Infrared car guard. Encyclopedia of radio electronics and electrical engineering

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

 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.

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.

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.

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.

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:

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 3D printing of tiny details 29.12.2022 Engineers at the California Institute of Technology (Caltech) have developed a new method of 40D printing with pure metals or alloys, which allows for a resolution of 3 microns, which in some cases exceeds the capabilities of other similar technologies by an order of magnitude. The process, which is something of a symbiosis of chemistry and XNUMXD printing, will make it possible to manufacture parts for tiny MEMS (microelectronic mechanical systems) devices that are widely used in space, transportation, biomedical equipment and many other things. The traditional 3D printing process consists of laying down material layer by layer. This, in turn, allows the creation of forms that cannot be obtained by traditional machining methods. Industrial metal 3D printing processes use a laser to melt metal powder at a precise point, and the best of these methods can now achieve resolutions of 100 microns. The problem here is that some of the metals, copper and silver, for example, have such a high thermal conductivity that even with a well-focused laser beam, heat spreads and melts the metal powder around a given point, which reduces the resolution of the printing process. In the new printing process, instead of pure metals in powder form, the process is carried out in a volume filled with a special hydrogel. This material is a base of flexible polymer chains, the gaps between which are filled with water. Only in this case, this water still contains a high concentration of metal salts, from which the final printed object will consist. Further, everything happens as with the usual method of laser printing with plastic. The light of ultraviolet lasers focused at a given point causes polymerization, polymer molecules at this point bind to each other and become rigid. And so, sequentially processing the hydrogel layer by layer with a laser, the structure of the future object is formed. After that, the laser-processed material is subjected to heat treatment at temperatures from 700 to 1100 degrees, depending on the print material. The temperature is chosen so that it is slightly below the melting point of the metal or alloy used, while the hydrogel begins to burn out, and in the places of its polymerization, threads are formed from metal particles that fuse with each other. Moreover, the hydrogel burning process is implemented in such a way that the metal from the non-polymerized areas settles on the already formed metal chains, strengthening and compacting them in this way. Using this method, the Californian researchers printed various objects from pure copper, nickel, silver, and several types of alloys as a demonstration of the new technology's capabilities. And now a special department of the California Institute of Technology has already registered a company called 3D Architech, which will patent, further improve, commercialize and license new XNUMXD printing technology.

Other interesting news:

▪ On the issue of transgenic products

▪ Transmission of optical communication without wires over long distances

▪ ESP32-SOLO-1 WiFi module for low-end IoT devices

▪ PHILIPS introduced a mirror-TV

▪ Intel Core i7-3960X Extreme Edition and Intel Core i7-3930K six-core processors

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Experiments in chemistry. Article selection

▪ article Votes are weighed, not counted. Popular expression

▪ article Which chemical element was obtained as a side effect of trying to isolate gold from urine? Detailed answer

▪ article Adjuster of cold forging equipment and dies on presses. Standard instruction on labor protection

▪ article Simple stereo mixer. Encyclopedia of radio electronics and electrical engineering

▪ article Mysterious nine from coins. 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