People who have been bitten by angry dogs suffer from obsessive phobia throughout their lives. The fear of homeless animals not only prevents you from moving around the city calmly, but also makes you worry about the safety of your own children. Sometimes getting to school or shopping requires scaring off a pack of stray dogs. A stick or stone against a whole pack is a disastrous idea, especially if a child has to defend himself.
How to scare dogs away
Using special dog repellers (daisers) is a real chance to protect yourself and your loved ones. These devices easily fit into a jacket pocket, backpack or handbag, and are just as quickly removed from there if necessary. It is important to understand the operating principles of different diffusers in order to choose the most powerful one. Among those currently on sale, the ultrasonic repeller is considered the most effective. . Its action is enough for 13 m, which means that the dogs will not have time to get close.
The cost of factory-made diffusers is quite high, so people often use homemade devices. Real craftsmen will be able to make any repeller with their own hands: chemical, ultrasonic or electric. Why buy an expensive device if the one you make yourself is no less effective?
Dog repeller
Do-it-yourself chemical dog repeller: what and how to make it from
Chemical dispensers are devices filled with a composition that is toxic to animals and humans. The principle of operation of the repeller is to spray a caustic liquid onto the mucous membranes of the dog’s eyes, nose, and mouth. It is difficult to assess the effectiveness of such a diffuser. Firstly, its use involves close contact with angry animals, which in itself is very dangerous. Secondly, when attacked large quantity There is simply not enough time to spray a can of “chemicals” on everyone.
For your information! Making a chemical repeller is easy. The work will require ingredients that can be found in any kitchen: ground black pepper, vinegar, mustard powder. Some people use shag instead of vinegar when making such a diffuser. The result is cans with different compositions.
How to make a chemical disperser at home?
Option #1:
- Preparing the container for chemical composition. As a rule, this is a 0.5 liter plastic bottle without a cap onto which a sprayer is placed.
- Mixing the composition: add pepper to the vinegar, shake everything together.
- The liquid is poured into the bottle and closed tightly. Not very convenient, but you need to carry it with you.
Option #2:
- Preparing a container for a chemical mixture. It is convenient if it is a 0.25 liter jar with a tightly screwed lid.
- Preparation of the caustic mixture: finely chop the shag, add pepper and mustard powder. Mix.
- Transfer everything into a jar and close the lid. Carry with you, when an aggressive dog attacks, pour the contents onto the animal.
Do-it-yourself ultrasonic dog repeller: diagram, powerful diffuser
The ultrasonic dissipator, which produces a sound that is unpleasant to the dog's ear, is highly effective. The advantages of this device are that it is absolutely harmless to people and works even over long distances. Stray dogs immediately pay attention to the ultrasound signal, quickly leaving the meeting place with a person. By using the device in a critical situation, you will be able to immediately disperse the entire pack, rather than fighting off each dog separately.
Dog repeller circuit
You can make an ultrasonic dog repeller with your own hands using different schemes powerful dizers taken from the Internet. They can be remade if technical skills allow, or used in finished form. The universal circuit of an ultrasonic dog repeller requires the presence of a microcircuit, transistors, resistors, and diodes. At the stage of assembling the ultrasonic repellent device, it is important to follow the recommendations of specialists:
- use a piezoceramic emitter during the manufacture of the diffuser, which will evenly distribute the load;
- To turn on the light, select LEDs D3. Their installation is carried out in the farthest part of the device;
- In order for the repeller to work at a frequency of 25 kHz, you need to take a resistor P35, but you should not experiment with frequency parameters. In this regard, it is better to stick to the settings of factory models;
- The power of the ultrasonic diffuser should not exceed 130 dB. Otherwise, the device will not only scare away the animal, but also cause significant harm to it;
- for long-term operation of the ultrasonic device, it should be equipped with slots for 8 9V batteries;
- checking ultrasound pulses is the final touch in the work. This can be done using an oscilloscope or a sound card compatible with a computer;
- if the device was prepared for stationary use (for example, for a summer residence), then it must be enclosed in a moisture-resistant case and equipped with clamps.
Electric dog repeller: components and assembly rules
An example of a homemade dog repeller
Due to ignorance of the principles of operation of an electric disperser, it is often confused with a conventional stun gun. Many people immediately refuse to purchase such a repeller, since it contradicts their ideas about humane treatment of animals.
Important! The electrodisser is not intended for close contact with the dog's body. The device only creates a loud intermittent noise effect that scares away aggressive animals.
To make an electric dog repeller at home, you will need the following elements: a plastic bottle, a high-voltage module, a micro button and a AA battery. Creation technology homemade device simple:
- Secure the AA battery and module using electrical tape.
- Solder the button and wires to the surface of the battery.
- After making the base for the repeller, you should cut the electrical wires.
- cut from plastic bottle neck, receiving a diffuser to enhance the sound signal and protect against voltage.
- Place the diffuser on the electrical module, making small cuts on the neck.
- It is good to glue the junction of the neck and the module.
Visual information about making an electric dog repeller can be obtained from YouTube videos made by people with special technical skills. There, the electrodisser is shown in action: the sudden crackle of electrical discharges has a depressing effect on dogs, and they hide. No matter how many stray animals you encounter, the loud blasts of an electric repeller will send everyone running.
Pay attention! Despite the tolerant attitude of most people towards homeless animals, it is unacceptable to be careless about one’s own safety. A dog is truly a man's friend, but only if it is taken care of from puppyhood and kept in decent conditions.
Stray dogs live by different laws, and it is difficult to predict their behavior in a given situation. Due to the trials that street animals have to endure every day, they become embittered and increasingly attack passers-by.
A homemade dog repeller will always protect a person, the main thing is to keep the device with you. No one knows where a dangerous clash with a pack will happen: during an evening walk, in an unfamiliar area, on the way to the house. Stray dogs may share prey, territory, or chase a bitch; you should not deliberately attract attention to yourself and try to calm the animals down. Task No. 1 in this situation is to leave the dangerous territory as soon as possible, but if that doesn’t work, use a repeller.
The problem of stray dogs is very acute in almost all cities of Russia; they are especially dangerous for cyclists, not only because they can bite, but because when they suddenly jump out of the bushes, you can lose control of the road. Dog chasers can help here; their operating principle is based on the emission of ultrasonic waves, inaudible to humans, but perfectly perceived by the dog.
The scheme has a range of about 13 meters and causes severe panic in wild dogs, keep in mind that this does not frighten fighting breeds, but can only make them angry. This design has been repeatedly applied and tested on ordinary stray dogs.
The master oscillator is made on a domestic digital microcircuit and five transistors (VT1-VT5), the generated rectangular pulses with a frequency of 1.5 Hz are supplied to a transistor stage, which amplifies them. The amplifier's emitter load is the BF1 piezoceramic head. The power circuit of the microassembly is well protected from accidental reversal of the polarity of a Krona battery by a VD3 diode, and filter capacitances C4 and C7 ensure the transmission of high-frequency and low-frequency oscillations, respectively.
The ultrasonic rectangular oscillations generated at pins 10 and 11 of the DD1 microcircuit have a low output power. Therefore, they need to be strengthened, for which we use a push-pull bridge amplifier on VT2-VT5. The emitter load of the amplifier is the BF1 piezoceramic head.
The power supply circuit of the microcircuit is protected from accidental polarity changes by the GB1 battery by the VD3 diode, and filter capacitances C4 and C7 ensure the passage of high- and low-frequency oscillations. The K561LA7 logical microcircuit can be replaced with a K176LA7, K1561LA7 or 564LA7.
If instead of the SP-1 piezo element you use the ACT-10 car piezo siren, the range of the dog repeller will increase significantly.
A piezo emitter can also be found in cheap speakers or from a music box, etc. When you press the SB1 button, the device turns on the power. You can see the drawing of the printed circuit board below, but taking into account the prostate, it can also be mounted using wall-mounted installation.
Let's consider another simple circuit of an ultrasonic generator from dogs that can keep an animal at a distance, shown in the figure below. The circuit is built on two square-wave generators on DD1, an amplifier and an emitter.
Dog repeller circuit
During the summer season, or as often happens, the question arises of how to deal with dogs that trample while you are not in your summer cottage.
Here is the answer to your question scare dogs away using ultrasound
Dog repeller circuit easy to assemble, and also suitable for a beginner radio amateur
Device diagram:
The device, as is already clear, is designed for frightening using ultrasound.
Device described has a range of up to 13 meters and a qualitative effect on dogs that are about to bite you. As already mentioned, of the many diagrams of ultrasonic dog scarers published on the Internet, the most common was the following diagram above.
On top of the board- piezo emitter SQ-340L. We can recommend using the ultrasonic sounder MFC-200 instead, which has a high acoustic pressure of up to 85 dB, which means a longer range.
The piezo emitter can be obtained from speakers, also from speakers that people call pancakes, from a music box, from calculators, and so on.
Assembly box The ultrasonic repeller was made from a housing from a failed VHF radio station made in China; you can use any other housing that you have at hand, a walkie-talkie, etc., the dimensions of which were used to guide the development, manufacture and assembly of the device.
On the right is the SB1 button, when pressed, the power is turned on. The battery is of the Krona or Corundum type, the main thing is to have an operating voltage of 9 volts.
You can also use lithium-ion batteries to power the device. A big plus will be the ability to charge.
Master oscillator assembled on a domestic microcircuit, it sets the frequency we need, and the transistor cascade amplifies it. Transistors VT3, VT5 - It is advisable to use high-frequency ones; the device works great if you use transistors like KT816. VT2 and VT4 - type KT315, KT368 or imported analogues like S9018, S9014. According to the circuit, it is better to use Schottky diodes; all polar capacitors must be supplied with a voltage of 15 volts. PCB devices is also attached to the article. This ultrasonic deterrent has been used on dogs several times and each time it performed even better than expected.
The dogs ran away and looking at the dog it was clear that the scarer was making a very unpleasant sound for them.
Attention! You should not turn the device on people at close range (close to the ears and eyes), our ears catch ultrasonic waves, but the brain is not able to decipher them and for this reason we do not hear the world where communication is at an ultrasonic frequency. When the power is reduced to 3 volts, a quiet whistle is possible, which can be heard, and at 9 volts the frequency increases and we stop hearing the whistle, since the piezo emitter begins to emit ultrasound. In general, this device is an active weapon of self-defense against dogs and more!
It's no secret that there are more and more homeless, stray, and aggressive dogs in our yards every day. Thus, you and I daily risk becoming a victim of the so-called “friends of man.” Consequently, you can only rely on your own strengths and the achievements of science. Below is a diagram of an ultrasonic dog repeller.
Basic electrical diagram.
The action of an ultrasonic repeller is based on the combined effect of ultrasound and flashes of light on animals. Ultrasound is inaudible to humans, but it has a depressing effect on dogs, causing them to feel fear, and they try to get out of your way. To increase power and optimal matching with the emitter, this circuit uses a symmetrical cascade with an output transformer at the output. An ultrasound generator with a frequency of 25 kHz is assembled on the IS1 K1211EU1 chip. The frequency of the generator can be adjusted using trimming resistor R3. At the output of the K1211EU1 microcircuit, two antiphase signals with a frequency of 25 kHz are obtained, which are supplied to the output stage on transistors T1, T2 and Tr1. 
The signal shape at the output of the K1211EU1 microcircuit.
The load of the transformer is a piezoceramic emitter KPUS-25T-16T or similar with a resonant frequency of 22-25 kHz. For optimal matching, the emitter is connected via inductor L1. LED D2, connected through a zener diode with a voltage of 5.6 V and a series resistor, serves as an indicator of battery discharge. When the LED lights dimly or goes out completely, you need to change the battery. LED D3 indicates that the device is turned on. Setting up the device consists of setting the frequency to 25 kHz using resistor R3 and checking the pulses on the emitter using an oscilloscope. When the emitter reaches resonance, the pulse takes on the shape of a sinusoid and has a maximum amplitude. 
Signal shape at the emitter.
The pulse transformer is wound on a small-sized ferrite core of suitable dimensions. Primary winding 2 x 20 turns PEL0.15 secondary winding 80 turns PEL0.15. 
Development board.
To further increase the power (for example, with a stationary version), you can increase the number of emitters to 5-10 pieces. In this case, transistors T1 T2 need to be replaced with more powerful ones, for example IRF 640.
A properly configured ultrasonic rodent repeller deflects the flame of a candle or lighter at a short distance. When approaching, the flame of a candle or lighter goes out.
Stray dogs can cause a lot of trouble: seriously frighten a child, bite a passerby and tear his clothes, cause severe injuries if the pack is large and aggressive. Dogs especially do not like cyclists, barking with hatred at people riding this type of transport. Sometimes it’s not easy for both postmen and ordinary passers-by walking through a wasteland favored by animals.
Therefore, it’s a good idea to have protection with you that can scare away four-legged aggressors. By the way, you can build this protection with your own hands. Read on to learn how you can make a chemical or electronic dog repeller with your own hands, look at the diagrams, and create masterpieces!
What you will need
For chemical repeller:
- vinegar;
- ground black pepper.
The second option for a chemical repeller:
- ground black pepper;
- shag;
- mustard powder.
This video will show you how to make a low-power dog repeller with your own hands:
Manufacturing technologies
- The easiest way to make an imitation is to take a plastic bottle with a capacity of up to 0.5 liters, fill it with vinegar and add a teaspoon of pepper. Then shake and put on the spray bottle. However, it is not very convenient to carry this with you.
- In another option, they buy the most “vigorous” cheap shag, finely grind it together with black pepper in a coffee grinder and get a very pungent cayenne mixture. To enhance the effect, add mustard powder. Place everything in a small plastic container that is easy to open. in case of threat, apply to the dog (nose, eyes, mouth). You can also stuff a firecracker with this and shoot from afar.
Below we will tell you how to make, although not the most powerful, homemade ultrasonic dog repeller with your own hands, with a useful diagram.
How to make an ultrasonic DIY dog repeller
Such devices are also called dogchasers - taken from English language. The operation of the device is based on ultrasonic radiation, which people do not feel, but dogs react to it by backing away and running away.
What you will need
Option 1
Ultrasonic device diagram one:
- piezo emitter (can be pulled out of a speaker, speaker, music box, calculator);
- battery type “Krona” with a voltage of 9 volts or type “L1028” with 12 volts, you can take two batteries from a mobile phone (lithium-ion);
- microcircuit K5 61LA7 or K176LA7, K1561LA7, 564LA7;
- three silicon small-sized diodes;
- five capacitors;
- five resistors per 100 kilo-ohms;
- 33 kilo-ohm resistor;
- 2 kilo-ohm resistor;
- four transistors from the KT3102 or KT3107 series;
- one silicon transistor with a base current gain of at least 30;
- switch;
- textolite;
- solder and soldering iron.
A good device for scaring dogs can be made using this video:
Option 2
Ultrasonic device diagram two:
- constant resistors with a power of 0.25 W - five pieces;
- variable resistor;
- piezo emitter (for example, ZP-1, ZP-18, ZP-25);
- two transistors (type KT361B or 2T3307A, 2T3307V, KT3107);
- two ordinary ceramic capacitors;
- diode KD503A (protective);
- toggle switch;
- textolite;
- solder and soldering iron;
- a 9-volt Krona battery, a battery or a power supply with a voltage of 1.5 to 15 volts.
Another version of a homemade dog repeller is discussed in this video:
Manufacturing technologies
Option 1
Here we need only one microcircuit and five transistors. Two resistors, together with logic elements and capacitors, make up a rectangular pulse multivibrator with a frequency of one and a half hertz. And the second multivibrator, which already includes two other resistors and a capacitor, as well as the logical elements of the microcircuit, produces square pulses 20 kilohertz.
The output pulses are amplified by a transistor bridge that has a piezo emitter as a load. It can be replaced with a car piezo siren to increase the range.
As a housing, you can take the housing from an old VHF radio station.
Scheme for making a dog repeller
Option 2
Simpler, contains only thirteen elements. Five terminal resistors serve to reduce voltage and limit current. They also set the operating points for the two transistors that form the frequency circuit together with the capacitors.
A variable resistor regulates the ultrasonic frequency. We select it by power. The protective diode serves one purpose: it saves the device if the poles of the power source are accidentally reversed. Its voltage can be from 1.5 to 12 volts. The higher it is, the more powerful the emitted vibrations.