To protect your land from animals (and not only) you can use an electric fence, which is made of wire stretched on insulating posts or metal mesh, it does not come into contact with the ground, but is connected to a grounded source of high-voltage pulses. In relation to the life of animals or people, this does not pose a danger, but it gives a rather unpleasant and frightening feeling.
In order for the electric fence to perform only a repellent function, it is necessary to apply short high-voltage pulses to it, which are repeated at a certain interval.
You can make a pulse generator according to the circuit shown in Fig. 1. The generator is based on a ready-made high-voltage transformer; its role can be played by an ignition coil taken from a passenger car. The ignition coil is a transformer with a low-resistance primary and high-resistance secondary coils. When current ripples in the primary, pulses are formed on the secondary high voltage. In a car they go to the spark plugs, but here they go to the fence.
For the circuit to operate, a pulse voltage must be applied to the primary, which consists of intermittent bursts of pulses audio frequency, they are repeated after a certain period of time. The circuit for recreating these pulses is made using three 555 integrated timers.
Generators of infrasound and sound vibrations, respectively, were made based on timers A1 and AZ. Based on timer A2 - one-shot.
The current to the primary of the ignition coil T1 goes through the switch on the field-effect transistor LG 1. In order for a high voltage to form in the secondary T1, the current must pulsate in the primary. A sound pulse generator is made based on the AZ timer. When it works, audio frequency pulses from its output (pin 3) go to the gate of the transistor. As a result, a pulsating current is formed on the T1 primary, it induces a high alternating voltage on the secondary side.
The sound pulse generator is controlled by the level at pin 4 AZ. In order for the generator to operate at this pin, a logic one voltage is needed. At logical zero, the generator is blocked and its output is set to logical zero.
An infrasound generator is made based on the A1 timer; it generates pulses. The frequency of these pulses can be adjusted using variable resistor K1. The frequency of supplying high-voltage pulses to your fence depends on this generator. Pulses from pin 3 of A1 go to pin 2 of A2.
PCB
A one-shot circuit is made based on timer A2. Upon arrival of each pulse at pin 2, it forms one pulse of a given duration, which can be adjusted using variable resistor K4. This pulse signal goes through resistor B10 to the gate of a powerful switch field effect transistor UT1A in its stock circuit is connected to the primary of a standard automobile ignition coil T1. Almost any ignition coil can be used. It is better to use a coil from cars with a “contact” ignition system. For example, from Zhiguli VAZ - 2101 or 2106, from Moskvich 412 or 2140.
The basis of the article is taken from the magazine "RADIO CONSTRUCTION"
An electric shepherd or electric fence is a kind of device that is used for various purposes. It helps protect animals or protect against animals. The design of the ignition coil device is quite simple, so you can create it yourself. Strictly speaking, an electric shepherd is a generator that transmits current through a wire. Voltage helps scare away large animals, protect crops, or protect livestock from attacks by wild animals.
Why do you need an electric shepherd and how does it work?
- Metal wire, which makes up the main part of the fence.
- Generator, it transmits current through the wire.
The device of the electric shepherd is simple. The live wire does not allow the animal to leave the pen or go beyond its boundaries. If cattle are grazing in a certain place, the electric shepherd will not allow them to leave the pasture area. But you can see what a factory device for cows looks like.
Circuit and software component of the electric shepherd.
If cows graze freely, which is suitable for, then the fence will help protect crops, haystacks, flowers and other decorative plants from them.
On the video - why an electric shepherd is needed:
On some farms, such a fence is used to protect the feeders of other animals from pigs.
Electric shepherds are also used to protect their own plot of land from “encroachments and raids” by various animals. The fence is installed around the perimeter.
What is needed to create a device from an ignition coil with your own hands - diagram
- metal wire or mesh a (it should not touch the ground);
- pillars, capable of withstanding high voltage;
- grounded source high voltage pulses.
Do not be afraid that the current will harm a person or animal. The impulses will not cause harm and are not life-threatening. Contact with a fence is fraught with the occurrence of inconspicuous sensations and severe discomfort, which will scare away the animal, but will not cause significant harm to its health. Provided that all safety rules are followed. It may also be useful for you to know what this problem looks like and what can be done about it.
On the video - how to make equipment with your own hands:
Pros and cons
Among the advantages of a fence it is worth highlighting:
- Reliable protection from cattle raids and more.
- Relative ease of creation.
- Relatively low cost.
If you construct a fence yourself, problems may arise:
- with source material;
- with the diagram and its understanding.
It is advisable to have certain design skills; this will help to avoid mistakes when creating an electric shepherd. But what the symptoms of mastitis in cows may be will help you understand.
The principle of creating a homemade electrical device for shepherds for livestock
You will need an ignition coil. It will act as a voltage source and as a device that converts voltage into impulse. In order for the fence to only scare away livestock and not kill them, it is necessary to focus on the transmission of short impulses. They will be repeated at a certain frequency (interval). It is not difficult to make a generator if you take a completely finished transistor, which will transmit impulses or directly to the ignition coil from a passenger car. But what breeds of dairy cows there are and how to raise them correctly is indicated.
The ignition coil plays the role of a transformer; it is a device that performs 2 functions. The coil “gives birth” to voltage and converts it into impulses.
High voltage pulses in the car are transmitted to the spark plugs, and in the electric shepherd they are sent to the fence. What to do with mesh or wire, as well as poles, is very clear. After the structure is installed, it should be connected to the generator. You may also be interested in learning about what it looks like and what conditions exist for its maintenance.
Creating and connecting a generator
Step-by-step analysis of creating a generator:
- To obtain a voltage source, it is necessary to apply voltage to the “primary”; it consists of pulses formed in “packs” that are repeated with a certain periodicity.
- The pulses will be transmitted to 3 555 brand timers.
- If we take timers A1 and AZ as a basis, they can become a source of infrasound and sound vibrations.
- A one-shot monovibrator will be created based on timer A2.
- The voltage from the coil will flow to the “primary” T1 and go through the switch on the transistor.
- In order for the required voltage to appear on the “secondary” T1, it is necessary to ensure that the current pulsates on the “primary”, creating pulses.
- Based on the AZ timer, a generator was created that transmits sound pulses. When the timer is running, audio frequency pulses from its output (3) enter the gate of the transistor.
- As a result, it is possible to obtain the formation of a pulsating voltage on the “primary” T1, it is induced on the “secondary”, which makes it possible to obtain an alternating voltage on the “secondary”.
- Through the level at output 4 AZ it will be possible to control the generator. But in order for the generator to operate fully at this level, it is necessary to ensure the presence of a logical unit voltage.
- Logical zero will allow you to block the device and set the same indicator at the output of the generator.
- The A1 base will allow you to make a sound generator that will generate sound pulses. You can regulate the frequency of the pulses and configure them using resistor K1.
- Voltage in the form of pulses will go to outputs 2 A2 from pin 3 A1.
- The frequency of pulse transmission to the fence will depend on this device.
If we take the A2 timer circuit as a basis, we can create a one-shot circuit. When voltage is applied to pin 2, it will form a certain pulse, the duration of which can be selected independently using resistor number K4. This signal is in the nature of a pulse and will be sent to resistor B10. He hits the shutter key, field and enough powerful transistor UT1. In its stock circuit there will be a connection to the “primary” of a standard ignition coil from a T1 passenger car. You may also be interested in information about how to increase your milk yield.
It is worth noting that any ignition coil is suitable for creating a fence, but it is better to give preference to a car coil with a contact ignition system, such as the following cars:
- Moskvich 412;
- Moskvich 2140;
- Zhiguli 2106;
- Zhiguli 2101.
But you can find other suitable cars with contact coil ignition, which is suitable for creating an electric shepherd. But you can read how much hay a cow needs for the winter and what feed is the most effective.
Consequences of using electric drives for sheep and cows
It is advisable to choose a scheme with a short pulse, because if the pulse is long and quite powerful, the animal will not be able to leave the dangerous place. The unpredictable behavior of the animal (this rule applies to horses to a greater extent) is caused by muscle spasms. The spasm occurs due to too long and powerful an impulse. And if the animal does not leave the dangerous place, then a second impulse will follow and as a result of such an impact it may die.
For different types animals required various characteristics. Therefore, before starting to manufacture an electric fence, you should familiarize yourself with the related information.
Disadvantages of such a generator:
- It works constantly, consumes a lot of energy, which leads to rapid wear of the battery.
"represents the following design: the pasture is fenced with bare wire suspended on insulators. A voltage of 1.5...5 kV is supplied to it from a pulse generator. After touching the wire, the animal receives a nasty blow electric shock, of course, safe for his life.
After several touches, the animal develops a conditioned reflex, and it no longer tries to go beyond the fence. The current can be up to 15 mA (sinusoidal current with a frequency of 50 Hz), with short pulses the pulse generator current can increase to 500 mA. From a safety point of view, the pulse duration should not exceed 0.1 s, and the interval between pulses should be at least 0.75 s. In factory-made electric fences, the pulse duration is several milliseconds with a repetition rate of about 1 Hz, a voltage of 5 kV and a current of up to 300 mA ( electric charge up to 3 mC). Animals are most affected by pulses with a frequency of 250 Hz.
In Fig. 1.1,a shows the fundamental electrical diagram « electronic fence" This high voltage generator, producing a voltage of 1.6...2 kV with a frequency of 1 kHz. The voltage pulse appears once per second and lasts about 100 ms. It depends on the capacitance value of the capacitor C1 and resistor resistances R1, R3. The main part of the device is the transformer Tr1. It uses a ferrite core from a TV's horizontal scan transformer. The primary winding has 55 turns of PEV 0.71 wire and the secondary winding has 18 turns of PEV-1 0.25 wire. The third high-voltage winding is taken ready-made from the line transformer. You can wind the high-voltage winding yourself, but it is difficult. It consists of 1600 turns of insulated wire with a diameter of 0.12 mm, wound in layers of 100 turns each with layers of capacitor paper. For the fence, use copper or galvanized steel wire with a diameter of 1- 1.5 mm. It is stretched between the posts, which are placed every 25 m.
Rice. 1.1. "electric shepherd"
a - basic electrical diagram (L1- 55 turns PEV 0.71; L2- 18 turns
PEV 0.26; L3- 1600 turns PEV 0.12; b -TV line transformer
converted to work in a generator.
Rice. 1.2. "Electronic fence":
o - wire fencing design; b - insulators for a portable fence.
Insulators - high-voltage insulators from power lines, or, in extreme cases, ordinary, porcelain. Insulators for portable fences can be made from plastic or glass bottles (Fig. 1.2, b) mounted on wooden stakes driven into the ground. Fence wire wraps around the neck of each bottle. It should not touch bushes, grass, etc. It is necessary to pay attention to good quality grounding. The ground is used as the second wire of the high voltage line. Distances between fence wire and ground for various cases shown in Fig. 17.8, A.
Setting up the device consists of obtaining the maximum voltage at the output of the pulse generator. The magnitude of the voltage is judged by the length of the spark that is formed between the output terminal of the generator and the wire connected to the ground. Adjustment is made using variable resistors R1 and R2.
It is necessary to follow safety rules and under no circumstances touch exposed wires!
The operation of the device is checked by carefully bringing your hand to the wire; at a distance of 10 mm to the wire, a spark should jump with a dry crackle of a discharge, and a slight tingling sensation will be felt. Animals come under voltage at a distance of 2...4 mm. The fenced area is 5...10 hectares.
A few words about the benefits "electric shepherds" The fencing allows for more animals to be grazed than usual. This gives a 20...25% increase in milk or meat production. The fence protects farms and gardens from the invasion of uninvited four-legged guests.
A device such as an electric shepherd (a mobile electric fence on a pasture site) allows grazing of various types of farm animals or poultry without direct human intervention. Cattle grazing freely inside a fenced area do not suffer as much from blood-sucking insects as they do when tied. The electrical wire protects the livestock from attacks by predators. Electric fences are also used to protect crop areas or hay reserves from damage. You can also protect dangerous areas of the landscape (ditches, ravines) with a similar fence.
An industrial electric shepherd is quite expensive equipment. But if you want to save money, you can make it yourself at home.
- metal;
- wood;
- polymer materials.
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How the device works
An electric shepherd is a device that is a generator operating from a 220 volt network (or from battery 10-12 volts) and transmitting current pulses to a bare wire stretched over the insulators of the support posts. The wire fences off the area within which animals graze.
When you touch it, a current discharge passes through the animal’s body and goes into the soil to the grounding part of the device. A low-power discharge is not capable of causing harm to the body, but causes discomfort in the animal. The reflex to avoid the wire is developed very quickly.
DIY electric shepherd
Making an electric shepherd for animals (cattle, pigs, sheep, goats) with your own hands is a task that even a novice radio amateur can handle.
Most of the components necessary for this can be found on the farm. What you can't find will have to be purchased.
Support posts
First you need to decide which area around the perimeter needs to be fenced. The maximum distance between two support posts should not exceed ten meters (if the animals are large and active, then even less).
To find out how many support posts you will need, you should divide the perimeter of the site by the distance between them. A homemade electric shepherd can have support posts made from:
Metal posts (pins sharpened at one end) are heavy, but easy to drive into the ground. Those cut from wood will be cheap, but fixing them in the ground will not be easy; you will have to dig them in. Ready-made posts made of polymer materials, purchased in a store, are an expensive pleasure.
The height of the support posts is selected depending on the type of animal for which the electronic shepherd is being made.
Insulators
Each support post must have an insulator to which the wire will be attached. Industrially produced insulators sometimes appear on sale. It would be good if they were ceramic.
You can make insulators with your own hands. A good insulator will be made from plastic bottle without bottom. It is put on a post, and several turns of wire are made around the neck.
Wire
The wire must be resistant to adverse environmental factors. Iron will quickly rust. Galvanized with a diameter of 2 mm is suitable.
The bare wire itself is difficult for animals to see, so it is worth using it in combination with brightly colored ribbons. A warning message for people is also necessary.
Generator and grounding
You can purchase a ready-made electronic fence pulse generator, but with some experience it is not difficult to assemble it yourself from an ignition coil and three 555 timers.
If an experienced radio amateur gets down to business, this scheme may be somewhat simplified or supplemented.
Convenient to use as grounding iron rod(one or more) with a length of at least 120 cm. The grounding goes 1 m deep into the soil. In dry weather for better electrical conductivity The soil around the grounding must be shed generously with water.
