DIY trip computer. How to make and install an on-board computer with your own hands. Purpose of control buttons

The on-board car computer or the “brains” of the car is the most important element for controlling and monitoring the performance of all the main components of the vehicle. BC is installed on all modern cars today. You can learn more about the principle of operation and types from this material.

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Description of the on-board computer

What is an on-board computer in a car and what tasks does it perform? First, let's look at some theoretical points. The BC is an electronic unit that allows you to react and control various processes in the operation of different car systems. That is, thanks to the BC, the driver will always be able to receive data on the operation of certain components. We figured out what an on-board computer is, now we’ll tell you about its purpose.

What the on-board computer shows:

• the device demonstrates gasoline consumption in different driving modes;
• allows you to control the injectors, as well as the vehicle ignition system;
• monitors the operation of the transmission;
• can control various additional systems via two-way communication, for example, a rear view camera, etc.;
• allows you to determine the level of engine fluid pressure and antifreeze temperature;
• regulates the voltage level in the car’s electrical circuit, monitors the battery charge;
• if the vehicle is equipped with a climate control system, then the BC controls it;
• One of the main options - the on-board computer for the car allows, if necessary, to read error codes and show them on the display so that the driver can decipher them and find out where to look for a breakdown.

Principle of operation

The principle of operation of an automobile BC for carburetor engines or injection options is not particularly complicated. The device is connected to a chain of controllers and regulators, reads the necessary data, and then processes the received information. Special software is used for processing. For example, if the BC receives data on fuel consumption according to the scheme, then the software will allow you to calculate the possible mileage with the remaining amount of gasoline.

All data is displayed on a screen installed in the vehicle interior. The display itself can be digital, monochrome, color, or four or three digits. As practice shows, a 2-inch diagonal monochrome screen is quite enough to show the driver more than ten parameters. More modern versions of bookmakers today are equipped with a high-precision liquid crystal screen.

Kinds

Today there are several types of BC:

1. Universal option Such a device combines various options and gives the car owner the opportunity not only to drive the car, but also to surf the Internet. The main purpose of such a device is to increase comfort for the car owner while driving. Typically, a universal on-board computer has a screen with a diagonal of 6-14 inches; newer models can be connected to a keyboard. It should be noted that in their design, such BCs are very similar to ordinary computer PCs, but one of the features of the devices is the low degree of integration with the car’s electrical system.
2. Route. The trip on-board computer allows you to determine the driving parameters of the car, and it does not have to be connected via GPS to the satellite. However, newer models are equipped with GPS receivers in any case. Using such a device, the driver will be able to determine the average speed of the car, fuel consumption, remaining distance to a particular point, mileage traveled, etc. In addition, depending on the model that you install in your car, the device may have a function for calculating fuel consumption during emergency braking or rapid acceleration. Typically, BCs of this type are installed in the control panel.
3. Manager and service bookmaker. The purpose of such computers is to detect breakdowns of the main components of the vehicle and warn the car owner about this. As a rule, such a BC is an integral part of the machine control system, but depending on the model, it can also be an independent device with extensive functionality. When checking a car, all combinations of errors are stored in the device’s memory and will remain there until the error is corrected and the memory is reset (the author of the video is the AvtoGSM channel).

Bookmaker setup

Making an on-board computer with your own hands is a difficult task to accomplish at home. To make a device, you will need many different elements, including a display, a chip, buttons, etc. It is impossible to make a computer on your own without experience in assembling such devices, so if you want the device to work correctly, then it is better to order this procedure or buy a new computer.

If you decide to install an on-board computer for carburetor or injection engines on your car, then you need to know how to configure the device correctly:

1. If necessary, you can always activate the automatic configuration option - then the device itself will accept the necessary configuration.
2. If this option does not suit you, then go to the settings menu - find the desired block and select it. It should be noted that in this case the bookmaker must be configured as the main device. One of the important roles in setting is determined by the choice of mode, thanks to which fuel costs will be recorded.
3. When setting this parameter, you have several options. One of them is a linear dependence, in which case the parameter will always depend on the control unit. If you decide to configure it manually, then first you will need to make a table on fuel consumption. Taking this information into account, the bookmaker will carry out calculations and display the corresponding parameters on the screen.
4. In addition, you will need to determine the parameters that the screen will begin to display; depending on the model, their number may vary. Separately, we should highlight the parameter responsible for the activation temperature of the engine cooling fan.

Price issue

The minimum cost of a bookmaker from the Multitronics company will be around 130 rubles. More expensive options can cost 7,500 rubles.

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Video “How to make a bookmaker with your own hands”

Detailed instructions for making the circuit are presented in the video (author - libral1973 channel).

Technology does not stand still and today car enthusiasts are offered many different options for improving their “iron horses”. One of these is Arduino. This device is a tool used for designing electronic devices. In the case of a car, the design is usually done on the windshield. How to make an on-board computer using Arduino and how to configure it correctly - read this article.

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Ideas for a car based on a small board with a small processor - Arduino

Computers have long been a part of our lives. The Arduino hardware platform is one of the latest open source developments that is built on a conventional printed circuit. We will tell you more about how to make different devices for cars using such a board.

BC

Using an Arduino board, you can build a car on-board computer that can:

• calculate fuel consumption;
• display information about the antifreeze temperature;
• calculate the speed of movement, as well as the distance of the trip;
• remove spent fuel over a certain mileage;
• determine the motor speed, etc. (the author of the video is the Arduino Tech PTZ channel).

In addition to the Arduino device, you will also need an LCD module, a Bluetooth adapter NS-05, as well as an ELM327 scanner and a 10 kOhm resistor device. Of course, it is necessary to prepare the sound indicator, installation wires and the device body itself.

The assembly procedure is as follows:

1. First we set up the Bluetooth adapter. You need to solder wires to the pins of the device - to the two lower and upper contacts.
2. The module itself is connected to the board for configuration; to do this, you need to open the Arduino IDE 1.0.6 program or any other version, then upload the sketch to the circuit via the USB output.
3. When the download is complete, you need to go to the Tools menu - Port Monitor and set the speed to 9600.
4. Then a circuit is assembled with a board, an adapter and a pre-prepared display. First, connect the Bluetooth adapter.
5. After this, a display is added to the circuit. You will find a more detailed description of the connection in the photo below.
6. A 10K resistor element is used to control the brightness and contrast of the display. Therefore, when you first connect, you may notice that there is no image, if this is the case, then you just need to adjust it by turning the resistor.
7. Next, an additional key is connected, which will perform the function of switching screens with information. One contact from the button goes to the GND element, the second to pin 10. To connect the beeper, the positive contact is connected to pin 13, and the negative contact to GND.
8. Then, using the same Arduino IDE 1.0.6 software, you need to upload the sketch. Now all you have to do is set up the on-board computer and connect it to the car.

Photo gallery “BC connection diagram”

GPS tracker

To build an Arduino-based GPS tracker, you will need:

• the board itself, the process is described using the example of the Mega 2560 model;
• GSM/GPRS module, which will be used to transfer data to the server;
• as well as an Arduino GPS receiver, in the example we will look at the SKM53 model (the author of the video about making a tracker using the SIM 808 board as an example - Alex Vas channel).

How to connect the circuit:

1. First, the module is connected to the main board; the default baud rate is 115200.
2. After connecting, you need to turn on the device and set the same speed for all ports - both serial and software.
3. The GSM transmitter is connected to pins 7 and 8 on the main chip.
4. Then the module is configured by entering commands. We will not describe all the commands; they can be found on the Internet without any problems. Let's consider only the most basic ones. AT+SAPBR=3,1, “CONTYPE”, “GPRS” - the command determines the connection type, in this case it is GPRS. AT+SAPBR=3,1,“APN”,“internet.***.ru”, where *** is the address of the mobile network operator that will be used. AT+HTTPINIT - this command initializes HTTP.
5. One nuance should be noted - when writing the server component of the interface, it is advisable to provide for receiving and outputting data for several adapters. You need to set the switch to three positions, this will make it possible to receive data from eight cars.
6. Then the sketch is written on the microcircuit. The sketch itself can also be found on the Internet; it is not necessary to write it. Please note that if two active serial ports are used, this may lead to errors in the transmission and sending of information.

Parktronic

To build a parking sensor, you will need the following components:

• the chip itself;
• ultrasonic device, in this case it is the HC-SR04 rangefinder:
• six LED elements;
• six resistor elements with a resistance of 220 Ohms;
• male-to-male connecting wires;
• piezodynamic element;
• layout diagram for assembly.

The build procedure is as follows:

1. To begin with, you need to install LED elements prepared in advance on the breadboard circuit. The negative contact of all LEDs will be common. The short contact - the cathode - should be connected to the negative bus, which is located on the breadboard.
2. To the longer contacts of the diodes, that is, the anodes, you need to connect 200 Ohm resistor elements; if you do not use them, this will lead to the diodes burning out.
3. An ultrasonic device is installed on the central part. There are four pins on this controller. Vcc is the five volt power pin, Echo is the output pin, Trig is the input, and GND is ground.
4. After the rangefinder is installed, wiring should be connected to its outputs. In particular, the Echo pin is connected to output 13, Trig - to pin 12. GND, accordingly, needs to be connected to the ground, which is available on the controller circuit, and the remaining Vcc output is connected to the 5-volt power supply on the Arduino board.
5. After completing these steps, you need to connect the wiring to the contacts of the resistor elements. They are also connected in series to pins on the board - pins 2 to 7 are used.
6. The next step will be to connect a piezo beeper, which will warn the driver when approaching an obstacle. The negative output, as an option, can be combined with the negative contact of a previously installed rangefinder. As for the positive contact, it connects to pin number 11 on the chip.
7. In order for the device to ultimately operate in normal mode, you will additionally need to write and then load the program code into the board. In this code, it is necessary to accurately indicate the distance, when approaching which the diode elements will light up and the buzzer will be activated. Moreover, the tone of the beeper should be different so that the driver can know when approaching an obstacle will be critical. The code itself is either written independently, or a ready-made version is taken from the Internet. There are a lot of sketch options, you just need to choose the most suitable one for your device (the author of the video is the Arduino Prom channel).

Conclusion

As you can see, the Arduino microboard is a universal option with which you can create many different devices. In addition to the devices described above, you can also build a speedometer that will display speed information directly on the windshield, a start-stop button, and even an alarm for the vehicle. In general, there are a lot of options, if you approach the issue of making a homemade gadget correctly, then you will succeed.

Of course, to do this you must have knowledge in the field of electronics and electrical engineering, while minimal skills will most likely not be enough. When making devices, you will have to make your own decisions, which may not be available on the Internet. Therefore, be prepared that the assembly process may take quite a long time.

Video “How to build a control system for an electric stove motor?”

From the video below you can learn how to set up climate control by modifying the heating system regulator using the example of a VAZ 2115 car (the author of the video is Ivan Nikulshin).

Modern cars are increasingly equipped with an on-board computer for recording instantaneous and average consumption. Being the owner of a Fiat Marea 1.9JTD, this function was not provided for. Factory devices refused to work or displayed scant and unimportant information.

I am a supporter of simplicity and reliability of my developments. This is completely demonstrated by the operation of the assembled device.

Homemade on-board computer (BC) via the K-Line interface for Italian cars. Tested for JTD Euro 2 and 3 (CF2, CF3). The circuit for matching the levels of the microcontroller with the K-line was taken from the ELM327 diagnostic adapter; commands (PIDs) for polling the car ECU were scanned along the K-line when running the Multiecuscan diagnostic software. We also studied the documentation [ JSC AvtoVAZ General Development Department Electronics and Electrical Equipment Design Department], [ISO/WD 14230-1 - Road Vehicles - Diagnostic Systems - Keyword Protocol 2000 - Physical layer].
ISO14230 protocol. To receive/transmit via the K-line, the PIC16F628 hardware USART interface was used. But since the transmitter pin (TX) does not have the function of the inverse operating mode required by the circuit conditions, the adjacent pin was used. Which operates programmatically in the TX transmitter mode, inverting its state.
The circuit is based on a 16x2 HD44780 indicator (power pinout may differ), a PIC16F628A controller and some passive smd elements (size 1206 and 805), the rating is not critical. Transistors can be MMBT2222 SOT-23 (2N2222). Krenka for 5V in the layout with the heatsink up for a circuit with a dip PIC. Depending on the LSD backlight (>20mA), a small heatsink may be required for cranking. Chain R10 and D16 perform the protective function of the circuit. The board itself fits into the dimensions and is glued to the back of the display.

When connecting the circuit to a car, connect the K-line last, do not allow the K-line of the BC to be shorted to positive!

The software part of the circuit begins with initializing the LCD and connecting to the car's ECU. For Euro type ECUs 2 and 3, the addressing of connection to the unit is different; the selection is made by holding the UP button until the desired type CF2 or CF3 appears. If the connection to the ECU is successful, the LCD backlight will turn on. Next, read the HW and SW numbers of the ECU for JTD. And go to the first menu, 4 parameters (instantaneous and average flow rate, engine speed and temperature), other menus can have 2 or 3 parameters. Jump by
menu with the UP or Down key (press indication is the first segment shaded). You can save the current menu (from 0 to 12) as the starting menu when you turn on the on-board computer - by holding UP for a long time (more than 2 seconds).

In menu 13 - reading errors, displaying the number of errors and up to 4 codes (P*** together), deleting errors - by holding UP for a long time.
In 14 menus (instantaneous consumption and total amount of gas oil) - you can change the number of cylinders in the car (4 or 5) to correctly calculate fuel consumption - by holding UP for a long time.
In menu 15, reset the average speed and average flow, and also adjust the LCD backlight - by holding UP for a long time.
LCD backlight control is a chain: pin13 through T2 - standard brightness; and pin3 through R12 - reduced backlight brightness.

In the update of the circuit, archive No. 2, the menus are shifted and 15 menus are allocated for continuously adjusting the brightness of the screen backlight (PWM). When you hold the button for a long time, the brightness increases smoothly from 0 to 255 and so on in a circle. When the button is released, the brightness value is saved in non-volatile memory. In this case, it is possible to lose communication with the ECU, because the poll is interrupted.
Fuel consumption is calculated based on the readings of the total amount of gas oil, revolutions and speed of the car. And the calculation occurs when the consumption menu is active. Instantaneous consumption is displayed in liters/hour at speeds up to 10 km/h, and above - in liters per 100 km. By de-energizing the BC, the average flow rate is reset and =0. Formula for calculating consumption =...Liters*100/...km. When the distance traveled is zero, the average consumption tends to infinity. As you move and the distance traveled increases, the average will approach the instantaneous flow rate.
The menu includes a set of the following parameters: engine speed, current speed, cruise control speed, engine temperature, fuel and air temperature, heating of glow plugs and fuel, total amount of gas oil, air consumption, fuel pressure and its regulator, boost pressure and its regulator; calculation of instantaneous and average flow rate, and average speed; read/delete auto errors.

The message "Error K-Lines" indicates that the K-line is shorted to negative, the circuit power is below 9V, or the circuit is faulty, in particular, transistor T1 burnt out when the K-line is shorted to positive.
In the VAZ version, all data is read directly from the ECU in one frame, including consumption in l/100 km and l/h, according to the documentation. For VAZ (Lada) BC works with the January-... block.

List of radioelements

Any digital device seemed like a computer to us - even a primitive tachometer with two numbers. How many computers are installed in an average car today? Things are already approaching a hundred... Moreover, the capabilities of a modern smartphone significantly exceed the potential of the computer on the Curiosity rover, which is only five years old.

What can't standard on-board computers do? Bend your fingers. They will never tell you error codes for engine, automatic transmission, door or window control systems. They rarely show engine temperature, average speed, travel time or acceleration dynamics to hundreds, and also do not like to remember errors that occur. In addition, many drivers need hazard warning lights that monitor temperature, engine speed, and speed.

The owners have their own requests - to take at least the fuel consumption of two types. Some people need automatic turning on of headlights based on a signal from a speed sensor or connection of parking sensors with adjustable sensitivity. In some cases, it may be useful to force the cooling fan on. Some people want to more accurately adjust the fuel level sensor in the tank. Various reminders will help those who are forgetful - warning about the side lights not being turned off, about ice on the road, or the need to undergo regular maintenance. Many people love simple talking toys (“Hello, master!”). Extreme enthusiasts may need a wheel slip indicator. And there is also such a function as a taximeter...

We decided to test ones suitable for budget cars. The capabilities of the devices selected for the study are different, but all the more interesting.

• trip parameters: travel time, mileage, current and average speed, instantaneous and average consumption, remaining fuel in the tank, ambient temperature, cost of the trip;
• current engine operating parameters: pressure in the intake manifold, fuel pressure in the line, injection duration, air pressure at the compressor outlet, mass air flow, oxygen sensor voltage, crankshaft speed, throttle position, gas pedal position, instantaneous fuel consumption, calculated engine load, coolant temperature;
• error parameters: ECU errors, reset and error recording;
• parking parameters (some devices turn their screen into a display of full-fledged parking sensors).

And most devices also provide a voice warning when the controlled parameters leave the specified range.

It seemed to us that the most interesting option in the presented computer company was the Multitronics MPC‑800. Mainly because such a device, which has decent “brains,” does not disfigure the interior of the car, since it is hidden somewhere inside, assigning “representative” functions to the owner’s smartphone. For many, this may be the deciding factor when choosing a device.