|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Watchdog with phone call. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Security devices and object signaling The guard devices described in amateur radio literature are usually suitable for guarding cars, apartments, garages and other objects. The device proposed here is also universal, and the function of automatic call of the subscriber is not associated with a significant circuit improvement. The logic of the watchdog is as follows. When the power is turned on, it forms a delay cycle, during which it does not respond to the state of security sensors. If the contacts of the sensors are closed, then after the generated delay cycle, the device is set to the watchdog mode. If, in watchdog mode, the sensor contacts open with a delay, the device generates a pause before turning on the alarm actuator; during this time, the device can be turned off. However, if the sensor contacts open without delay, the actuator immediately sounds an alarm. When the contacts of any of the security sensors are opened, the device operating in the guard mode automatically calls the subscriber at the telephone number specified by the user. During each of the five call attempts, into which the full cycle of the machine is divided, the line is reset, followed by dialing and a waiting pause. The acoustic alarm signal emitted by the executive device is easily identified by the subscriber when lifting the handset. The execution time of one cycle attempt is about 40 s. The machine can work both independently and as part of another alarm system. In addition to the above functions, the device provides for turning off all telephone sets for silent dialing of the subscriber's number. The circuit diagram of the watchdog is shown in fig. 1. It includes a handset with a dialer on the K1008VZh1 chip, supplemented by an A2 circuit board circled in fig. 1 with dash-dotted lines.
A full cycle of work sets a counter-divider by 60 (output M of the DD1 microcircuit), to the synchronous input of which pulses are fed from the output F (fg / 2e6). And since the pulses for switching the handset are taken from the outputs T1 and TK (giving a phase shift of half a period and a frequency fg / 2e6), then when sixty pulses pass from the output F, six pulses pass from any of the outputs T1-T4. The first pulse from the T4 output is used to generate the alarm triggering delay implemented by the cascade on the DD3.2 trigger. Elements C6, R10, R15, VD4 included in this cascade are optional - they are only needed to cut off the first ("smooth") edge of the pulse when power is supplied to the DD1 chip from the encoder. If, however, the encoder is not used, then pin 2 of the T4 output of the DD1 chip can be connected directly to pin 11 of the C-input of the trigger D03.2. In this case, the tripper is set to the zero state by a positive drop at the output T4 after it has been set to the single state by the input S of the sensors S 1, i.e., after passing the first of five call attempts. The low-level voltage at the output of the trigger DD3.2 does not prevent the opening of the transistor VT3 by the volume flowing through the resistor R16. Thus, after the delay, there are five attempts to call the subscriber. The same high-level pulse from the output T4 opens the key DD2.2 and thus connects an additional capacitor C5 in parallel with the generator capacitor C7; the clock frequency of the generator in this case decreases and remains unchanged until the decay of the pulse from the T4 output passes. The time-setting circuit R4R5 and parallel-connected C7 and C5 determine the duration of one cycle, and the R4R5C5 circuit determines the duration of the switching pulses coming from the outputs T1 and T3, as well as the pauses between these pulses. The delays necessary for switching the line and dialing the numbers are provided by a phase shift between the pulses at the outputs T1 and T1 when the generator is operating at a high frequency and are approximately 1 s. When the sensor S1 is triggered, a high-level signal is fed to the R-inputs of the counters of the DD6 microcircuit; as a result, a low-level voltage is set at the output F, blocking the passage of pulses to the R-inputs through the R2VD1 chain. The low-level signal is held at the output F for a full cycle, and it also opens the transistor VT2.3 with the key D11. The infrared LED VD13 is turned on by this signal, and the voltage drop across the photodiode VD11, illuminated by the VD4.1 LED, decreases, which leads to the opening of the DD21 key. The key, when activated, connects conclusions 5 and 1008 of the K1VZhXNUMX microcircuit, i.e., like the corresponding parallel key of the telephone handset keyboard with the "" " symbol, disconnects the line. The channel associated with the T3 output of the DD 1 microcircuit works similarly, with the only difference being that here the high-level signal opens the VT2 transistor, and the DD4.2 key connects pins 19 and 5 of the K1008VZh1 microcircuit, causing, like the key with the symbol "*" , executing the redial. Thus, it turns out that a low-level pulse from output F connects the handset to the line, a high-level pulse lasting about 1 s causes the line to be reset, and the high-level pulse following it after a pause from output T3 causes the last memorized number to be dialed again. At the end of the full cycle, the high-level voltage at the output F of the counter of the DD1 chip opens the DD2.1 key and stops the generator. On the DD3.1 trigger, a delay has been implemented for setting the device to armed mode. When the power is turned on, this trigger is set to its initial state by the asynchronous input S and the DD1 chip is reset. Transistor VT3 turns out to be a closed high-level signal from the direct output of the trigger DD3.1 and remains closed until a positive voltage drop arrives from the output F of the counter of the DD1 microcircuit to its input C, i.e. until the end of the full cycle. Through the diodes VD5 and VD6, the signals from the trigger outputs of the DD3 microcircuit are fed to the logic inputs of the DD2.3 and DD2.4 switches, prohibiting line switching and dialing during the current empty cycle cycle (call attempt), which determines the delay time for arming the device. The composite transistor VT4VT5, operating in key mode, switches its collector load (output 9), and relay K1, when activated, switches off parallel telephones with contacts K1.1. The load of the composite transistor can be a siren, described in [2], or another signaling device. When the power is off, the device does not affect the operation of the handset, since the key DD4.1 is open at this time and the state of the handset is determined by its mechanical switch SA3, modified to switch the outputs of the "Reset" button of the keypad, and the key DD4.2 is closed and does not affect the operation of the keyboard. The sensor is connected without delay to the wire break between terminals 1 and 2 of board A (in Fig. 2 - instead of the corresponding wire jumper). For arming and disarming, you can also use the code device published in [3]. Its setup and reset outputs are connected to the corresponding input of the trigger DD1, and the power to the DD1 chip falls from the inverse output of the trigger 02.2 of the code system described there. The security device proposed here is also suitable for working together with a conventional push-button telephone set. In this case, it is only necessary to replace the IR LEDs in the transistor switches with an electromagnetic relay with the appropriate parameters and use its contacts for switching electronic switches. In this case, of course, an additional three-wire flexible cable will be connected to the telephone set. Now briefly about the details. Oxide capacitors - K50-16 or K50-35, the rest of the capacitors are any ceramic ones, including those with a large TKE; resistors - MLT or S2-29. Diode VD17 - any of the KD208 series or similar. Diodes of the KD522 series can be with the letter index B or other silicon impulses. VD9 LED - any of the AL307 series; VD11 and VD12 - AL107 or AL106 series. The functions of photodiodes VD13 and VD14, operating in valve mode, can be performed by AL106A light diodes, selected according to the minimum dark current. Transistors KT3102E and KT3107A are interchangeable with any low-power of the same structures with a base current transfer coefficient of at least 80. The power supply at a current of at least 100 mA must provide a voltage of 12 ... 13 V - this, of course, does not take into account the current value consumed by the load of the VT4VT5 composite transistor. Details of the security part of the device and the switch (block A2) are mounted on independent boards made of one-sided foil fiberglass. The printed circuit board of block A1 and the placement of parts on it are shown in fig. 2. Installation of the parts of the A2 block is simple and can be carried out by the hinged method. The board of block A2 is inserted into the body of the handset in a free place, for example, near the dynamic head, and is isolated for reliability from other parts of the apparatus. It is convenient to place photodetectors VD13 and VD14 in the lower part of the handset housing so that their lenses on the handset placed on the stand are directed downwards to the corresponding IR LEDs VD11 and VD12 placed in the stand. Holes for LEDs in the stand and for photodiodes in the tube are drilled immediately with the tube inserted into the stand to ensure good alignment. The distance between the LED and the photodiode of each opto-pair can be within 0,5...3 mm. The LEDs mounted in the stand are connected to the board of the A1 block with a three-wire flexible cable (they are not laid in well-visible places), and the board itself is placed in a metal or plastic case of suitable sizes. The VD9 LED can be displayed on the front panel of the housing. With error-free installation, the establishment of a security device is reduced to the selection of capacitor C5 until the desired duration of the response delay is obtained. The need for this is explained by the fact that the state of the outputs T1-T4 for different copies of the K176IE12 microcircuits after reset is ambiguous, but after each reset this state is restored. To improve the reliability of the keys of block A2, the KS133A zener diode operating in the handset should be replaced with KS147A, and between terminal 2 of the DD4.1 element and the conductor going to terminals 3,6 and 14 of the K1008VZH1 dialer chip, it is advisable to include a resistor R25 with a resistance of 240. .330 kOhm. Literature 1. Pukhalsky G. I., Novoseltsev T. Ya. Designing discrete devices on digital microcircuits. - M.: Radio and communication, 1990. Author: D. Alekseev, Moscow; Publication: N. Bolshakov, rf.atnn.ru
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Chinese children will be limited in the use of gadgets ▪ New professional A3 scanners ▪ DisplayPort support in USB Type-C ▪ Subcompact crossover Hyundai Exter
▪ section of the site Microphones, radio microphones. Article selection ▪ article Servant of the people. Popular expression ▪ Article When did the advertisement appear? Detailed answer ▪ article System Administrator. Job description ▪ article Sensor The engine is running. Encyclopedia of radio electronics and electrical engineering
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page