Ultrasonic sensor

Ultrasonic waves are one of the most widely used waves in sonar navigation using the Sonar method (Sonar: Sound Navigation And Ranging). In sonar-style navigation, a sound wave is sent from the transmitter. It takes time for this wave to hit an obstacle and return it to the receiver installed near the transmitter. Given this time as well as the speed of the sound wave, the distance between the transmitter and receiver to the obstacle can be calculated.

Ultrasonic waves

Ultrasonic (ultrasonic) waves are sound waves with frequencies above 20 kHz. These waves are not detectable by the human ear because the range of human hearing is from 20 Hz to 20 kHz. These waves can be detected by many animals. Bats, cats, dogs, and most insects and fish are in this category. Bats are among the animals that use the above technique for their flight (navigation).

Some of the features that have led to the use of ultrasonic sensors in many electronic applications are:

Inaudible to the human ear
High directivity
Low propagation speed compared to radio waves and light
They are produced due to the vibrations of matter
Ability to reflect transparent objects

The positive thing is that ultrasonic waves are not inaudible to the ear. For example, in car park sensors, to detect obstacles properly, a wave with a power of 100 dB is emitted by the sensor, which if this wave could be heard, would have the sound equivalent to hearing the sound of a jet engine up close.

The high directivity feature of ultrasonic sensors is used to treat and break kidney stones. The ultrasonic wave is focused and propagated from the outside of the body to the desired point. Due to the low energy level of this wave, the body is not harmed.

The low propagation speed of ultrasonic waves results in the use of low-speed processing tools to process related information. For example, an ultrasonic wave travels a distance of 10 cm in about 3 milliseconds, but an optical or radio wave travels this path in 3.3 nanoseconds.

Because ultrasound is due to the vibration of a substance, it is also used to determine the properties of a substance. Ultrasound uses the same feature to image the body.

These light waves, unlike light waves, are reflected after colliding with a transparent material such as glass. Therefore, the use of these waves in navigation also allows the detection of clear obstacles.

Ultrasonic sensor

Ultrasonic modules have an ultrasonic transmitter and a receiver. The waves are propagated through the transmitter and the reflected waves are received by the receiver. The intensity and quality of the reflected waves depends on parameters such as the material of the obstacle and its distance from the transmitter. Also, some of these waves, depending on the physical characteristics, pass through it.

The use of ultrasonic sensors in navigation received much attention after the Titanic accident. In the year of the accident (1912) sonar navigation is still in the experimental stages. Radar technology also emerged 20 years later. Today, the use of ultrasonic transmitters and receivers is one of the most common issues in the field of navigation, especially naval and submarine navigation. This technology is also used in ground and air robots to prevent collisions with obstacles. In many cars around the world, a number of these sensors are used to prevent collisions with obstacles and other cars.