Trip computer MK-21093. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Automobile. Electronic devices

Comments on the article

If you install this small device on the dashboard of your car, it will be able to control and display on a digital display at your request up to seven very important parameters of movement on the highway.

The version of the device described here is designed for installation in "eights" and "nines" of the Volga Automobile Plant. To work on other vehicles, the device will need to make more or less changes. We intend to tell about the finalization of the trip computer MK-21093 for installation on such vehicles as Moskvich, Volga, the first VAZ models, in subsequent publications.

The trip computer MK-21093, produced by the Kursk OJSC "Schetmash", is designed for installation on carbureted cars VAZ-2108 and VAZ-2109. For the new models VAZ-2114 and VAZ-2115, the enterprise produces a modification of this computer - MK-2114 - in the same dimensions, but with slightly different display elements and a large number of functions performed. There is also a variant MK-2112 of a different design for installation on cars VAZ-2110, VAZ-2111, VAZ-2112.

The trip computer MK-21093 measures and displays seven parameters of the car's movement. At each moment, the scoreboard shows the value of one parameter. Select one or another parameter of interest by pressing the buttons. The list of controlled parameters and the limits of their values ​​are presented in Table 1.

Table 1

The operating voltage range of the computer supply voltage is 10,8 ... 15 V. To store information in the memory node, it should not be less than 6 V. At a supply voltage of 13,5 V, the device consumes no more than 20 mA when the indication is off, and does not more than 300 mA - when enabled.

The night illumination circuit of the control buttons consumes a current of about 100 mA.

The time of periodic updating of information on the scoreboard (except for time parameters) is 1,7 s. The computer is operational at an ambient temperature of -40 to +60 ° C. When the car's external lighting is turned on, the brightness of the computer's digital display decreases by 15 ... 20 times and the night illumination of the characters turns on.

The value of the basic error of the computer at a supply voltage of 13,5 + 0,2 V and an ambient temperature of 25 + 10 ° C for the current fuel consumption does not exceed + (2 x 10-3 x Ax + 0,1), and for the rest (except temporary) - no more than +(0,5 x 10-3 x Ax + 0,1), where Ax is the value of the induced parameter.

The trip computer includes sensors for fuel consumption and vehicle speed. The first of them is installed in the fuel line between the pump and the carburetor. This sensor has a conversion factor of 16 pulses per 000 liter of flowing gasoline.

The second one is installed on the speedometer drive at the gearbox, while the possibility of installing a flexible shaft for driving a mechanical speedometer is preserved. The sensor generates 10 pulses per revolution of the speedometer shaft (one meter of distance traveled). The Niva car has wheels of increased diameter, and therefore the MK-21093 computer without modification will give an unacceptably large error.

In general, the computer can be installed on any European car that has a carburetor engine with a total cylinder capacity of up to 2,8 liters and a speedometer drive that complies with class A2 DIN 75532 (external thread of the M18x1,5 fitting and one turn of the flexible shaft corresponds to one meter of vehicle mileage) .

Structurally, a computer consists of three main blocks (Fig. 1): a processor, a digital indicator and a keyboard, each of which is assembled on a separate printed circuit board. All boards are placed in a plastic casing, on the front panel of which there are control buttons, LEDs and a digital indicator board. The supply voltage and signals from the sensors are supplied to the computer through the connector's pin block.

The output signals of the fuel consumption and vehicle speed sensors are fed to the DD1 microcomputer through pulse shapers, each consisting of an input filter (Z1 and Z2) and a comparator (U1 and U2). All processor nodes are powered by a stabilized power supply connected to the car's on-board network.

The code converter DD2 and the indicator HG1 of the display unit are powered by the voltage converter of the processor power supply. The voltage to the converter comes from the ignition switch. The voltage regulator and the converter make up the power supply unit G1 of the trip computer.

The operation mode of the device is controlled and the displayed parameter is selected by closing contacts S1-S10 of the keyboard. The keyboard also includes a DD3 decoder and a set of HL1 LEDs that indicate the selected parameter and illuminate the inscriptions on the instrument panel at night.

After connecting the trip computer to the on-board network, it is necessary to perform the initial presets, as a result of which it switches to the information storage mode. Turning on the ignition puts the device into operating mode, the digital display and LED indicators on the front panel turn on. The voltage converter provides power to the anode (15 V) and filament (~ 2,4 V) circuits of the indicator.

When the car is moving, the microcomputer processes the information contained in the signals from the speed and fuel consumption sensors in accordance with the program recorded in it at the factory. The processing result is sent to the indicator.

To obtain the desired information, the driver presses the corresponding button on the keyboard, while the selected mode indicates on the keyboard that the LED has turned on and at the same time the digital indicator displays the parameter value. When driving at night, the side lights of the car are turned on and the voltage from the on-board network is supplied to the node A1, which is part of the processor, for adjusting the brightness of the indicator display. As a result, the brightness of the indicator board is reduced by 15...20 times, which provides more comfortable reading of information in low ambient light.

Schematic diagram of the trip computer processor is shown in fig. 2. All external devices are connected to the processor through connector X1. The processor is connected to the remaining blocks by thirty-six conductors, of which the first seventeen are connected to the display unit board, and the remaining nineteen to the keyboard board.

(click to enlarge)

The supply voltage from pin 5 of connector X1 through the VD2 diode, which protects the device from emergency polarity reversal, and the current-limiting resistor R3, is supplied to the DA1 microcircuit voltage regulator. The VD3 semiconductor limiter protects the input of the stabilizer from accidental voltage surges. Limit threshold - 35 V; in normal mode, the limiter is closed. To suppress the variable component of the on-board network voltage, capacitors C5 and C6 are provided.

After the ignition is turned on and voltage appears on pin 3 of connector X1, transistors VT1, VT2 open and the supply voltage (about 12 V) is supplied to the fuel consumption sensor (on pin 4) and a stabilized voltage converter made on transistors VT4, VT3, transformer T1 and working with a frequency of 50...60 kHz. From terminals 1 and 3 of the transformer T1, an increased alternating voltage is removed, which, after rectification by the VD6 diode (~ 15 V), is supplied to the keyboard unit. Variable incandescent (pulse) voltage for powering a luminescent digital indicator comes from a separate winding (pins 6-8) of the transformer.

The pulse output signal of the fuel flow sensor from pin 1 of connector X1 through the low-pass filter R5C2 is fed to the input of element DD1.1, which has a rectangular transfer characteristic (Schmitt trigger). Resistor R1 is the load resistor of the sensor. The pulse output signal of the speed sensor from pin 9 of connector X1 through the decoupling diode VD1 is fed to the load resistor R4 and through the low-pass filter R6C4 to the input of the same Schmitt trigger DD1.2.

On the element DD1.3, the "on - off" signal generator is assembled. While the ignition is not turned on and the transistor VT1 is closed, the input of the element DD1.3 is low, the output is high. This high level - the "off" signal - keeps the microcomputer in the information storage mode. A low level from the output of the element DD1.4 prohibits the operation of the generator on the elements DD2.3, DD2.4. When the ignition is turned on, a signal is generated at the output of the DD1.3 element to turn on the microcomputer in the form of a negative voltage drop.

The microcomputer is made on a DD3 chip. Its operation is synchronized by a built-in oscillator with a ZQ1 quartz resonator. The inputs of the microcomputer receive signals from the shapers and control buttons of the keyboard assembly.

The control unit for the brightness of the display is made according to the scheme of an autogenerator of pulses on Schmitt triggers DD2.3, DD2.4. Its operating frequency is 0,8 ... 1,2 kHz with a pulse duty cycle of 15 ... 20. The supply voltage of the external lighting of the car from pin 6 of connector X1 is supplied to the oscillator through the R19R18C15 filter and starts it. The output pulses of the generator (from the output of element DD2.4) from pin 5 of the output comb of processor contacts are fed to the display unit, and from pin 32 to the keyboard input.

At the same time, the pulses of this generator (from the output of the element DD2.3), together with the signals from the outputs D3 and G1 of the microcomputer, are connected to the inputs of the elements DD2.1, DD2.2 and to the base of the transistor VT5. The output pulses of these elements are also fed to the display unit (from contacts 3 and 4, respectively) to control the brightness of the glow of individual elements of the display. The pulse sequence with the frequency of the brightness control oscillator, taken from the collector of the transistor VT5 (pin 31 of the comb), is used in the keyboard unit.

The schematic diagram of the display unit is shown in fig. 3. Information about the numerical value of a particular motion parameter, generated by the microcomputer of the processor, from the input contacts 6-8, 10, 12-15 comes in binary code to the inputs of the code converters DD1-DD4. From the output of the converters, the signals in the "seven-element" code are connected to a four-digit vacuum luminescent digital indicator HG1 operating in a static mode.

(click to enlarge)

As soon as the input K of the code converters receives a pulsed voltage (from pin 5), the constant voltage on the anode elements becomes a sequence of pulses with a large duty cycle. As a result, the brightness of the glow of the included elements of the scoreboard decreases.

On fig. 4 shows a diagram of the keyboard block. It consists of non-latching SB1-SB10 buttons, DD1 decoder, two groups of LEDs - HL1-HL7 and HL8-HL15. The LEDs of the first group indicate the selected operating modes, and the second group illuminates the inscriptions on the instrument panel at night.

When you press one or another button of the keyboard, the operating mode of the microcomputer changes, and it transmits the corresponding information to the display unit and simultaneously to the decoder DD1 of the keyboard - one of the LEDs will turn on, signaling the selected mode.

Just as it happens in the display unit, here, with the inclusion of the side lights of the car, the pulse voltage from the generator DD2.3, DD2.4 in the processor is supplied (from pin 32) to the inverse strobe input SB of the decoder DD1 (pin 4) of the keyboard - brightness the glow of the LEDs HL1-HL7 decreases.

The brightness of the illuminating LEDs HL8-HL15 is controlled by a switching transistor VT5 located in the processor.

The trip computer uses fixed resistors C2-33, C2-42v (R3 in the processor), oxide capacitors - K50-35, tuning - KT4-21b (C18 in the processor), the rest - K10-73-1b. The buttons in the keyboard are PKn159-1 (they can be replaced by PKn159-3).

Bipolar transistors KT9180B and KT817G in the processor are replaceable by transistors of the BSIT KP965V and KP961V structure, respectively. Instead of LM2931AT-5, you can use the domestic stabilizer KR1158EN5A. Foreign LEDs are used in the keyboard in order to ensure maximum efficiency of the device.

Trip computer MK-21093 is protected by a model certificate and a patent for an industrial design.

Authors: I. Nechaev, G. Rudominsky, Kursk

See other articles Section Automobile. Electronic devices.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Life on Mars 10.09.2013 Scientists from the University of Nevada have found another circumstantial evidence that life on Earth could actually originate on Mars. Recently, Professor Steven Benner of the Westheimer Institute of Science and Technology has already stated that life came to Earth from Mars and the evidence for this is molybdenum and boron, which are much more abundant on Mars than on our planet. Now, scientists from Nevada have discovered that Martian phosphates are much more water-soluble than similar terrestrial minerals. This means that life on the Red Planet was easier to originate than on ancient Earth. Phosphates are a key element for life; without them, life would not have been possible. That is why the study of methods for extracting phosphates from minerals can help unravel the mystery of the origin of life on our planet. Until now, research in this field shows that phosphate-containing minerals do not dissolve very easily. This is the so-called "phosphate problem" of the origin of life: how could life on Earth have appeared in conditions when there was not enough phosphate in the environment. The answer to this question may be the Martian origin of all life on Earth. The fact is that there are much more phosphates on Mars than on Earth. It remains to be seen how soluble they are in water. Of course, American scientists did not have rock samples brought from Mars. However, they managed to synthesize the minerals chlorapatite and meryllite found on Mars by unmanned vehicles. Then the rock samples were exposed to water with different pH levels for different periods of time. The researchers then measured how much phosphate dissolved in the water and how long it took. It turned out that both "Martian" materials saturated water with phosphates faster than their terrestrial counterparts, in some cases 45% faster. These figures may seem insignificant to some, but they have a significant impact on the probability of the origin of life. Of course, a study conducted by American scientists does not prove that terrestrial life originated on Mars and only then moved to Earth. However, this study makes this version a little more plausible. In addition, it shows that the conditions for the origin of life were not only on Earth, but also on other planets. This means that there could be many habitable planets in our galaxy.

Other interesting news:

▪ Created an artificial nerve to combat chronic pain

▪ Atomic clocks will make space exploration easier

▪ Tellurium Mini Transistors

▪ 802.11ac Devolo WiFi Stick ac adapter

▪ OLED will be 15% brighter and more durable

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Audio and video surveillance. Selection of articles

▪ article Daily bread. Popular expression

▪ article Which cities in the world are among the top ten rainiest? Detailed answer

▪ article Electrician for the repair of electrical equipment at the water supply site. Standard instruction on labor protection

▪ article Electronic ignition system for car heater (ZAZ). Encyclopedia of radio electronics and electrical engineering

▪ article Funny fan. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024