In nature, male mosquitoes do not suck blood, and only female mosquitoes bite people and animals to suck blood when breeding. According to reports, users can download the "computer mosquito-repellent incense" anti-mosquito software for free as long as they register on empas website. After the computer is turned on, the software runs automatically without adding new accessories. Because people can't hear the frequency of the computer driven by anti-mosquito software, using this software has no effect on people.
A few days ago, SKT, a Korean mobile service provider, also launched an anti-mosquito ringtone service, which uses the same principle as "computer mosquito repellent incense". 〗
What we saw above is the mosquito repellent software released abroad, and the author also searched some domestic mosquito repellent software with similar "efficacy" on the Internet. According to the description of an electronic mosquito-repellent incense software, it can make sounds that imitate the natural enemies of mosquitoes-dragonflies and bats, creating a noisy environment that annoys mosquitoes and keeps them away. Moreover, this kind of sound is inaudible to people and has no influence on the human body. The slogan of some software is even more vowed: "Let mosquitoes give up and run away!"
Seeing this, it is estimated that everyone will have a question in their hearts. This is a lot of red mouth and white teeth. So, are these mosquito repellent softwares useful? Are they harmful to us? The author will discuss this topic with you below.
Principle of mosquito repellent software: ultrasonic wave?
Many net bugs who like surfing the Internet late at night have been bitten by mosquitoes, and everyone is looking for a good way to repel mosquitoes. There are many softwares on the Internet, such as mosquito repellent, electronic mosquito repellent KM300V2.0, Super Mosquito King, Yitian electronic mosquito-repellent incense and electronic mosquito-repellent incense.
In the download introduction of some mosquito repellent software, it is said like this:
"A new generation of intelligent broad-spectrum mosquito repellent software! The intelligent broad-spectrum mosquito repellent software developed according to the principle of bionics sends out the sound with the same frequency as the natural enemy dragonfly, bat or male mosquito through the computer to achieve the mosquito repellent effect. "
Some mosquito repellent software said: "This product emits high-frequency sound waves, not electromagnetic waves, so it is harmless to people's health. Please feel free to use it! "
Do you understand, no matter what kind of software, it is ultimately necessary to "strike" mosquitoes with sound through the computer, and the speaker is the terminal component to realize electronic mosquito repellent! So what is the "high frequency sound wave" mentioned above?
This so-called "high-frequency sound wave" is actually "ultrasonic wave". "Ultrasonic wave" means that when the frequency of sound exceeds the frequency limit of human hearing, people will not realize the existence of sound, so this high-frequency sound is called "ultrasonic wave". In fact, friends who like earphone products should know that the hearing limit of human ears is between 20 Hz and 20000Hz, which means that as long as the speaker can emit sound waves higher than 20000Hz, mosquitoes can be driven away.
This sounds feasible in principle, but can it be realized on the speaker? After careful thinking, the question is not difficult to figure out: can our common multimedia speakers play this "high-frequency sound wave"? This has to start with the manufacturing principle of the speaker.
The sound box is made according to the sound characteristics and the auditory characteristics of the human ear.
Sound has three basic characteristics, namely frequency, intensity and sound spectrum. These three characteristics are subjectively perceived by human ears as tone, intensity and timbre.
The number of times an object vibrates per second is called frequency. Generally speaking, the faster an object vibrates, the higher its frequency, and the higher the tone we feel. The slower an object vibrates, the lower its frequency, and the less tones we feel. But the human ear can't hear the vibration of all objects, and the vibration frequency of objects is too low or too high for the human ear to feel. Simply put, the speaker is designed based on this feature.
Common multimedia speakers are composed of sound generating units in various frequency bands. Due to the limited working range of different types of units, a set of speakers is equipped with at least three parts: bass, midrange and treble. After all, the high-pitched unit of the speaker is not a high-frequency sound wave generator, just as the low-frequency sound effect can't be perfectly expressed by the bass unit, the high-pitched unit can't emit too much ultrasonic waves, and when working in the ultrasonic section, although the upper limit of some high-pitched units can reach 30000Hz, the working state and efficiency of the speaker will be greatly reduced.
That is to say, there are few ordinary multimedia speakers that cannot be attenuated above 18000Hz, and almost none above 20000Hz, because the speakers are designed according to the hearing range of human ears, and it is basically impossible to emit sound waves beyond this frequency range from 20 Hz to 20000 Hz.
So we can easily draw the conclusion that the ultrasonic mosquito repellent is feasible in principle, but it can't generate ultrasonic waves with the help of audio equipment on PC, so it is unscientific to study such software carefully.
The above text is based on the analysis of our domestic mosquito repellent software, and the result is very clear. However, Korean software makes speakers emit sound waves of 200 to 600 Hz to drive away mosquitoes. Is this discovery really effective?
Can low-frequency sound really repel mosquitoes?
As we said just now, the hearing range of human ear is 20 Hz-20,000 Hz, and we should be able to hear the sound of 200-600Hz. For example, the vocal range is between 300- 500Hz. The sound of this frequency band, the speaker of the multimedia speaker with better quality can emit the sound of the corresponding frequency band. But will mosquitoes feel this sound? We still have a choice of sounds within human hearing range, so does this have a repellent effect on mosquitoes?
Through a friend who studies biology, the author consulted his professor at the Institute of Biological Diseases. The professor's answer can help us find the answer:
"Mosquitoes have a certain perception of ultrasonic waves, but due to the complexity of mosquito transmission, there are not many examples of sound waves acting on mosquitoes. When male mosquitoes courtship, they will send out a variety of signals of sound, smell or behavior to attract the opposite sex, and this communication mode varies greatly according to different mosquito species. I have also tested mosquito repellent tools that rely solely on sound signals before, but what really works is far from the obvious effect of chemicals. "
After reading the professor's explanation, I believe everyone understands that mosquito repellent software is technically feasible, but it is more difficult in practical application. In addition, our ears can hear the frequency band of 200-600 Hz. If the computer emits sound waves in this frequency band, it must be noise. Then who can put up with the noise and play games at the same time?
Medical experts can't give a final conclusion about the acoustic characteristics of mosquitoes, dragonflies and even bats, so it is not reliable to judge the application of so-called bionic simulated ultrasound in real life on which mosquito repellent software is compiled. However, without professional testing, it cannot be completely denied.
It is not reliable to use mosquito repellent software to repel mosquitoes with speakers. Here, I still suggest that you use traditional pesticides and mosquito-repellent incense and take a bath frequently. The experiment found that the degree of mosquito bites was different before and after bathing. Therefore, some experts suggest that frequent bathing or eating garlic, onions and other foods can repel mosquitoes. The unpleasant smells of plant mosquito are orange peel, mint, fennel, clove, lavender, eucalyptus, citronella, platycodon grandiflorum, geranium, basil and thyme. If dried orange peel and orange peel are wrapped in stockings and put in the corner, the smell will not only prevent mosquitoes but also refresh the air; When taking a bath, drop a few drops of toilet water or essential oil in the bathtub, which will not only feel refreshing, but also repel mosquitoes, but be careful not to use it excessively to avoid irritating the skin; Drop geranium essential oil (4 drops) into almond oil (10 ml), mix well, and apply it on hands and feet, or less on face, to prevent mosquito bites when going out or sleeping; Buy an aromatherapy stove, drop a few drops of lavender or eucalyptus essential oil, and the room will suddenly be fresh, and the "buzzing" sound will suddenly disappear. However, the fragrance lasts only 1-3 hours, so we should grasp the time. Before dusk, put 1 2 pots of blooming jasmine, Milan or roses indoors, preferably cordate telosma. It can also play a very good mosquito repellent effect.