An animal that uses ultrasound is the bat, they use it to hunt at night. A lot of animals hunt in the dark, like cats and have special eyes to see in the dark. But because insects are too small to hunt even with that kind of eyes, the bat uses Ultrasound to locate insects to hunt on.

animal ecolocation
So he uses his ears to see (= echolocation). Not only bats use this method, also dolphins and whales. It’s even possible to do it as a human, Daniel Kish is blind from the age of 13 and has adapted to this, by learning himself echolocation.

human-echolocation-in-action

Not only nature uses echolocation, also submarines and cars use it, like you see on the first picture. Submarines can use sonar to check the depth of the sea or to see other objects in the neighborhood. Because we use ultrasound in our thesis I find it more appropriate to talk about the echolocation in cars.

example of park assist

Now a days every car has park assistance on it,  like you see on this picture there is already a lot of evolution in this sector.

evolution in ultrasound sensors

For the ones that don’t know how it works, the sensor transmits a burst and then he times how long it takes to receive the echo/reflection of the burst. Then he uses this time difference in combination with the velocity of sound to calculate the distance.

Because the sensors are used outdoor, they need to be waterproof. For this reason they opt for enclosed sensors, that can both transmit and receive. These types are normally less sensitive, but more robust.

An important factor, they need to choose in the application is at what frequency to transmit. Transmitting at a high frequency, makes your signal more directive, what is better to prevent interaction with the ground. For the same reason asymmetric types are used, sensors that have a bigger horizontal range than they have vertical.

directivity of higher frequencies

 

 

 

I hope you see that nature inspired this invention, you could see it as an example of biomimicry.

See you next time.

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