Do-it-yourself ultrasonic dog repeller project. How to make a dog repeller with your own hands: several simple options

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.

Bread 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.

(ultrasonic repeller) produces a sound signal that does not harm dogs, but causes them discomfort. A person does not hear this signal, because its frequency is above the threshold of audibility for a person. The device produces sound at a level of 100 dB at a distance of 1 m.

The circuit uses a standard 555 timer, on the basis of which an oscillator is assembled, tuned to a frequency of 25 kHz. With resistor R3, the generator is tuned to the resonant frequency of the piezo emitter you are using.

Rice. 1 Ultrasonic dog repeller, scheme

About the autotransformer.

To obtain maximum output from the piezo emitter (B1), an increased alternating voltage must be supplied to it. This is achieved by connecting B1 through autotransformer T1.
An autotransformer can be made independently using iron from an output or matching transformer used in small-sized radio receivers.

For piezo emitter type 250ST180 (voltage with amplitude of at least 25 V). We remove the windings present in the transformer, and in their place we wind 100+800 turns with PEV wire with a diameter of 0.1 mm.
It is also convenient to use a transformer from old telephone models as T1. You only need to remove the top winding and instead wind 100... 150 turns with the same wire. The number of turns in the winding (2-3) depends on the supply voltage of the circuit and is taken to be maximum at Upit = 9...12 V.

The ultrasonic model sends high-power ultrasound signals towards the dog. Ultrasound has a depressing effect on dogs, forcing them to turn around and even run away, while the device is completely safe for humans. As the dog approaches, the signal intensifies and the animal begins to feel discomfort. The device is compact and can be carried with you in a bag or pocket. As the animal approaches, it will react and the signal will increase. With a repeller, a whole pack of dogs is not scary, which is very convenient; you can do without blood and victims. There are a lot of electrical diagrams for this device on the Internet, so if necessary, you can assemble it yourself and buy the components at any radio store. The device is quite simple, and it will cost you much less.
An electric device or stun gun is no less popular. It’s also compact, and when you press the button it produces a characteristic crackling sound, which means that ozone is released, which is unpleasant to a dog’s sense of touch. The device is dangerous for an approaching dog; if the distance decreases, it can give an electric shock and temporarily paralyze. The device will also force the dog to open its jaws if the dog still grabs you.
Gas in the form of a gas canister with a chemical filler inside. When buying a spray can, pay attention to its technical characteristics, since not all products are effective; if a dog attacks, the product may simply fail. When sprayed, the dog should rush, run away and no longer show aggression. In principle, you can build a gas pistol yourself by filling the cartridges with red hot pepper. You can leave the device idle. Sound is effective against dogs; the device can also be made with a light signal reflector.
Repeller - smell. Everyone knows that dogs have an excellent sense of smell and they do not at all like, for example, the smell of medical or isopropylene alcohol. All you have to do is wet the tampon. But this method has a big disadvantage - the alcohol evaporates quickly, which means you need to carry it with you at all times when going outside. Hot capsicums are irritating to the dog's nose, skin, and eyes, as is the smell of lemon, orange, and vinegar.

Principle of operation

Inside the body of the ultrasonic repeller there is a generator with an electrical circuit and high-frequency pulses, thanks to which the signal propagates. The device is equipped with a power source; simple models run on batteries.

Devices can be stationary or portable. In the first case, they are installed on the object and begin to operate when the dog approaches the object. In the second case, you can carry it with you to avoid encounters with aggressive animals.

Advantages and disadvantages

The undoubted advantage of all repellent devices is their safety for humans, as well as:

Instant exposure of an animal to an ultrasonic or electronic device.
Convenient to use, just remove the pocket from the case, or press the button found on all modern devices.
High efficiency of devices.
The efficiency of the devices regardless of the time of day and weather conditions.
Compact dimensions of protective devices.
No skill required to use.
They begin to act at a distance of 25-30 meters.

How to make your own ultrasonic

To assemble an ultrasonic model, you need to select a microcircuit and 5 transistors.

1. Description of the circuit

This foreign scheme consists of:

Standard timer 555, frequency 40 kHz.
Amplifier based on transistors TP1.
Timer 555 IC2, generating an antiphase signal.
Ultrasonic transducer.
Power switch in the form of a button.
Lead-acid battery when using the device in stationary mode.

Required materials and tools:

You will need a piezo emitter for assembly; you can borrow them from the dynamics of old speakers, a music box, or a calculator.
The case can be taken from a radio that has failed Chinese equipment.
9V batteries
Transistors type KTV816
Diode printed circuit board
Piezosiren, suitable for a car
Oscilloscope
Indicator, LEDs
Resistor, suitable from an old TV.

Step by step guide:

Assemble the generator.
Adjust the frequency using resistor R3; the output of the circuit should produce 2 antiphase signals, frequency 25 kHz3.
Connect the emitter to the choke.
Connect a voltage of 5.6 V through a zener diode, LED D2.
Connect an indicator for low battery, and LED D3 to turn on the device.
Set the frequency to 25 kHz with resistor P35.
Check the operation of the pulses on the emitter using an oscilloscope.
If the assembly option is stationary, use more emitters in the device, up to 10 pcs.
Install powerful IRF640 transistors along the way.

How to make an electronic repeller

With the slightest knowledge of electronics, assembling the device is not at all difficult. Large financial costs will not be required either. You need to purchase a microcircuit and transistors. To regulate the frequency of sound, it will be necessary to create an additional unit consisting of resistors, transistors and diodes designed for protection in case of polarity reversal.
After assembling the device, you need to check the resistance of the resistors so that the load is applied to them evenly; additional installation of a piezoceramic emitter will be required.
Power supply for the repeller is a standard crown, voltage -9 V.
The LED flashlight is built into the front of the housing.
To increase the power, it is advisable to install 8 batteries (AAA standard), capacity 300 mAh, under the crown.
The essence of the electronic device is the activation of a high-frequency pulse generator when a dog approaches. The frequency is not perceptible to humans, but animals hear the noise of the generator very well.

Do not experiment with the device on your pets; if you point the repeller at them, you may lose their trust in the future.
Set the frequency recommended by the manufacturer; if it is exceeded, the device will quickly fail.
Typically the device is designed for a range of 30 meters, which will prevent the animal from invading your territory.
When choosing a finished device, pay attention to the cost, ease of design, quality of all components, manufacturer’s brand, and production technology.
Please note that cheap devices may be ineffective, unreliable, and may not meet the parameters specified in the documentation.
Choose an acceptable type of device in advance; if you carry it in your pocket, it is better to buy a portable model. If you need to install it on a tree or wall, choose a stationary device.
Cobra is considered a new and high-quality model with 4 operating modes; it can be used as a security system. A small pocket device - Osa, costs only 1200-1500 rubles, is effective and convenient to carry in your pocket.
The ultrasonic device with a power of 130 dB is distinguished by high volume. At a distance of 1 meter for a dog, this is the noise of a jet plane, the effect on the animal is simply deafening, thereby you can put it in an aggressive state, you will only make things worse for yourself in particular.
Do not rush to use the device if the dog is calm and does not at all seek to harm you.
A distance of 4-15 meters is considered large for the repeller to work effectively; it may simply not have an effect on the animal and lose its power at a distance. Consider the range of the device when purchasing or designing a model yourself.
Do not panic when an animal approaches, do not make sudden movements. Keep your finger on the button; when attacking, it is better to let the predator get closer, the noise will be deafening, and the shorter the distance, the more effective the device will be.
Do not play with the repeller, do not turn it on unnecessarily, for example, pointing it at a quiet, innocent dog.
13.Do not let children play with the device; it is better to teach them how to handle it correctly.
Don’t be a provocateur by turning your pet against you; with the device turned on, you can provoke aggression, but why would you want to do that?

A dog repeller is a useful device in the everyday life of a modern person. What is it for?

The problem of people living close to wild animals in cities is becoming increasingly urgent. Due to the abundance of food, dogs actively reproduce, gather in packs and begin to defend their habitat, demonstrating their direct aggression to passers-by. First of all, children who, due to their short stature, are not considered by predators as serious competitors are at risk. Having survived a wild animal attack once, a child receives psychological trauma for the rest of his life. Even adults experience painful treatment after bites. To combat the danger of attack, scientists have developed a dog repellent device that has proven itself in a variety of situations.

A dog repeller is a useful device in the everyday life of a modern person.

Operating principle

An ultrasonic device emits a directed sound signal towards the animal. To prevent a person from feeling discomfort, the frequency of the signal is higher than the human ear can hear. The dog hears a sharp sound, which intensifies as it approaches. As a result, the dog begins to panic from fright and runs away. The range of the device is 15-20 m. The most powerful models have an effect at 30 m.

Since an ultrasonic dog repeller uses sound, the device will not always work, particularly if the animal is deaf, has rabies, or has drooping ears. In addition, it may not work on trained dogs either.

You should also not use the device on calm animals, as this may anger them.

For additional protection, a special device is installed on the ultrasonic dog repeller - a powerful LED flashlight. It will blind the dog and help drive it away if the scaring sound does not work.

The problem of people living close to wild animals in cities is becoming increasingly urgent

The electronic dog repeller is powered by batteries. They need to be changed without waiting for discharge, as this affects the power.

Comparison of dog repellers (video)

Methods of protection

To scare away wild and feral animals, various means are used. For example, a stationary ultrasonic dog repeller is used to protect houses and areas. The device allows you to leave your cottage or garden plot unattended while the owners are away. The operation scheme is similar to a portable device. Power is supplied from the network, and it starts working when the motion sensor is triggered. In addition to dogs, the device works as a repeller for cats, foxes, and rodents. The frequency of the sound changes so that the animals do not get used to it and continue to be afraid to enter the territory.

Most devices do not have a noticeable effect on humans. The most powerful models can cause headaches and ringing in the ears.

Electric shock is effectively used as a repeller. The sharp sound of the discharge and flash with the release of a large amount of ozone scare animals already at a distance of 10-20 m. It is often installed on a bicycle so as not to reach it while moving.

Batteries power the electronic dog repeller

In addition to electronic ones, more traditional means of repelling dogs are also used, in particular, repellents and mixtures. The way they work is simple - they emit an unpleasant odor. After treating the area around the perimeter, animals will stop entering it. There is also a dog and cat version.

For tourists and athletes, it may be important to make a homemade dog repeller. It is an analogue of a gas cylinder. Consists of a container into which a mixture of vinegar and pepper is placed. This option is inhumane, but very effective. Other mixtures are also used, in particular, based on shag.

You can make a homemade ultrasonic repeller if you don’t trust the effectiveness of the devices being sold. This will require some knowledge of electrical engineering.

Sometimes the best defense is an attack. If you don’t have the device at hand, and you are surrounded by an angry flock, you can simply bend down to the ground and pretend that you are picking up and throwing a stone. This technique will scare away the dogs. Dogs are animals, they are devoid of reason, and instinct makes them afraid of such gestures.

Application area

You can use ultrasound to scare dogs away in different ways: to protect yourself, your family, your home or your garden. When walking with your dog, you can protect it from attack. In addition, the device allows you to train the animal, making it obedient.

You need to remember the rules for working with the device. The battery must always be charged. The device should be aimed at an aggressive animal with a deviation of no more than 5°. If the sound does not work, do not forget to turn on the flashlight.

From the moment of collision, you have literally a few seconds to use your repeller. Therefore, you need to carry it in your pocket. You can use the device without taking it out of your clothes; you just need to press the button.

Do not provoke the animal's aggression. The best way to avoid an attack is to stay away from the source of danger.

How to make a dog repeller (video)

Conclusion

Whether to use personal protective equipment is up to everyone to decide for themselves. Children, athletes, tourists are the main victims of attacks. If you are afraid, then you should buy such a device. The presence of a repeller does not mean that it will certainly be used; it may not be useful to you at all. However, the device gives a feeling of confidence and security, and therefore psychological comfort. And it’s not so important whether it’s a dog repeller, made with your own hands or bought in a store. The main thing is that the device makes it possible to avoid injuries and unpleasant consequences from a bite.

Attention, TODAY only!

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.