Menu English Ukrainian russian Home

Free technical library for hobbyists and professionals Free technical library


ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Infrared car guard. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Automobile. Security devices and alarms

Comments on the article Comments on the article

This is a remote control system with frequency coding and long exposure to the photodetector. Of course, frequency coding is not the height of perfection, but nevertheless it works effectively. In order for the scanner frequency at a certain moment not to accidentally coincide with the autoguard frequency, a 2-second time delay is used, which almost completely eliminates random frequency selection.

The autoguard includes a remote control on infrared LEDs of the AL107B type, made according to a well-known scheme. Also included in the autoguard is a K176IE12 clock chip and a Q1 quartz resonator with a frequency of 32768 Hz to form time intervals.

The main technical characteristics of the device:

  • Time to switch to security mode, s.......20
  • Alarm duration, s.......40
  • Alarm interruption frequency, Hz.......1
  • Alarm delay time, s ......2
  • Current consumption in armed mode, no more than, mA.......10
  • PCB dimensions, mm ......60x65
  • Control panel dimensions, mm ......25x30

Schematic diagram of the remote control is shown in Fig.1.

Infrared car guard
Ris.1

The remote control includes a multivibrator on the elements DD1.1-DD1.3, an inverter DD1.4, a pulse key on transistors VT1, VT2 and infrared light-emitting diodes VD1, VD2. The multivibrator frequency is adjusted by selecting the resistance of the resistor R1. The printed circuit board of the control panel is shown in Fig.2.

Infrared car guard
Ris.2

To power the remote control, you can use the Krona battery, which will ensure its long-term use.

The schematic diagram of the autoguard is shown in fig. 3. Autowatch contains a counter-shaper of time intervals on the DD2 chip, two triggers on the elements DD1.3, DD1.4 and DD3.2, DD3.3, a receiving device on the DD4 chip with a VD6 photodiode and a key on transistors VT2, VT3.

Infrared car guard
Fig.3 (click to enlarge)

When the device is turned on with the SA1 toggle switch (before leaving the car), the capacitor C1 sets the counters of the DD2 microcircuit to the initial zero state with its charging current. At pin 10 of the DD2 chip at this time, the log. "0", which is input to the element DD3.4 and opens it. From pin 6 of the DD2 chip, pulses with a frequency of 2 Hz passing the DD3.4 element and arrive at the clock input C (pin 7) of the DD2.1 counter are the same time, the zero level at pin 10 of the DD2 chip, inverted by the DD3.1 element, blocks the trigger assembled on the elements DD3.2 and DD3.3, and prohibits the passage of the signal from the contact sensors SB1 -SBn, connected to the cathode of the diode VD3, through the transistor VT1 to the elements DD1.1, DD1.2. The guard is in this state until the counter DD2 counts 39 pulses with a frequency of 2 Hz. This time, equal to 20 s, gives the owner of the car the opportunity to exit the passenger compartment and close all doors. But after this time, a unit appears at the output 10 of the counter DD2, which closes the element DD3.4 and prohibits the receipt of counting pulses with a frequency of 2 Hz at the counting input C DD2. The same signal (log. "1"), acting on the inputs of the element DD3.1, unlocks the trigger on the elements DD3.3, DD3.2, and the circuit enters the car protection mode.

Car door switches can be used as contact sensors. The same push-button switches can be put on the hood l on the trunk lid. The cascade on the transistor VT1 serves as an inverter and at the same time protects the DD3 chip from failure when a positive voltage is applied to pin 1 while the power of the autoguard is turned off. When one of the contact sensors SB1 - SBn is triggered, the cathode of the diode VD3 closes to ground, the transistor VT1 closes and a positive potential is set on its collector, which switches the trigger on the elements DD3.3, DD3.2. At the same time, a log level is set at its output 4. "1". From the output of the inverter DD1.1 log. "0" goes to pin 1 of the element DD1.2 and opens it. From pin 4 of counter DD2, second pulses through element DD1.2 are fed to pin 7 of counter DD2 and the key on transistors VT2 and VT3, which turns on the horn relay Kf. Counter DD2 counts 39 pulses received at pin 7, and after 40 s is set to zero (at pin 10 - log. "0"). Then, according to the scenario described above, there is a 20 second delay (as when turning on the power), and the circuit goes into armed mode again.

To turn off the autoguard, a control panel is used that emits pulses in the IR range. The photodetector, consisting of a VD6 photodiode and a resonant amplifier on the elements DD4.1 DD4.3, receives a signal from the remote control panel. The frequency to which the device responds is set by the circuit elements L1, C9. Its resonant frequency should correspond to the frequency of the remote control multivibrator. From the resonant amplifier, the signal is fed to the constant voltage driver. If the frequencies of the circuit L1, C9 and the multivibrator of the control panel match, a log level appears at pin 10 of the DD4.5 element. "1". To prevent the auto-guard from triggering in case of an accidental coincidence of the frequencies of the device and the scanner, the circuit R19, C11 forms a time delay of 2 s.

After charging the capacitor C11, the signal is fed to pin 8 of the trigger on the elements DD1.3, DD1.4, which, at pin 11, generates a positive pulse that arrives at pins 5, 9 of the DD2 chip and resets the counter. The moment the device is turned off is indicated by the HL1 LED.

The printed circuit board of the autoguard is shown in Fig.4.

Infrared car guard
Ris.4

Coil L1 is wound on an SBR-23 core and contains, depending on the frequency, from 100 to 500 turns (from 16 kHz to 5 kHz, respectively) of PEV-1 wire 0,1 mm. To power the microcircuits in the circuit, a VD5 zener diode of the KS210 type with a stabilization voltage of 10V is used.

See other articles Section Automobile. Security devices and alarms.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Improving the efficiency of PbS quantum dot solar cells 14.06.2024

The latest solar technology research represents a significant breakthrough in improving the efficiency of PbS quantum dot solar cells. This method, based on the use of pulsed light, offers promise for simplifying the production and expanding the applications of these cells. A research team from the Daegu Gyeongbuk Institute of Science and Technology has developed an innovative method that uses pulsed light to improve the electrical conductivity of PbS solar cells. This method can significantly reduce the processing time required to achieve similar results. PbS quantum dot solar cells have significant potential in solar technology due to their photovoltaic properties. However, the formation of defects on their surface can reduce their performance. The new method helps suppress defect formation and improve electrical conductivity. Using strong light to complete the process ... >>

Magnetic Power Bank 5000mAh 14.06.2024

Huawei introduces a convenient and multifunctional charger to the market - Huawei SuperCharge All-in-One Magnetic Power Bank. This magnetic battery allows you to quickly and conveniently charge your Huawei phone anywhere, anytime. With a thickness of just 11,26 mm and a weight of 141 grams, this portable power bank fits easily into a pocket or bag, making it ideal for travel and everyday use. Despite its compact size, this battery provides enough power to charge your phone on the go. The new product supports wired charging with a power of 25 W and wireless charging up to 15 W (and up to 30 W when connected to an adapter), providing fast charging for both the power bank itself and other devices. The battery is compatible with various fast charging protocols such as SCP, UFCS and PD, making it ideal for a wide range of devices. The power bank is also compatible with Huawei phones that support wireless charging. ... >>

Changes in a father's brain after the birth of a child 13.06.2024

A recent study conducted by scientists from the Hefei Institute of Physical Sciences of the Chinese Academy of Sciences found interesting changes in the brains of men after becoming fathers. These changes were associated with involvement in child care, sleep problems, and mental health symptoms. Scientists found that men who became fathers experienced a loss of brain volume after giving birth. This volume loss was associated with greater involvement in parenting, sleep problems, and mental health symptoms. Researchers have found significant changes in men's brains between the prenatal and postnatal periods. In particular, there was a loss of gray matter volume, especially in parts of the brain responsible for higher functions such as language, memory, problem solving and decision making. Men who paid more attention to their children and spent more time with them lost more gray matter in their brains. This also affected their mental health ... >>

Random news from the Archive

GPS signal will measure wind speed over water 02.08.2013

Winds over oceans and lakes can be tracked by reflecting GPS signals. This will help meteorologists more accurately predict the weather and, in particular, catastrophic events such as tornadoes. On a global scale, NASA experts hope to better understand our planet's climate with a new method of measuring wind speeds.

Accurate weather prediction and climate modeling requires accurate knowledge of wind strength at various altitudes, or at least near the surface. On land, this task is more or less performed by simple weather stations, but over the oceans, over the "kitchen" of the world climate, it is more difficult to make measurements. Usually, disposable probes dropped from aircraft are used for this. However, these probes are not cheap: $750 each, and in fact, during a typical mission, a "hurricane hunter" consumes about 20 of these probes.

It is clear that to obtain a pattern of winds over a large area, dropped probes are not enough. To solve this problem, NASA has developed monitoring technology that measures wind speed by bouncing GPS satellite signals off sea waves. The accuracy of such a measurement is 10 times lower than that of drop probes, which are only 0,5 m/s wrong. At the same time, analysis of the reflection of GPS signals from waves makes it possible to monitor vast areas in real time, which is very important for forecasting hurricanes.

Thanks to GPS, you can now follow the winds without dropping sensors. Wind data can be collected from aircraft and satellites. Specifically, in 2016, NASA plans to launch a system of small satellites called CYGNSS that will measure GPS returns from low orbit. This will allow forecasting the movement of storm fronts. In the future, in addition to GPS signals, it will be possible to use TV broadcast signals from powerful satellite transmitters such as DirecTV and Sirius XM for monitoring.

Thus, extremely powerful satellites provide scientists with "free" monitoring of the oceans, which until now has been an extremely difficult task. All you need is a GPS receiver, some chips and some software. All this costs several hundred dollars.

Other interesting news:

▪ Sony Triporous Fiber sock material

▪ Communication with sleepers

▪ mosquito tomato

▪ Energy storage in red-hot graphite bricks

▪ 6-inch 720p smartphone Lava Magnum X604

News feed of science and technology, new electronics

 

Interesting materials of the Free Technical Library:

▪ section of the site Reference materials. Article selection

▪ article Burn the ships. Popular expression

▪ Article How much can you eat at one time? Detailed answer

▪ article Formium durable. Legends, cultivation, methods of application

▪ article Small hydropower. Encyclopedia of radio electronics and electrical engineering

▪ article Yakut proverbs and sayings. Large selection

Leave your comment on this article:

Name:


Email (optional):


A comment:





All languages ​​of this page

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

www.diagram.com.ua

www.diagram.com.ua
2000-2024