How to make an ultrasonic repeller for mice, rats and other rodents with your own hands. Homemade mole and shrew repeller New schemes for rodent repellers
In this article we will talk about a do-it-yourself ultrasonic rodent repeller.
With the onset of cold weather, mice that ran through the fields in the summer, in winter, in search of food and warmth, run indoors - livestock farms, private houses, and barns. You can still fight mice different ways, but if a person is faced with the pest activity of rats, then this really becomes a problem. They are omnivores, capable of spoiling food supplies, and pose a threat to humans as carriers of epidemics. The main problem in dealing with rats is that they are very cunning. If rats need to get food for themselves, they unite into a “team” in which each animal performs a specific task. Most often they “work” in pairs. One of my work colleagues told me how he tried to catch rats using a simple trap. He accidentally saw two rats steal the bait from the trap. One rat lifted the trap's strut with its teeth, lowering it to former place after the other one pulled out the bait. Rats are so adaptable various conditions that it is almost impossible to get rid of them. It’s not just that they say that after a nuclear war only cockroaches and rats will survive.
Faced with the harmful activity of rats, I decided to build an ultrasonic rodent repeller. First, I scoured the Internet trying to find information about the effectiveness of these ultrasonic generators.
Knowing and Once again Having made sure that the Internet is “teeming” with advertising intended not only for honest sales, but also for “selling” unnecessary goods, I began to look for information about the parameters and diagrams of ultrasonic rodent repellers. When it comes to choosing frequencies, all sources write differently. Only the circuits of ultrasonic repellers and the principles of their operation are basically the same.
Various sources provide various options ultrasonic frequencies repelling rodents: 15...40 kHz, 16...28 kHz, 25...50 kHz, etc.
To prevent rodents from adapting to ultrasonic frequencies, modulation is used with ultrasound interruption at frequencies: 2...10 Hz, 6...9 Hz, 10...30 Hz. In fact, it’s more logical to write not “adapted”, but “got used to it.” Imagine that a kettle is boiling in your kitchen with a whistle, and you are in the room, so the sound of the kettle is not very loud. Conduct an experiment - do not turn off the kettle immediately. After a while you will feel that you do not notice his whistle. This happens because the sound of the kettle whistle is continuous. Now imagine the whistle of a sports referee. His whistle is much more attention-grabbing than a teapot's whistle because there is a ball inside the referee's whistle that interrupts the sound of the whistle. Remove the ball from the whistle and the sound of the whistle will become less sensitive. Think about why an electric alarm clock not only beeps, but beeps? It is the interruption of the sound created by the modulator that does not allow you to get used to it. That's why the beeping alarm clock makes you wake up.
Now let's touch on the issue of adaptation to ultrasound. To prevent rats from adapting, it is proposed to change the frequency of the ultrasonic generator 2-3 times a week. It's logical. But doing this using switches is not very convenient. But what about “mother laziness”? Therefore, schemes with automatic change of ultrasonic frequency are proposed. But all schemes with automatic frequency change published on the Internet operate only at one or two ultrasonic frequencies. I’m not a rodent, so I can’t speak about the effectiveness of dual-frequency circuits, but after carefully reviewing the proposed circuits, finding “jambs” or shortcomings in almost all of them, I decided, by slightly modifying one of the circuits, to make my own “universal” circuit of a four-frequency ultrasonic repeller rodents
As a “raw material” I took the following diagram ultrasonic generator, which automatically changes the frequencies of the modulating and the ultrasonic generator itself.
The ultrasonic generator is made on elements DD1.3 and DD1.4. It is modulated by a generator made on elements DD1.1 and DD1.2.
The frequency change control circuit consists of a generator on a DD2 chip operating with a frequency of 0.2...0.3 Hz and switches VT1, VT2. The switches operate in antiphase, changing the parameters of the timing circuits of the generators and thereby their frequency. The operating frequency of the generator on DD1.1, DD1.2 is 15…20 Hz, and the generator on DD1.3, DD1.4 is 40 kHz.
What is this device? The above circuit works at only two frequencies, and not “correctly”. When the circuit operates, it is not the oscillation frequency that changes, but only the duration of the positive pulses of the high-frequency oscillation of the multivibrator - the duty cycle. However, the change is insignificant – no more than 10%. This change occurs spasmodically, so if it turns out that you have set the frequency of the ultrasonic generator to a frequency that is not “unpleasant” for rodents, then your repeller will be absolutely useless. Controlling the frequency of an ultrasonic generator and modulator with one control circuit is generally stupid. Moreover, I did not see any anti-rodent adaptation function in this design.
I propose another ultrasonic rodent repeller scheme that I developed, which is a little more complicated, and in my opinion should be more effective than anything I could find on the Internet. Schematic diagram The ultrasonic rodent repeller developed and implemented by me in practice is presented below.
The ultrasonic signal generator is made on the D3 chip and elements D1.3 and D1.4. The generator operates in the frequency range from 13 to 50 kHz. This range is divided into 10 sub-bands, which can be manually selected using switch SA1. The use of an operational amplifier made it possible to implement electronic regulation not by the duty cycle of the signal, but by its frequency, which in other Internet circuits of ultrasonic repellers is realized only by significantly complicating the circuits.
The ultrasonic rodent repeller circuit has three modulators:
1. The modulator, made on elements D1.1 and D1.2, operates with a signal interruption frequency of 1 minute. Of which 45 seconds ultrasonic generator works, and is silent for 15 seconds. These time intervals are determined by the rating and properties of the electrolytic capacitor. This type of modulation is used to prevent rodents from getting used to ultrasound as such.
2. A modulator made on elements D2.1 and D2.2, which changes the frequency of the ultrasound generator with a frequency of 20 minutes. The frequency changes abruptly, within 5 kHz. This type of modulation is used to prevent rodents from becoming accustomed to specific ultrasound frequencies.
3. The modulator, made on elements D2.3 and D2.4, smoothly changes the frequency of the ultrasound generator within 5 kHz with a change frequency of 1 Hz, like a sports referee’s whistle. There is a “sliding” of the ultrasound frequency “down and up”. Of all the types of modulation, this creates the most unpleasant effect.
Without promptly changing frequencies using the SA1 switch, the ultrasonic repeller actually undergoes a simultaneous smooth and abrupt change in the oscillation frequency within 10 kHz. And since the modulators operate at their own frequency, and there is a smooth, non-fixed sliding of the ultrasound frequency, rodents will not like it in any case. Switch SA1 allows you to select the sub-range of ultrasonic frequencies that will be most effective in repelling rodents. Its use was a consequence of the fact that I could not find accurate information about what frequency range actually affects rodents. Therefore, by selecting a sub-band, it becomes possible to determine those frequencies that repel rodents as much as possible.
About the design and elements of the circuit.
The entire structure is assembled in a housing from a wireless apartment bell. Appearance You can see a working generator in the photo above. All elements of the device are fixed inside the case using glue gun(see photo).
The D2 chip can be replaced with a 561LE5. Transistor VT3 can be replaced with KT315B (G). Transistor VT4 can be replaced with KT361B (G).
Almost all ultrasonic rodent repellers use a high-frequency dynamic head as an emitter. The coil resistance of such a head is very low, which leads to an increase in current consumption. And the ultrasound radiation from it is weak due to the fact that ultrasound is at the cutoff of the frequency range of the high-frequency dynamic head. I suggest using an ultrasonic piezo emitter. Domestic piezo emitters such as ZP-1 or ZP-3 are not suitable for this - the radiation power is weak, so I suggest using more powerful imported types AK-059, AK-157, or other similar ones. Since the ultrasonic piezo emitter is not an inductance, like a dynamic head, but a capacitance that must be charged and discharged, a push-pull balanced current amplifier assembled on transistors VT3-VT6 is used as the output stage.
To power the ultrasonic repeller from a mains voltage of 220 volts, a transformerless power supply circuit has been introduced. Current consumption from the network is about 30 milliamps. Since the circuit does not consume much current, it can be connected either directly to an outlet or to the contacts of a light switch in a room. Thus, when leaving the room, you turn off the light, which turns on the ultrasonic rodent repeller, and when you enter and turn on the light, the contacts close and the repeller turns off. This is very convenient for basements and cellars.
Capacitor C18 must be designed for 400 volts. Rectifier diodes VD1 - VD4 - any rectifier, for a reverse voltage of at least 400 volts. Electrolytic capacitors - for an operating voltage of at least 10 volts. Instead of the D814B zener diode, we can use any other one with a stabilization voltage of 9 volts.
The ultrasonic repeller circuit was repeatedly changed and refined during assembly, adjustment and testing, so it was assembled on two printed circuit boards with a large number of jumpers and cut conductors. Some of the elements are mounted in the housing using wall-mounted installation. This is clearly visible in the photograph. Therefore, there is no point in offering you the “wrong” printed circuit board with the placement of elements.
Everywhere they write that the generator has a negative effect on nervous system humans and animals. Therefore, after turning it on, you must leave the premises and remove pets from it. During setup and testing, I did not feel any negative impact. At higher frequencies - nothing at all, but at lower frequencies, the vibrations are very unpleasant to the ear. It’s as if there’s something noisy and some heaviness in the head, not in the ears. In complete silence, the whistle is also felt in neighboring rooms, and it is not possible to determine the location of the ultrasound source with the ears.
At first, my cat didn’t react at all, but when generating in the range of 16-26 kHz, he lay down for a while, and then went into another room and didn’t come back at all for 24 hours.
Today there are already enough a large number of various methods and means of controlling pests that have appeared on the site.
Mechanical structures also include traps, mousetraps and special molebreakers, which have a very good effect. Sometimes on the site you can find special devices against moles, made according to homemade schemes. 
The last type of mole and rat repeller is electronic devices. For ultrasonic repellers interesting way actions. It is very effective, safe for humans and at the same time humane. The devices will emit low frequency sound, to which burrowing animals and rodents are very sensitive. They affect the nervous system and irritate the ears, so pests try to leave the unfavorable place faster. An ultrasonic mole repeller is considered a more universal type of device than other types. 
Mole repellers according to these schemes have a wide variety, and everyone will have the opportunity to choose the most suitable one for themselves. You can also make a mole and rodent repeller with your own hands according to a certain pattern.
Video “Modern repellers”
From the video you will learn about modern methods fighting moles,
Repeller made from plastic bottles
If the owners decide to make a repellent device themselves, then it is advisable to use ready-made diagrams, which describes such designs in detail. So how to make a grotto and rodent repeller with your own hands?
To make a mole repeller with your own hands, you need to choose the scheme according to which you want to arrange the structure. Very popular now simple circuits, which involve the use of plastic bottles.
First you need to take empty plastic bottles, several sticks or hollow tubes about one and a half meters long. Then you need to take a sharp knife or blade and cut holes in the body of the plastic bottles so that after the cuts you can pull out the plastic blades. They are pulled out and bent in different directions to let more air into the bottle. Then you need to drill a hole in the bottom. A pin or hollow tube will be inserted into this hole. Thus, according to this scheme, we will get a pin with a bottle attached, which looks like a feeder. Bottom part The pin plunges 30 centimeters into the ground. 
Visually, such a repeller is not very aesthetic, so it can be painted in bright colors. Of course, this will not increase efficiency. This mole repeller scheme is the simplest.
A more powerful analogue will not be a feeder, but a propeller. The propeller will rotate like a windmill under the influence of the wind. When placing 3-4 plastic bottles on it, it will make much more noise, and moles will not come into your area.
You need to make 2-3 holes in the walls of the bottle and insert light, wide plastic parts into them to make a primitive propeller. Then make a hole in the bottle cap with a nail and attach it to the pin. The mechanism of action is the same as in the first case.
Such repellers operate on the principle of a wind generator. In design air currents create a loud noise that will transmit vibration vibrations into the ground through a hollow tube or pin.
Traps, traps and molebreakers
The use of mole traps practically does not have the desired effect. To hunt moles, summer residents use various traps:
- Three-liter jars are buried below the tunnel level, usually 70-100 centimeters, and installed vertically, with the neck up. When moving, the mole simply falls into the jar and cannot get out;
- install galvanized pipes in the burrows, equipped with doors on both sides. To set a trap upper layer The soil near the hole is dug up and the device is placed directly into the tunnel. The doors are designed in such a way that they open only in one direction.
Most mole traps have smooth walls. When moving, the mole clings to the ground with its claws. Accordingly, he will not be able to climb into a smooth-walled trap. 
Traps are capable of catching any animal that has settled on plot of land farmer Despite great physical strength, a mole is unable to escape from a trap. It is enough to leave a good bait with a strong smell, and after a few days the trap should work.
However, do not forget that installing traps poses a great threat to your pets or your neighbors' pets. On the property you can often find other people's cats who do not recognize the division of territory by fences, and they can become victims.
Chemical control agents
This method of controlling various pests is effective, but not humane. The chemicals are scattered around the garden where signs of moles are usually found. If they eat poison, they may die within a day. They even began to use arsenic against moles because of its high level of toxic substances. 
There are plenty of traditional means to control rodents. Among them are poisons, baits, mousetraps. They are effective, but not suitable for use in homes with small children and animals. You can get rid of mice and rats using an ultrasonic repeller. These devices belong to the latest methods home pest control.
How it works
The rat and mouse repeller emits sounds at high frequencies that are not perceived by people, but rodents feel ultrasonic waves.
The purpose of the device is to create sound vibrations with frequencies and power that are perceived by rats and mice (frequencies from 30 to 70 kHz).
Most repellers emit only ultrasonic waves, but there are also those that also produce electromagnetic radiation.
Ultrasound devices can only act on an area separate room, since ultrasonic waves do not pass through walls and floors. Electromagnetic radiation penetrates walls; obstacles to them are metal plates and objects.
Ultrasound, reaching any surface, is reflected from it. From this we can conclude that one ultrasonic repeller for several rooms in the house will not be enough. There are a large number of such devices on sale, but they are not cheap, so it is more economical to assemble such a device yourself.
We make a device at home that frightens pests
The creation of such devices does not require special skills or special knowledge; any novice radio amateur will be able to assemble them with his own hands, based on the included instructions and diagrams.
For this you will need:
- regular soldering iron,
- parts R7, R5, C6, C5, DD1.3, DD1.4.
Using a soldering iron, a symmetrical multivibrator is assembled from parts; it is the basis of the entire device.
Frequencies emitted ultrasonic waves can be adjusted by adjusting the generator. The signals emitted by the generator are fed to a device that amplifies their power.
The emission of ultrasonic waves occurs due to the operation of the Sp1 element.
To assemble a more complex device with your own hands, capable of constantly automatically changing the range of ultrasonic vibrations, you will need more high level craftsmanship and skills. You can do it based on the proposed scheme:
Modulation of the frequency of the emitted ultrasound occurs after a certain time interval. Setting up the device is carried out in stages and begins with determining the operating frequency of the generating element.
What you should know
When assembling a device of this type, you should not expect that you will be able to get rid of rodents as soon as the device is connected and starts working.
In kitchens and pantries, where there is something to profit from small pests, it is worth installing appliances that are more powerful than in other rooms. In such premises, the fight against mice and rats can take even two months. Where there is no food available, the process will go much faster and will take about two weeks.
To combat rodents in unheated basements and storerooms, you need to assemble a device using radio components that can function at subzero temperatures.
Pets can sense some of the frequencies emitted by the repeller. In this case, they feel anxious. In order for pets to stop feeling the effects of ultrasound, it is necessary to change the frequency of vibrations emitted by the device. If such actions do not lead to the desired result, you will have to purchase a factory-made one. True, many devices domestic producers They also work at frequencies audible by pets, but there are models from foreign brands that do not affect animals.
Each device is capable of protecting a certain area of the room based on its rated power. However, mathematical calculations made using formulas attached to the diagrams may result in an indicator that does not take into account the load of the room with furniture or other obstacles that reflect ultrasound. Therefore, it is necessary to make an adjustment, taking into account the characteristics of the room where the device will operate.
After studying the reviews of people who have already used purchased and homemade devices, you can decide on your choice. Of course, you can make such a device with your own hands using circuit diagrams and necessary elements from a radio store, but this requires certain knowledge.
The described design uses the principle of creating vibrations in the ground to scare away rodents - this alarms them and they leave in search of quieter places. One of simple ways To create vibrations is to stick wooden or metal pins into the ground with wind vanes attached to them. But you can try to use “electronics” and use a vibration motor instead of a windmill. No special power is required here, and for better efficiency and coverage of a larger area, it is enough to increase the number of such repellers. As vibration motors, you can use either ready-made “vibration alerts” from cell phones, or more powerful, but requiring little modification, low-voltage motors from old cassette recorders or car radios (the modification itself consists of attaching a small eccentric to the shaft).
The simplest version of this design is to take a 6-12 V battery and connect several vibration motors to it ( Fig.1). The battery must be of appropriate capacity and should be enough for several days of operation. Of course, you can take several batteries and change them as they are discharged, or simply connect each battery to its own vibration motor - in this option less problems with wires.
For even more economical use battery, you should assemble a motor control circuit that ensures their intermittent operation - for example, turning on for 0.2...0.5 seconds after pauses of several seconds. On Figure 2– photo at the stage of prototyping such a circuit, on Figure 3– the resulting circuit for controlling one vibration motor.
The principle of operation of the circuit is simple - a generator with a changed duty cycle of pulses is assembled on elements DD1.1, DD1.2 and DD1.3 (approximate timing characteristics are shown in Figure 4). The frequency and duration of the pulses can be selected within a wide range by selecting the values of capacitor C1 and resistors R2 and R3.
Element DD1.4 is a buffer, the voltage from its output is supplied to an emitter follower assembled on transistor VT1, the load of which is motor M. Resistor R5 is current-limiting, its resistance and overall power dissipation are selected based on the electrical parameters of the motor. Diode VD3 protects the transistor from reverse polarity pulses that may appear if the motor shaft continues to rotate by inertia with the transistor already closed. When using the motor shown in Figure 5, no such impulses occurred (two such engines were removed from an old car radio).
The +12 V supply voltage is supplied to the circuit through the VD4 diode - this is a kind of protection against accidental polarity reversal when connecting the wires to the battery. Capacitor C2 acts as a noise suppression capacitor, C3 as a storage capacitor (smoothes out ripples in the power supply when the engine is running).
The maximum current consumption of the circuit when using the shown motor reaches 90...100 mA at the moment of rotation. Therefore, in the case of large current consumption, in place of transistor VT1, you should install either a high-power composite transistor (for example, KT829) or assemble it from two as shown in Figure 6. The capacitance of capacitor C3 should be increased to 330...1000 μF, and the value of resistor R5 should be reduced.
As mentioned above, motors from the tape drive mechanism of the car radio, as well as from an old Soviet tape recorder and from a CD drive were used as vibration motors. M5-M6 nuts, short, were used as an eccentric metal racks and self-tapping screws of approximately the same mass (visible on Fig.5). All this was glued to the motor shafts with hot glue and then wrapped with insulating tape. "Vibrate alert" from cell phone was also tested and everything worked fine, but it was not used in the repeller, since it was planned to be used in other experiments.
All these repellers ( Fig.7) were collected at the request of a neighboring summer resident. Then, after a while, he asked to collect a few more pieces - it turns out that the moles that were bothering him went to neighboring dachas and now their owners also have something to do. As can be seen in the figure, vibration motors and electronics boards were placed in suitable sized plastic cases and secured to wooden and metal pins (the metal ones are the remains of the “thresholds”, about 60...70 cm long). The neighbor says that he also covered them with cut in half plastic bottles– this is both protection from rain and receiving additional vibration from the fact that the bottles are blown by the wind.
Attached to the text are files of the layout of two versions of printed circuit boards in program format - one option for wall-mounted output parts, the second – with partial use SMD components. The pattern of the “low-current” SMD version is drawn from the print side and when used you will need to turn on the “mirror” mode.
Andrey Goltsov, r9o-11, Iskitim, summer 2017
List of radioelements
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad | |
|---|---|---|---|---|---|---|---|
| Figure No. 3 | |||||||
| DD1 | Digital microcircuit | K561LN2 | 1 | To notepad | |||
| VT1 | Bipolar transistor | KT315B | 1 | To notepad | |||
| VD1, VD2, VD3, VD4 | Rectifier diode | 1N4002 | 4 | To notepad | |||
| R1 | Resistor | 10 kOhm | 1 | To notepad | |||
| R2 | Resistor | 200 kOhm | 1 | To notepad | |||
| R3 | Resistor | 5.1 MOhm | 1 | To notepad | |||
| R4 | Resistor | ||||||
The diagram of the ultrasonic repeller is shown below:
The sound-reproducing element of the device is a piezo emitter (ZP-1, ZP-3, ZP25... in general, any). With a slight modernization of the device, you can increase its power by adding a simple ULF and using a high-frequency speaker.
Operation of an ultrasonic repellent device. Diode VD1 is needed to protect against incorrect power connection. - battery or accumulator with voltage from 1.5V to 9V. But it is better to give the maximum voltage, since with increasing voltage the radiation power of the device increases and, accordingly, the efficiency. The frequency of the generator depends on the capacitance C1 and C2, and the resistance R1. Several more piezo emitters can be connected to the contacts of the ZP-shki. It is advisable to choose models that are more powerful.
About the details for the ultrasonic repeller circuit. Instead of the KT361 transistor, you can use any other one pnp transistor similar in parameters (for example, a733, kt3107).
The ultrasonic repeller requires almost no adjustment, you just need to adjust the frequency of the generator using resistor R6 (you can use a frequency meter, to do this, connect the frequency meter in parallel with resistor R1).
The current consumption of the device is about 1.5 mA. Printed circuit board for ultrasonic mosquito repeller is shown in the figure below:
Archive with printed circuit board and the diagram in Lay format is on the forum. I wish you a great summer vacation, because now mosquitoes will fly around you for a kilometer! Material sent by R. Rybalko
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