Problems with the KY-037 and KY-O38 noise sensors.

This is my first post in this forum, so in case I do something wrong, please tell me and I will try to correct it.
I am writing this post because recently I received for Christmas a pack of 37 sensors for Arduino. In this pack there was included this two noise sensors. I was very excited about them because I have never tried one of this before. So I connect the analogic port to the A0 of my arduino and wrote the test program which the kit tells you to test (you can see it in this web: and I always receive the same values: 19, 20, 21 and 22. It doesn't seem to react to anything. I have revised everything like 4 or 5 times and not the KY-037 or the 38 works, so I don't know if the sensor is broken or what

Thank you for your answer.

Welcome to the forum!

Can you post your code in tags? Might also want to post a pic of your project wiring (not a drawing).

Guess out of the blue: the grounds aren’t connected.

Thanks for your help but I think that I found the answer: the mic doesnt have an amplificator so the readings are very low. I read it in another post of this forum