Simple system of the radio notification

02/22/2017 - 10:03

Sometimes for the remote notification at garage or car protection enough elementary system. In this case can be useful offering my device consisting of a radio transmitter, 26945 kHz working at fixed frequency and the narrow-band receiver.

the Electric circuit of the transmitter is given by font on fig. 2.73. The high-frequency part consists of two cascades on transistors VT1, VT2 and has минималь aching number of adjusting elements.

Pиc. 2.73. The radio transmitter

It simplifies its manufacturing and ensures functioning of the circuit without transmitter fine tuning in a range of frequencies 26. . 30 MHz
at change of quartz setting working frequency. />

Coils of throttles of L1 and L2 are reeled up by PEL wire in diameter of 0,12 mm on the MLT-0,5 resistor case with nominal resistance 1... 1.8 kiloohms also contain 50 rounds (the design is shown on fig. 2.56). L3, L4 and L5 coils are carried out on a dielectric framework in diameter of 5 mm with a carving for in the core with carving М4. They contain soot-
vetstvenno 14, 14 and 15 rounds of a wire of PEL in diameter 0.4... 0,5 mm. The L4 coil settles down horizontally on an assembly payment. As the core it is possible to use brass screws (for this purpose it is required to cut a head and to execute a cut — shlitsa for a screw-driver). Before in them it is greased with any not drying viscous hermetic. />

In the circuit are applied by font MLT resistors. unpolar K10-17 condensers (with the minimum TKE), tuning С10 the K4-236 type, electrolytic С4 — K52-1 for 22 Century

the Modulating part of the transmitter is executed on one digital chip of KMOP of a series. On the elements D1.2 and D1.3 the generator of low-frequency impulses with frequency (about 1000 Hz) which switch by means of an electronic key on an element of a chip of D1.4 a food on the high-frequency oscillator is accurate. Modulating frequency it is possible to establish by means of change of the elements C2, R2 and R3 any in a range from 300 to 2000 Hz.

When the chain of the F1 sensor is closed by font — the generator does not work and all circuit in waiting mode consumes a microcurrent (no more than 0,05 мА). At F1 disconnection — the transmitter turns on. The working transmitter from pulse 100 % modulation consumes a current no more than 100 мА.

the Supply voltage of the circuit of the transmitter can be in a range 9... 13 V.Pri etom the target capacity of the transmitter in an impulse makes no more than 0,8 W.

Control of the circuit consists in receiving by means of the arranged cores of coils of the maximum amplitude of target VCh of a signal. For this purpose at first we connect active loading equivalent to the aerial, fig. 2.74, both the core of coils L3, L4 and the C10 condenser we achieve a resonance in P-filter contours.

Final fine tuning is carried out by font at the connected aerial on the indicator of an electromagnetic field by means of the ferrite core of the L5 coil and the C11 condenser. The simplest circuit of the broadband indicator of a field is shown on fig. 2.75. One of possible options of performance of the indicator of a field is given on fig. 2.62.

the Aerial of the transmitter can serve font as p the metal probe (800... 1200 mm) or any tense wire in length about 1... 2.5 m. At device installation on stationary object the aerial from a wire less draws of font attention and sometimes allows to make it on the sizes of a commensurable wave with a length (to 10 m) that increases efficiency of radiation of a signal.

At figurative option of a design of the transmitter as the aerial is convenient for using p telescopic, from any household radio receiver or the TV. And 8 accumulators of the NKGTs-0,5 type will be suitable for a food of the device.

Fig. 2.74. Connection to the equivalent aerial of loading for setup of the transmitter

the Fig. 2.75. The broadband indicator of a field

All elements of the circuit of a radio transmitter are located font on the printed-circuit board in the size of 105х35 mm from unilateral стеклотекстолита in the thickness 1... 2 mm, fig. 2.76.

the High-frequency part of the receiver is executed by font on an analog integrated chip of DA1 (К174ХА2) according to the supergeterodinny circuit, fig. 2.77. Internal heterodynes it is stabilized on frequency by ZQ1 quartz (26480 kHz) that provides reliability of reception at change of temperature and feeding tension. Frequency a heterodyne is chosen lower than frequency of an accepted signal on 465 kHz. Intermediate frequency allocated by the internal mixer amplifies and arrives on the detector VD2. The VD1 diode improves work of the built-in system of automatic adjustment of strengthening at reception pulse modulated
signals. That provides operability of the receiver and at a short distance from the transmitter. />

the Preliminary amplifier of a high-frequency signal on the VT1 transistor allows to increase sensitivity of the receiver to 3... 5 мкВ (internal noise of a chip limit further increase in sensitivity). The entrance contour of L1-C2-C3 and the collector VT1 transistor (C5-L3) are adjusted on frequency of the transmitter by means of ferrite cores. The probe from a rigid wire in length of 400 mm can be the aerial of the receiver.

Fig. 2.76. Topology of the printed-circuit board and arrangement of elements of a radio transmitter

Fig. 2.77. A high-frequency part of the receiver

Low-frequency impulses after the detector VD2 arrive on the amplifier transistorized by VT2... VT3, fig. 2.78. Face value of R13 and R18 resistors steals up so that at an entrance low-frequency signal amplitude 20 мВ
(for control a sinusoidal signal to submit from the generator) — day off had symmetric restriction of amplitude. to

In order that the receiver gave to font a notification signal only at reception of the (against other signals and hindrances), on the elements C26... С28, L7 is accurate the narrow-band filter on frequency about 1000 Hz. The strip of the filter makes 200 Hz. In case of emergence on an exit of the detector of the receiver of frequency in this range with level more than 20 мВ on an exit of the logic element DD1.2/8 will appear short impulses. They charge the C30 condenser to level the ravine. "1". In this case on an exit of the DD1.3/12 inverter there will be a ravine." About". The VD4 diode is locked that allows operation of the sound oscillator on DD1.4, DD1.5. Frequency of the generator can be arranged by means of the R23 resistor so that to receive the maximum loudness of work of a pyezoizluchatel of ZGI 8 (ZP-25). Usually this frequency about 2 kHz (an internal resonance of a radiator).

the Topology of the unilateral printed-circuit board of the receiver is given by font on fig. 2.79. The elements R22, R23 and С31 are located over DD1 chip. For receiving high density of installation the majority of resistors are established vertically on a payment.

At installation are used by font constant resistors of the C2-23 type, tuning R18 of the SPZ-19a type, type K10-17 and KM-4 condensers, polar С9, С12... С14, С20 the K50-35 type on 22 V. Pyezoizluchatel it is possible to replace ZGI 8 on ZP-25. KD521 diodes are replaced with any pulse.

L1 and L3 Coils are executed on a framework in diameter of 5 mm by wire PEV-2 in diameter of 0,23 mm (the design is shown on fig. 2.64) and contain on 14 rounds. The L2 coil has a design for horizontal installation on a payment, fig. 2.55. It contains in windings: 1 — 12 rounds, 2 — 3 rounds over primary winding, a wire in diameter of 0,4 mm. For control any is used the high-frequency ferrite core.

Design of coils of contours of intermediate frequency of L4... L6 is shown on fig. 2.17. They can be used already ready, from tiny radio receivers, or — in the presence of all entering knots — are carried out independently by PEL wire in diameter of 0,1 mm and contain on 80 rounds.

For manufacturing of the coil of the L7 filter are used by font two armored ferrite (600. . 2000НМ) cups of standard size Б14 (without the tuning core). The winding is reeled up by PEL wire in diameter of 0,08 mm before filling of a dielectric framework and settles down in ferrite cups. Resonant frequency of a contour of L7-C27 (1000 Hz) can differ from the specified. In this case it is required in the transmitter at control to establish the same frequency of modulation.

Setup of the receiver we begin with the decoder at a circuit food on pryazheniy 7,5 V.Podavaya a sinusoidal signal from LF of the generator (15... 20 мВ) on a decoder entrance, R13 and R18 resistors we achieve symmetric restriction of a signal on the R19 resistor at change of feeding tension.

Fig. 2.78. Receiver decoder

Fig. 2.79. а) Topology of the printed-circuit board of the receiver

Fig. 2.79. б) An arrangement of elements

After that we determine resonant frequency of the filter (we measure it).

Adjustment of a high-frequency part of the receiver is reduced by font generally to control of contours by means of ferrite cores. What will need the high-frequency generator.

the Receiver should keep working capacity at change напряже a niya in a range 6,6... 9 Century.

the current Consumed by the circuit makes no more than 12 мА. In case of use for a food of the receiver of six accumulators of the D-0.26D type continuous independent work can make 20 hours. to

the Design of the case of the receiver is similar to font shown for the electroshock device. Elements of a food take place in the glasses stuck together from a cardboard. The second printed-circuit board fastens on lateral walls from plexiglas in thickness 4... 5 mm (the same payment provides electric connection between accumulators). The framework formed of two payments turns around a cardboard and is glued (it should act in film easily). After that to give a pleasant look to the case the decorative film under color of a tree (more conveniently if it is being self-glued) will help.



Simple system of the radio notification

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