Arduino controlled robot - finding air leaks

Other Hardware Sensors
1

Hello
I'm doing a school project where I'm supposed to make a robot which can find air leaks in tubes with compressed air. The leaks in the air tubes emit a frequency which you can find by using sound, I've tried using the KY-037 big sound sensors to detect a frequency but I cant really make it work, so I have to ask for some help.

specifications: I have an Arduino Mega to work with (I am able to get another microcontroller if needed) I have the sound sensors and other sensors from the Arduino sensor kit available and i can buy other sensors if these aren't good enough.
The robot needs to transport itself over to an air leak by detecting the air leaks frequency and guiding itself over there, then it needs to sound an alarm for a technician to fix the leak.
What do i need to do to get this going in the right direction?
If you need more information ask away, I need all the information i can get.

2

You found that the KY-037 detects sound LEVELS, not specific frequencies and it cannot be made to do that. What other sound detecting devices did you look at? You need one that allows you to filter out all frequencies but what you want.
The same scheme to find leaks is used in natural gas lines that are under ground. Perhaps some type of ultrasonic detector would work. Think of sensors for listening for bats flying around and echolocating.

3

An ultrasonic translator for detecting gas leaks can be made using this sensor:
Piezo Ultrasonic Receiver

4

And it also surprisingly directional, so should be able to pinpoint air leaks quite well!

5

Could probably get some clues from this old Nuts and Volts article.
Bat Detector