engine is somewhat different from a similar solution for gasoline ICEs. In the process of choosing a tachometer for a diesel engine, this feature must be taken into account, since a tachometer for gasoline engines will not work on a diesel engine.

Where does the tachometer signal to the diesel engine

Today, for diesel engines, electronic, digital and analog tachometers are on sale, the connection diagram of which involves a number of features. The fact is that in the overwhelming majority of cases, the generator acts as the connection point for the tachometer for a diesel engine.

To implement the connection to the generator, you must have the tachometer itself, an insulated wire and the accompanying instructions for installing and operating an automobile tachometer.

Device connection

The principle of operation of an electronic tachometer is based on the reading of electrical impulses. In gasoline units, pulses are read, which are fed in a certain amount to the ignition coil. As for the diesel engine, the reading is carried out from a special terminal, which is located in the generator housing.

To connect a tachometer to a diesel engine, it is advisable to carry out work on a lift or use a viewing hole. At the initial stage, it is necessary to dismantle the protection from the generator, avoiding the ingress of dirt into the device. The next step is a visual inspection of the generator coil, on which there are several terminals. The tachometer contact (input wire) should be connected to the terminal that is usually marked with the letter "W".

Also, in some sources, it is recommended to additionally implement a contact closure that comes from the oil pump. This operation is performed in order for the tachometer to give the correct readings after installation, as well as to eliminate other problems. It is noted that otherwise, after the engine reaches a certain crankshaft speed, a warning lamp may falsely light on the instrument panel, indicating a critically low engine oil pressure in the engine lubrication system.

If the terminal marked “W” is not initially present on the generator, then you will need to independently remove a separate contact wire. A pre-prepared wire must be insulated with high quality. To facilitate access, the generator must be completely removed, as its partial disassembly will be required. After disassembly, wires (3 pieces) will become visible, going from the generator winding to the rectifier, which is also built into the device.

A prepared wire can be attached to any of these contacts, and then it can be removed outside the device case. Upon completion, the generator cover is put in place, the generator itself is mounted back. It is imperative to check that during the assembly process, the wire that is brought out does not come into contact with moving elements in the generator structure. Next, the tachometer wire is connected to the contact output from the generator in the same way as the connection if there is a terminal marked “W”. The remaining contacts of the tachometer are connected in accordance with the diagram, which is contained in the instructions for a particular device.

It is also worth considering that directly connecting the wire to the tachometer will lead to incorrect values. Additionally, a divider board is required, which will make the RPM readings correct.

krutimotor.ru

How to connect a tachometer, test and adjust it?

A tachometer is a device for measuring the rotational speed of engines, shafts, and other mechanisms. In transport technology, the tachometer has been used for more than a hundred years. As a rule, it is installed on the dashboard. The device indicates the rotational speed of the internal combustion engine during its operation. In modern cars equipped with electronic engine control systems, it is not always installed. However, the tachometer readings allow you to select the most suitable driving mode. In some cases, this allows you to save fuel or, conversely, switch to a more aggressive driving style. Therefore, experienced motorists, professional drivers often install dashboards with tachometers on their own.

Consider how to make an independent connection of the tachometer.

Tachometer

The principle of operation of the tachometer

Currently, tachometers are distinguished:

• Mechanical. Information about the engine speed is supplied to the mechanical tachometer using a rotating cable mechanically connected to the engine crankshaft. Now such devices are practically not used in cars;
• Electromechanical. The principle of operation of electromechanical tachometers is based on the conversion of electrical impulses from sensors installed on the engine or from other electronic devices. These signals are converted into magnetic impulses that deflect the pointer of the measuring device like a pointer voltmeter;
• Digital. Digital tachometers are used as part of modern computerized panels and are controlled by software and hardware. Self-installation of this type of tachometer is almost impossible.

Ways to turn on the tachometer

Information about the rotational speed of an internal combustion engine can be read from:

• generator;
• crankshaft speed sensor;
• camshaft speed sensor;
• ignition coil control pulse.

Alternators of some cars (for example, Volkswagen T4) have an additional AC voltage output, the frequency of which depends on the engine speed. In these machines, the signal to the tachometer is supplied from this point.

It is irrational to change the generator only to install a tachometer.

Tachometer connection diagram

The crankshaft and camshaft speed sensors work on the electromagnetic principle. Earlier vehicles had sensors using the Hall effect. In any case, the electrical impulse generated by these devices has an amplitude of not more than 5V, their internal resistance is not less than 200 ohms. In order to connect the tachometer to these sensors, an additional amplifier is required. It is most efficient to use a more powerful impulse coming to the ignition coil.

Ignition system of petrol engines

Control of engine ignition processes can be organized in several ways:

• Distributor with one ignition coil;
• Tramblerless with a dual (triple, quadruple, depending on the number of cylinders divided by 2) ignition coil;
• Individual (for each spark plug).

In all cases, a powerful pulse with an amplitude of 12V is supplied to the coil from a chopper (for cars up to the 90s), a transistor switch, or directly from the engine control unit. It is from this point that the signal to the tachometer should be taken.

Technical solution

Before connecting a tachometer, it is necessary to draw up an electrical connection diagram in order to mentally determine the start and end points of switching on, and trace the conductor. Any ignition coil has an output (terminal) +15 (ignition on), which is supplied with battery voltage when the key is turned to the first (for some cars - the second) position. In no case should you connect a tachometer to this point, the first time you turn it on, it may fail. High-voltage wires are also dangerous, even for humans. The signal input to which the tachometer is to be connected must be precisely defined. In older coils, it is marked with the letter "K", it is better to find the exact electrical circuit diagram of the car.

The next, more difficult task is the electrical connection of the nodes. As a conductor, you should take a stranded copper wire with a cross section of at least 2 sq. Mm. with PVC insulation.

The connection points of the wire to the ignition coil are cleaned, mechanically twisted, soldered and carefully insulated. Lay the wire along any electrical harnesses, using plastic zip ties, towards the bulkhead of the engine compartment near the dashboard. You can enter the conductor inside the passenger compartment next to any wiring harness. To do this, it is easier to use an elastic string. Finally, connect the conductor to the signal output of the tachometer. In some cars that provide modifications with and without a tachometer, you can simply change the dashboard, find a regular conductor and connect it to the ignition coil.

Test, tachometer adjustment

If the car is equipped with a distributorless or individual ignition system, the tachometer can be connected to any coil. In this case, the readings of the engine speed (rpm) will be inadequate, since a pulse is supplied to the trampled ignition every cycle, an individual one - four times less often. However, it is possible to calibrate the measuring scale in a new way.

At the first stage of testing, the engine is started, the system performance is checked (arrow deflection at idle). As a rule, the speed in this mode is in the range of 800 - 1000 rpm.

Next, adjust the reading level. If the tachometer needle deviates slightly, you can connect an additional capacitor with a capacity of about 1 microfarad between the signal wire and the vehicle ground. On the contrary, if the arrow goes off scale, include a variable resistance of about 1 kOhm in the signal circuit break and scale the signal.

The next step is sea trials. On a running engine, they reach the maximum speed. The tachometer needle should not go into the red zone. Otherwise, the adjustment is carried out again. Before starting operation, once again check the reliability of connections and insulation. And remember, additional hardware brings new challenges.

autodont.ru

Do-it-yourself tachometer installation: affordable instructions

A car enthusiast who takes care of his car should have, among other devices, a tachometer that helps to properly operate the car. If there is no standard device, then it should be installed. The article provides their types, gives instructions on how to properly connect a tachometer to a diesel engine and to an engine with gasoline.

The tachometer informs about the number of revolutions of the crankshaft, helping to determine at what point it is best to shift gears. This makes it possible to increase the service life of the power unit and operate it correctly, since the power and traction characteristics of the engine depend on the crankshaft speed. In addition, it can be used to fine-tune the carburetor and other important devices at idle.

This meter can be analog, which is a display with arrows and numbers. When the arrow approaches the red line, the driver must shift to a higher gear. On a digital device, information for the driver is displayed on a small screen (the author of the video is Armadil).

Conventionally, devices can be divided into two types:

1. Established. They are installed at the factory that manufactures the vehicle. They put it on the torpedo.
2. Remote. They are an alternative option if a factory device is not available. Remote devices have more accurate readings, so they can be used to check the correctness of regular readings. Sometimes they are installed as tuning.

1. Regular device on the top five 2. Analog device for cars 3. Remote car devices

The tachometer can be installed both on a gasoline engine and on a diesel unit.

Connection to a petrol engine

The connection of the device is different on an injection engine and with a carburetor. With an injector, it is connected to the ECU controller. In this case, the "mass" is diverted to the body, and the positive wire must be connected to the positive ignition terminal.

The device has two outputs: one goes to the crankshaft position sensor, and the other to the computer. Thus, it will read the number of revolutions from the controller of the control unit. Below is a diagram of connecting a tachometer with BSZ.

Scheme with contactless SZ

The following is an instruction on how to connect an electronic tachometer to a gasoline power unit:

1. First, depending on the type of device, you need to install it at the place where it will be located.
2. Next, the installed tachometer should be connected. The negative wire, usually black, is connected to ground.
3. The red wire should be connected to the plus of the ignition switch, which is supplied with 12 V when the ignition system (SZ) is operating.
4. The third wire can have any color - this is the input of the device. It is connected depending on the SZ. If the SZ is contact, then the device is connected to the distributor breaker, in the case of a non-contact SZ, it must be connected to the voltage switch.
5. If the car is equipped with a backlight, then the device must be connected to the switch dimensions of the car.

Scheme for contact SZ

Connecting the device to a diesel engine

Diesel owners should know how to install a tachometer on a diesel, as its connection has nuances. To do this, you need to understand the principle of its work. It reads, in the case of a gasoline power unit, the pulses supplied to the ignition coil, and in the case of a diesel engine, from the “W” output of the generator.

It is better to install the device on a diesel engine by placing the car on a viewing hole or a lift. Connecting an electronic tachometer is carried out in stages. The first step is to remove the protective cover, avoiding contamination.

After disassembly, it is necessary to connect one of the three wires that go from the winding to the built-in rectifier with a wire prepared in advance. The connection point must be insulated and the wire must be brought out. Next, the generator should be assembled in the reverse order. The output wire from the generator must be connected to the meter.

For accurate readings, it is necessary to close the contact that comes from the oil pump.

Rear view of the instrument

Checking the performance of the tachometer

With the installation of the tachometer, everything is clear, thanks to the instructions above. It remains to find out the causes of meter malfunctions. Sometimes drivers can observe a situation where the arrow starts to twitch from side to side.

There may be several reasons for the failure:

• during prolonged operation of the motor, the resulting vibrations can damage the device;
• wiring faults: tips may come off, contacts may oxidize, insulation may be broken.

These damages can be identified by visual inspection and repaired. If the sensor is faulty, it must be replaced.

Video "Connecting a tachometer"

This video demonstrates how to connect a tachometer yourself (the author of the video is Dmitry Kolesnik).

A car enthusiast who takes care of his car should have, among other devices, a tachometer that helps to properly operate the car. If there is no standard device, then it should be installed. The article provides their types, gives instructions on how to properly connect to an engine with gasoline.

[ Hide ]

Varieties of tachometers

The tachometer informs about the number of revolutions of the crankshaft, helping to determine at what point it is best to shift gears. This makes it possible to increase the service life of the power unit and operate it correctly, since the power and traction characteristics of the engine depend on the crankshaft speed. In addition, it can be used to fine-tune the carburetor and other important devices at idle.

This meter can be analog, which is a display with arrows and numbers. When the arrow approaches the red line, the driver must shift to a higher gear. On a digital device, information for the driver is displayed on a small screen (the author of the video is Armadil).

Conventionally, devices can be divided into two types:

1. Established. They are installed at the factory that manufactures the vehicle. They put it on the torpedo.
2. Remote. They are an alternative option if a factory device is not available. Remote devices have more accurate readings, so they can be used to check the correctness of regular readings. Sometimes they are installed as tuning.

The tachometer can be installed both on a gasoline engine and on a diesel unit.

Connection to a petrol engine

The connection of the device is different on an injection engine and with a carburetor. With an injector, it is connected to the ECU controller. In this case, the "mass" is diverted to the body, and the positive wire must be connected to the positive ignition terminal.

The device has two outputs: one goes to the crankshaft position sensor, and the other to the computer. Thus, it will read the number of revolutions from the controller of the control unit. Below is a diagram of connecting a tachometer with BSZ.

The following is an instruction on how to connect an electronic tachometer to a gasoline power unit:

1. First, depending on the type of device, you need to install it at the place where it will be located.
2. Next, the installed tachometer should be connected. The negative wire, usually black, is connected to ground.
3. The red wire should be connected to the plus of the ignition switch, which is supplied with 12 V when the ignition system (SZ) is operating.
4. The third wire can have any color - this is the input of the device. It is connected depending on the SZ. If the SZ is contact, then the device is connected to the distributor breaker, in the case of a non-contact SZ, it must be connected to the voltage switch.
5. If the car is equipped with a backlight, then the device must be connected to the switch dimensions of the car.

Connecting the device to a diesel engine

Diesel owners should know how to install a tachometer on a diesel, as its connection has nuances. To do this, you need to understand the principle of its work. It reads, in the case of a gasoline power unit, the pulses supplied to the ignition coil, and in the case of a diesel engine, from the “W” output of the generator.

It is better to install the device on a diesel engine by placing the car on a viewing hole or a lift. Connecting an electronic tachometer is carried out in stages. The first step is to remove the protective cover, avoiding contamination.

After disassembly, it is necessary to connect one of the three wires that go from the winding to the built-in rectifier with a wire prepared in advance. The connection point must be insulated and the wire must be brought out. Next, the generator should be assembled in the reverse order. The output wire from the generator must be connected to the meter.

For accurate readings, it is necessary to close the contact that comes from the oil pump.

Checking the performance of the tachometer

With the installation of the tachometer, everything is clear, thanks to the instructions above. It remains to find out the causes of meter malfunctions. Sometimes drivers can observe a situation where the arrow starts to twitch from side to side.

There may be several reasons for the failure:

• during prolonged operation of the motor, the resulting vibrations can damage the device;
• wiring faults: tips may come off, contacts may oxidize, insulation may be broken.

These damages can be identified by visual inspection and repaired. If the sensor is faulty, it must be replaced.

Video "Connecting a tachometer"

This video demonstrates how to connect a tachometer yourself (the author of the video is Dmitry Kolesnik).

The standard instrument torpedo VAZ 2105 is not equipped with a tachometer. This unit allows drivers to monitor the speed of the crankshaft of the vehicle's engine. Experienced auto mechanics know how to put a tachometer on a VAZ 2105.

Part Selection Rules

Essential car tool

You can install this unit with your own hands. This will require the following tools and materials:

• screwdrivers,
• wiring diagram,
• keys,
• insulating tape,
• wires.

First you need to find out the principle of operation of the unit in question. The pulses read by this device enter the ignition coil, displaying information on the screen. Auto mechanics recommend buying an electronic tachometer. When choosing this device, one should take into account the structural features of the VAZ 2105. Otherwise, the tachometer will show revolutions with a slight error. You can install a universal unit with switches. To do this, connect it to any type of engine.

In the selection process, one should also take into account the fact that there are pointer and electronic tachometers. You can install a tachometer on the VAZ 2105 of the first type with a tuner. The Balsat TX-319t model belongs to the second type. It is a microprocessor device, the main task of which is to monitor the operation of the "five" engine. If necessary, the driver can choose the most suitable mode. Before you figure out how to install a tachometer on a VAZ 2105, you need to consider the capabilities of the car:

1. crankshaft speed measurement for 2-6 and 8-cylinder engines,
2. availability of hours
3. the ability to remember the maximum and minimum temperatures,
4. the presence of a stopwatch,
5. the ability to measure the acceleration of the crankshaft.

The installation of an electronic tachometer provides for self-tuning of the backlight. The advantages of the Balsat TX-319t auto mechanics include the presence of a standby mode. This feature significantly reduces energy costs.

Installing the instrument

How to connect a tachometer of this type is of interest to many car owners of the VAZ 2105. To begin with, the mounting location is selected. Then the "minus" wire is connected to the vehicle body. The plus wire is connected to the appropriate ignition terminal. It has a voltage of 12 watts.

The backlight allows you to see the speed at any time of the day, so auto mechanics recommend installing just such units. Before starting work, you need to figure out how to connect a tachometer of this type. For this, an appropriate scheme is used. The backlight wires are connected to the size switch. If the auto is of the injection type, then the device is connected to the controller of the electronic motor control system. In this case, reading is carried out from the last element. Installing a tachometer from another car is prohibited, as difficulties may arise in the operation of the mounted unit.

Many motorists are well aware of why and for what purpose engineers came up with a tachometer in cars. Some do not look at it at all, and on some cars its presence is not provided. Is there an electronic tachometer for these cars?

What does it represent?

Before we talk about electronics, let's see what this device is for in general.

So, this is a special device that is installed on cars to control the crankshaft speed. So, this device shows the driver at what frequency the motor rotates. This is necessary so that the driver does not exceed the permissible speed.

main function

The tachometer helps inexperienced drivers who still cannot determine the speed by the sound of the unit, to choose the right gear. Riding in the right gear allows you not only to significantly increase the resources of the power unit components, but also save fuel. When the arrow of the device enters the red zone, it is recommended to shift to a higher gear. Also, this device is used to adjust carburetors both at idle and while driving.

Operating principle

The tachometer registers the number of pulses that are supplied from the sensors. Pauses between impulses and the order in which they arrive are also taken into account. The counting process can be carried out using both forward and reverse directions. Indicators are often translated into a certain value. This value can be any indicator. Most of these devices can be reset. As for the accuracy of the readings, it is rather conditional. The best quality electronic tachometer has an accuracy of about 100 rpm.

Digital tachometer device

If we consider this device, then this device consists of:

• central processor;
• 8 or more bit ADC;
• coolant temperature sensor;
• display;
• optocoupler, which is used for diagnostics;
• reset block.

Electronic switch devices

The electronic tachometer is in most cases made in display format. The readings are displayed on this screen.

These are the revolutions of the crankshaft. Especially these devices are convenient in the arrow version. Switch equipment can most often be seen on dashboards. Drivers find it very convenient, as the signals from the sensors are transmitted to the arrow. Scientists have proven that the brain perceives information better from the arrow, in contrast to the numbers on the display.

We assemble an electronic tachometer with our own hands

Why buy when you can assemble everything yourself? It's not that expensive and quite interesting. For assembly, there are several options for devices. These devices are assembled on the basis of contact or non-contact sensors. In non-contact systems of the optical type, laser or infrared beams are used to register pulses. The time of one revolution is calculated. Let's see how to build your own optical registration device using an Arduino-type microcontroller.

Electronic tachometer circuit on Arduino

To assemble the device, you will, of course, need an Arduino microcontroller. If it is not there, then any other controller with similar characteristics will do, but then you will need to additionally assemble the programmer. Also, for this circuit, resistors of 33 kOhm, 270 Ohm, 10 kOhm are needed in the form of a potentiometer. You can also purchase a blue LED, an infrared LED and a photodiode. Next, find the DSW display and shift register chip labeled 74HC595. It uses an optical sensor and the principle of reflecting rays. With this system, you don't have to worry about how thick the rotor should be, and the number of rotor blades won't change the performance. The sensor will be able to accurately read the revolutions.

Assembling the sensor

First of all, to create a sensor, you need an infrared diode and our photodiode. In the first step, sand the diodes until they are flat. Then it is recommended to fold a strip of paper in the form of a rectangular tube.

Further on the scheme

Resistors and their ratings may vary slightly. It depends on the diodes. A variable resistor makes it possible to change the sensitivity level of the resulting sensor. So, the "ground" is connected to a 33 kΩ resistor and to a variable resistor, and that, in turn, is connected to a wire that needs to be installed in front of the potentiometer. The minus of the LED is connected through the remaining resistor to the ground, and the plus goes to the Arduino. So, it turned out three conclusions - ground, plus and a signal wire. This circuit uses an 8-bit shift register and display. In the case, it is desirable to think over the recesses for the indicator. Now a 270 ohm resistor is soldered to the LED and then installed in pin 12 of the microcontroller. Now the electronic tachometer is ready. You can do its programming and calibration. The program for "Arduino" can be found on automotive resources.

Another homemade tachometer

In order to measure the number of revolutions, as we already know, the pulse count of the interrupter is used or the voltage from the spark plugs. The frequency of these pulses is linearly related to the speed of the motor. You can also try to organize an inductive connection with such a circuit, which will be demonstrated in this device. The single vibrator marked LM 555 is used as the basis for this option.

The element is launched due to impulses from candles that are induced in the coil. The input contact is used either for setting or for signaling from the interrupter. For an ordinary four-cylinder unit, the speed of which is 3000 rpm, the frequency is 100 Hz. For 1500 rpm - 50 Hz. This makes it possible to easily calibrate the device in terms of frequency. The pulses received from the third output of the microcircuit are fed to the dial indicator. In this circuit, the author uses a milliammeter. The indicator will show the voltage in this network. Since the duration of the pulses at the output of the microcircuit is approximately the same, the voltage is proportional to the frequency with which sparks are formed. So, the scale of the measuring device can be redrawn by calibration. The head from an old cassette recorder is excellent as a coil. It should be located near the high voltage coil. To protect the microcircuit, you can use a 12 V diode.

Tachometer for motorcycles

How to put an electronic tachometer on a motorcycle? Here, the owners of motor vehicles have a choice: either purchase ready-made equipment, or make it yourself. Suppose that there is a motorcycle, there is a device for controlling speed. But how to connect an electronic tachometer? The device TX-193 from the six for these purposes is best suited for mounting on domestic brands of motorcycles.

The device has extraordinary accuracy, low weight, economical power consumption, as well as stable operation in vibration conditions. I must say that this model cannot even be compared with any tachometers for motorcycles. The process of connecting the device to two-cylinder motorcycles with a starter and battery, as well as single-channel ignition, is no different from the process of connecting the same device to a VAZ. The input of the device is connected to the output of the primary winding of the ignition coil. The device can be powered by a battery. For this, the unit has the appropriate wires. It is then recommended to install a switch in the positive cable. This is useful when the technique is at a standstill. This way you can save battery power.

If the motorcycle is not domestic and there is still the same electronic tachometer, the connection diagram will change slightly. In this case, you will have to power through the ignition switch. There are special contacts for these purposes. If the motorcycle does not have a starter, then the battery should be connected to the rectifier output. And from the battery it is already possible to supply power directly to the tachometer through the switch. If there is no rectifier, you need to buy one. If there is no battery, you can put it. The easiest option is a power source from a UPS or an old flashlight. If you connect a measuring device directly to the generator coil, then it will burn out. To avoid this, you can ask a neighbor radio amateur to make a voltage regulator on thyristors.

If the engine has three cylinders, then signals from two coils are input here. There are also technical possibilities for installing a tachometer on six-cylinder motorcycles, but this already requires the purchase of branded equipment.

Installing a tachometer on VAZ cars

You can purchase a freelance electronic tachometer (VAZ 2109 is not equipped with these necessary devices on a regular basis) and enjoy life. Modern devices are also multifunctional. On many of them, the car enthusiast will additionally find an alarm clock and many other useful things.

It is worth noting that these devices differ in the type of engine power. For gasoline engines, the principle of operation is one, for diesel engines - completely different.

Gasoline devices also have differences in the number of cylinders

So everything is bought. Now decide where you will install the electronics. Many put it on the dashboard, others mount it near the ignition switch. However, it is best if the electronic tachometer is installed in a place where it will not spoil the appearance of the panel.

For fixing, the best friend of a motorist will help - double-sided tape. This universal tool saves in a variety of situations.

Do-it-yourself device connection

Not everyone understands electronics, but it is still desirable to be able to connect a measuring device. This will not cause difficulties, because there are only three wires. The first thing to do is take the wire from the tachometer to the engine compartment. The easiest way to do this is through the hole in the speedometer cable. Next you need a piece of wire. It should be about one meter long, thin and hard. At one end, secure the wire from the device with electrical tape. Try to work carefully. Gently insert the other end of the wire into the holes in the cable and push. Connecting an electronic tachometer can be done as follows. The positive wire is connected to the ignition coil (pin B). Connect the signal wire to contact K of the same coil. Minus connect to ground. Work as carefully as possible, the wires are very thin and very unreliable.

Now it remains to start the car and test everything. That's all. Now you know how to connect an electronic tachometer, and you can even assemble the device yourself if you wish. It won't take you much time and effort.