The electronic circuit presented below will help you get rid of moles and other underground pests in your summer cottage. Basic electrical diagram.
Typically, in such circuits, EMX-309L1 emitters and the like are used as a vibration source. If such an emitter is not available, you can use a small-sized relay for the appropriate voltage. When appropriate pulses are applied to the relay, the relay contacts continuously switch, thereby causing vibration in the relay body. The relay body is rigidly connected to the device body, through which vibration is transmitted to the ground. It should be noted that underground inhabitants are very sensitive to various kinds of sounds and vibrations underground. Moles are able to sense a crawling worm several meters away and hunt for it. Various types of vibrations and extraneous sounds have a depressing effect on moles and force them to leave unfavorable habitats. The mole repeller circuit consists of two generators on microcircuits IS1 and IS2. 
Bread board.
The generator on the IS1 chip sets the operating intervals and pauses of the repeller. Using resistors R1 and R2, you can measure the operating intervals of the mole repeller. Typically 5 seconds on and 60 seconds off. A second generator is assembled on the IS2 chip, which controls the relay through the key transistor T1. The frequency of this generator is selected within the range of 200-400Hz. The frequency of this generator is adjusted by resistor R3.
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 in various 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 spreader with its teeth, lowering it back into place after the other rat pulled out the bait. Rats are so capable of adapting to different 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 convinced 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.
Different sources provide different versions of ultrasonic frequencies that repel 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 circuit of an 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. The schematic diagram of the ultrasonic rodent repeller I developed and implemented 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 these, the ultrasonic generator operates for 45 seconds, 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. You can see the appearance of a working generator in the photo above. All elements of the device are fixed inside the case using a 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 the nervous system of 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 effects on myself. 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.
Moles in a summer cottage or garden are the main danger to the future harvest. Previously, chemical or mechanical methods were used to combat these rodent pests, which allowed them to be killed.
Today, there are more humane ways to combat these pests - special electronic devices that scare animals away from the area using sound.
A large number of such devices are offered on the consumer market, but they are often quite expensive and not everyone can afford them. But anyone who has at least a little knowledge of electronics can make a mole repeller with their own hands on a microcircuit.
A do-it-yourself mole repellent device is a simple device in terms of design, the basis of which is the circuit of an ultrasonic mole repeller.
An ordinary metal can left over from coffee or pet food can be used as a housing for the repeller.
To ensure the protection of electronic components, it must be hermetically sealed with a lid. The electronic circuit of the device will ensure the formation of sound impulses that are intolerable to moles - this will force them to hastily leave the occupied territories.
Repeller design
To create the simplest electronic mole repeller with your own hands, the electronic circuit must include two logical chips, a transistor and passive resistors, which are placed on a printed circuit board. To power such a circuit, 3 batteries or AA batteries will be enough. Various schemes of simple mole repellers can be found on the Internet.
For those who don’t want to look for something and come up with something on their own, you can make a mole repeller with your own hands using the NE555. NE555 is a ready-made integrated circuit, a kind of timer that allows you to generate repeating sound pulses with stable timing characteristics.
The role of the sound wave emitter, which is generated in the mole repeller by the ne555 circuit, can be performed by a regular TK-67-NT telephone capsule. It can be taken from the handset of an old telephone. Capsules of this type emit sound waves well in the frequency range 0.3...3.4 kHz, which is excellent for repelling earth-moving pests.
Setting up and using the repeller
After the electronic circuit of the device is prepared, the telephone capsule and batteries are connected to it, they should be installed in a jar and closed with a sealed lid.
To prevent shorting of the contact tracks of the printed circuit board and damage to the batteries, before installing everything in the jar, they can be placed in a plastic bag.
To adjust the duration of the pulses and their frequency, you should use the adjusting resistors of the electronic circuit.
The finished electronic repeller should be buried in the ground near the place where the moles appear, and it will begin to work. The capacity of three batteries will be enough for the device to work for a whole season, effectively protecting the area from pests.
Video: Do-it-yourself mole repeller from a tin can
The off-season is a good time to prepare for next year, when you can make a mouse repeller. This device allows you to protect beds, storage areas and housing from rodents, moles and shrews. Ultrasonic repellers with a complex circuit and at a fairly high price are sold in stores. However, you can make such a device yourself on a budget.
Rodent and mole repellers operate using ultrasound. Signals at high frequencies (30-70 kHz) are not perceived by humans, but are clearly audible to pests. It irritates their nervous system, and animals tend to leave the discomfort zone. Factory-made repellers can also generate electromagnetic waves, which further suppress rodents. Devices can be powered by batteries (rechargeable batteries) or mains power. Electromagnetic pulses, unlike ultrasound, are able to penetrate almost any surface except metal.
To make a mouse repeller, you will need basic knowledge of electrical engineering and the ability to use a soldering iron. There are many examples of working diagrams with photos. Simple and universal repellers have the following advantages:
- high efficiency;
- reducing the risk of errors during manufacturing;
High-quality repellers effectively eliminate rodents - no need for adjustment devices during design;
- economical in terms of energy consumption;
- unpretentiousness to working conditions.
Preparing materials for installing the repeller
For a simple DIY version of a battery-powered repeller, you will need a set of radio parts:
- Piezo emitter (BQ1 in the diagram). The key element of the radio circuit reproduces ultrasonic waves. Any model will do. For example, from the ZP series.
- Resistors (R1-R5). They set operating points for transistors and perform a lot of auxiliary functions. For a repeller, 5 pieces will be enough. conventional output elements with a power of 0.25 W.
- Variable resistor (R6). Regulates the frequency of outgoing ultrasound waves. Selected in accordance with the rated power of the piezo emitter.
- Capacitors (C1-C2). Involved in the formation of frequency contours. For the repeller, use ordinary ceramic outlet elements.
- A pair of transistors (VT1-VT2). They enhance electrical vibrations and form a frequency circuit with other parts. Use PNP transistors: KT361B, 2T3307V, 2T3307A, KT3107 and others similar.
- Diode (VD1). An auxiliary part in case of an accidental polarity change when connecting. For example, KD503A.
- Slide switch-toggle switch for turning the power on and off.
Repeller device This mouse repeller is powered by batteries or batteries of any type. Power is in the range of 1.5-12 V. The higher it is, the stronger the ultrasonic vibrations of the device will be. If you plan to power the battery from a Krona type battery, provide additional special pads for them.
To protect against moles and rodents, you can attach a regular capsule from the receiver of an old landline telephone. Part brand TK-67-NT, TON-2, TA-56, TA-56M or TG-7. The winding resistance should be approximately 60 ohms. Such elements generate waves at a frequency of 300-3400 Hz. The resistance of the microcircuit inside the part is 260±52 Ohms (at a power level of 1000 Hz).
Attention! The main advantage of such a repeller is the tightness of the emitter housing.
Making a mouse repeller body
It is convenient to make the device based on a cylindrical metal can of coffee, animal food, etc. Repeller assembly procedure:
Advice. It is best to place the printed circuit board in a plastic bag. At the point where the wires exit, tie it with thread.
Instead of a telephone capsule, you can use a purchased piezo emitter. The principle of assembling the repeller in this case will remain unchanged. Only the ultrasonic wave generator will require additional insulation. The can will add additional distortion to the radiation, so the sound of the repeller will seem even more disgusting to rodents and moles. In fact, the metal itself will vibrate, receiving an impulse from the emitter.
Close the jar with a lid. Then bury it in the chosen location. The depth is approximately half the height so that water does not get under the repeller cover. It is far from ideal in terms of tightness.
Be prepared that you won’t be able to eliminate the pests right away. Time must pass - up to 2 months. If you plan to place the repeller indoors, make it more powerful. Walls and other obstacles will reduce effectiveness when the sound is low.
Other pets may also react negatively to the waves. In this case, adjust the frequency. Experiment with this at the stage of assembling the repeller circuit.
Mouse repellent device: video
And the influx of pests is such that traps can’t cope; it’s worth purchasing an ultrasound generator. There are enough foreign and domestic models in stores. But you can make an ultrasonic rat and mouse repeller with your own hands.
What parts to use
The device can be assembled using a ne555 or ne556n timer. Microchips P416 and KT315 will make the signal, which is responsible for repelling rodents and insects from the house, stronger.
Before you begin assembly, you need to acquire the necessary parts:
- capacitors C1, C2, C3 - one piece each;
- resistors R1 and R2 – 2 pcs.;
- resistors R3, R4, R5 – 1 pc.;
- transistors KT361, GT404, GT402 – 1 pc.;
- 5 V battery – 1 pc.;
- dynamic head – 1 pc.
Parts can be removed from unnecessary or old electronic boards or you can look for components of the microcircuit on the market.
On a note!
The speaker should be selected based on the area of the room. A power of 0.5 W will allow ultrasound to spread over a distance of a thousand meters.
Variable resistors (R1 and R2) help set the output level of ultrasonic waves. Simple resistors (R3, R4, R5) reduce the voltage in the electrical networks.
Capacitors and transistors allow you to make a frequency circuit.
You will also need the following components:
- diode - will protect the device if it is incorrectly connected to the network;
- piezo emitter – produces an ultrasonic signal;
- toggle switch – turns the device on and off.
You will need to buy a soldering iron. Without it, the rat and mouse repeller circuit will remain unassembled.
How to assemble
Before assembling the parts, you need to check the drawing and put the wiring in order. Their ends need to be cleaned and treated with rosin and tin.
The ultrasonic rodent repeller circuit is assembled on a textolite. But if it is not there, then you can simply solder everything together with wiring. Two long wires are separately connected to the power supply and to the speaker.
All parts of the ultrasonic repeller are soldered gradually. There is no need to rush in this matter, because the transistors can overheat and the rat and mouse repeller will not be able to work.
After assembly, a power source is connected to the device and the device is tested. The speaker should make a slight squeak.
The ultrasonic rat and mouse repeller is placed in a housing. For this purpose, take a suitable box. Even a cardboard candy box or a cigarette pack will do.
Use a needle to make several holes in the box on the speaker side. A homemade device will make sounds unpleasant for mice and rats
How the device works
Produces high-frequency sounds within the range of 30 – 70 kHz. The human ear does not perceive this frequency, and many cockroaches and other pests begin to feel discomfort.
Some devices emit electromagnetic waves in addition to ultrasound. The latter even penetrate walls and allow you to scare away living creatures at a greater distance. Ultrasound waves, meeting an obstacle - a wall or furniture - are reflected from it.
On a note!
The frequency of repelling mice should change from time to time. In this case, rodents will not be able to adapt to the device.
When creating or purchasing a device, you should consider where it will work.
