|
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 Radio search for pets. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Consumer electronics Figure 1 shows a diagram of a "radio collar" for searching for cats and small dogs at a distance of several hundred meters. Using the principles of the device of such structures, it is possible to create equipment for searching for larger animals and at greater distances. The search system generally contains a radio transmitter (radio beacon), which is placed on the pet's collar, and a radio direction finder. The principle of operation of such a device is clear: with the help of a direction finder receiver, they constantly determine the direction of the search and thus reach the desired target in the shortest possible way. There is a problem that needs to be solved in the first place: to provide your dog or beloved cat with a radio beacon. As a rule, such an "object" usually has a small size, so the radio beacon must also be small. There are many options for its design, but one of the most convenient is the collar. Moreover, in this case, the antenna can be a frame. It may not be very effective in this application, but it is simple.
The radio beacon consists of an RF generator with quartz frequency stabilization on a VT1 transistor and a low-frequency modulator generator on a DD1 chip. On the elements DD1.1 and DD1.2, a rectangular pulse generator with a repetition rate of several hertz is assembled, and on the element DD1.3 there is a buffer stage that periodically opens and closes the transistor. When the transistor is open, the RF generator starts to work. It contains an oscillatory circuit formed by elements L1, C5, C2, C4. Coil L1 simultaneously acts as an antenna. The radio beacon operates in the CB band, or rather, at a frequency permitted for radio control systems for models and mechanical toys (27,12 MHz). The device is powered by a battery of batteries or galvanic cells with a voltage of 3 V or more. There is no special power switch, and switching on is done by inserting the XP1 plug into the XS1 socket. Most of the details of the radio beacon are placed on a printed circuit board (Fig. 2) made of double-sided foil fiberglass. A DD1 chip is installed on one side, and a ZQ1 quartz resonator and a VT1 transistor are installed on the other.
In order to achieve small dimensions, elements for surface mounting are used - resistors R1-12, capacitors K10-17 and transistor KT3129B9. In the places shown by curved arrows, both sides of the board are connected to each other. Socket XS1 is soldered to the board using short wires. After checking the performance and configuration, the board is covered with epoxy glue. The GB1 battery is made as a separate module and is connected to the board with short wires (it is better to do this through a small-sized connector). The design of the radio beacon is shown in Fig. 3, and the appearance - in Fig. 4.
On the collar 1 itself (leather, fabric), a board 2 is fixed, and the battery, socket and plug are fixed in such a way that when the collar is put on and fixed with fastener 3, the plug is inserted into the socket and the beacon turns on. Coil L1 (pos. 4) is made in the form of a wire with a diameter of 0,2 ... 0,3 mm in insulation, mounted on a collar. When the collar is removed, the socket and plug are separated and the radio beacon stops working. The length of the coil wire L1 is determined by the length of the collar. Establish a radio beacon in the following sequence. The inputs of the DD1.1 element are temporarily connected to the negative terminal of the power source, and a 1 pF capacitor is installed in parallel with the quartz resonator ZQ4700, which puts the device into the generation mode at the frequency of the LC circuit. The collar is put on the object, and by selecting the capacitor C5 (it is located directly on the plug), generation is achieved at a frequency, possibly closer to the frequency of the quartz resonator. Control must be carried out using a frequency meter by connecting a conductor located next to the radio beacon to its input. After that, temporary connections and parts are removed. The radio beacon should give signals with a frequency of several hertz, this can be checked by a CB radio station operating in SSB mode. The direction finder receiver can be of various designs. One option is to use an SSB radio with a specially made antenna as a direction finder. It is better to make a special receiver-direction finder. The receiver (Fig. 5) is built according to the direct conversion scheme. It contains two antennas: WA1 loop and WA2 whip. UHF is assembled on transistor VT1, and a local oscillator with quartz frequency stabilization is assembled on VT2. Chip DA1 performs the functions of UHF with an adjustable transmission coefficient, a mixer and a preliminary ultrasonic frequency converter. DA2 is the final UZCH, which is designed to work on headphones with a resistance of 50 ... 100 Ohms.
Resistor R7 regulate the sensitivity of the receiver (adjustment range - more than 30 dB). The maximum sensitivity of the receiver from the input of the transistor VT1 is about 0,3 μV. Most of the receiver parts are placed on a printed circuit board (Fig. 6) made of double-sided foil fiberglass. The second side is left metallized (it is used as a screen) and is connected in several places along the edges of the board to the common wire of the first side.
On fig. 7 shows a photograph of the receiver.
Resistor R7 - SDR with a power switch, the rest - MLT, S2-33. Trimmer capacitor C2 - KT4-25, KT4-35, oxide - series K50, K52, K53, the rest - K10-17, KD. Quartz resonator ZQ1 - at the same frequency as in the radio beacon. Battery GB1 - "Krona", "Korund", "Nika", 7D-0,125. The design of the antenna system is similar to the recommended one, only the whip antenna is made removable. There is also a detailed description of its settings. Establishing the receiver begins with setting the mode of the transistor VT1 to DC. To do this, by selecting the resistor R2, a constant voltage on the collector is set within 3 ... 4 V. Then, by selecting the capacitor C11, and, if necessary, C14, the frequency of the crystal oscillator is set. It is best to do this by ear: by turning on the radio beacon, remote at a distance of several meters, they achieve such a state when the frequency of the radio beacon signal will be approximately 1 kHz. Then tune the antenna system. If at the same time the tuning capacitor C2 is in the position of maximum capacity, then in parallel with it it is necessary to install a capacitor of constant capacitance 20 pF and repeat the setting. Tests of the layout of the device were carried out by the author in an abandoned orchard. The detection range of the radio beacon signal (it was located at ground level) was 300 ... 400 m. With a weak signal (at the noise level), direction finding is more convenient to carry out at the maximum audibility, and with a strong signal - at a minimum.
Machine for thinning flowers in gardens
02.05.2024 Advanced Infrared Microscope
02.05.2024 Air trap for insects
01.05.2024
▪ Gaming TV Redmi Gaming TV X Pro ▪ Motherboards based on the H81 chipset from Gigabyte ▪ Cable Power Specification for HDMI Cables ▪ Low Dropout Voltage Regulators (0,4V)
▪ website section Television. Article selection ▪ article Sweet woman. Popular expression ▪ article What color are carrots? Detailed answer ▪ article Node UIAA. Travel Tips ▪ article JG1EAD All-Band Transceiver. 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