Spy Cam Technology One Direction Developed to Produce Sound

The Acouspade Classic speaker radiates sound in one direction only – as opposed to conventional speakers of your voice from the recorded conversation.

Technology Direction

A machine that produces sound in only one direction has been developed by scientists. This piece of technology, which is known as an acoustic circulator, violates a fundamental principle, which states that sound and other forms of waves go in only one direction. The findings, which were published on the 30th of January 2022 in the journal Science, have the potential to lead to the development of a sound device that is analogous to a one-way mirror. People who have such a gadget can hear another person talking, but they themselves cannot be heard by the other person.

Nature Of The Wave

Time reversal symmetry is a physical property that is shared by all waves, regardless of whether the waves in question are audible, visual or radio waves. This indicates that a wave traveling in one direction can always be reversed and sent in the opposite direction. Andrea Alu, an electrical engineer at the University of Texas at Austin and one of the co-authors of the study, stated that “if I am able to talk to you, then you should be able to talk to me back.

“Researchers have discovered a way to circumvent this limitation while dealing with radio waves by making use of magnetic materials that spin electrons in a particular direction. Because the resulting radio waves identify the difference in the material when traveling in one direction as opposed to the other, they are able to prevent reverse transmission. As a consequence of this, transmission towers are now able to transmit the top 40 songs without the radio waves being forced to bounce back.

Sound In One Direction

But academics haven’t been able to figure out how to complete the trick for other kinds of waves up until this point. The team was able to achieve their goal by using sound waves, which are pressure oscillations in the air. In order to do so, they devised a cavity that was packed with miniature CPU (central processing unit) fans, which spin the air at a predetermined speed. When sound waves pass through the cavity, they are directed down one of three pipes (imagine the cavity to be the center of a sea star and each of the pipes to be one of the sea star’s appendages), and the end of each pipe is equipped with a microphone.

Because the air is spinning in one way, the wave “feels” different when it moves through the air in one direction as opposed to the other, which prevents transmission in the opposite direction. Because of this, sound waves can go in one direction, but they cannot travel in the opposite direction. The end effect is sound that only travels in one direction.

The listener at the end of the first pipe, for example, may transmit a sound signal to the listener at the end of the second pipe, but the first pipe will not be able to hear the sound transmitted by the second pipe. It’s possible that the second pipe can transmit a signal to the third pipe, but it won’t be able to receive one.

Applications Of One-Way Sound

The new method has the potential to be utilized in the production of a sound medium that is analogous to one-way glass. There are some obviously covert methods to utilize the method, such as in espionage devices like there are some obvious sneaky ways to use the method. According to what Alù shared in an interview, “I can listen to you, but you cannot detect me back, and you cannot hear my presence.”

However, the same technique might also be applied to the production of light waves that go in only one direction. According to Sebastien Guenneau, a researcher at the Institut Fresnel in France who specializes in metamaterials but was not involved in the work, the discoveries will most likely lead to a wide variety of practical applications. According to what Guenneau wrote in his research papers, “I would be astonished if sound businesses did not catch up on this notion.” It is possible that this discovery will find beneficial uses in the soundproofing of highways, recording studios, submarines, and airplanes.