Hi, new here, not an expert at all, would like to know if it's possible to create something that starts playing a prerecorded audio message when a noise is detected, basically, you record an audio, and this audio starts playing every time a noise is detected. Hope you can help, thanks.
Sure, that is possible. Any Arduino can be equipped with a microphone and listen for "noise".
There are modules on the hobby market that will play tunes or recorded messages from an SD card, under program control.
Search phrase "sound playback module with arduino"
The examples given detect a sound level, not a specific type of sound. You need to put some thought into what you really are describing as a "noise".
Thanks for the answers, not a specific noise, could be a clap or a generic voice command to start playing the prerecorded audio, my idea was something like Isd1820 with a recorded message activated by a Ky037 and amplified by a LM386.
Those are two very different things. A noise like a clap would be far easier to detect than to recognize a specific command.
Perhaps bernuga could write a few words explaining the difference between a noise and a sound of voice.
Hi, sorry, didn't use the right words, I'm talking about every kind of noise that, for example, above 30Db will make the sensor recognize it and prerecorded audio starts playing, until next noise is detected.
I can clap, I can scream, everything above 30Db (as example) will be detected and do the job.
Noise above 30Db > noise sensor gives signal > prerecorded audio starts playing 10 seconds > stop
Thanks
Start with the devices that Larry suggested, The mike board has an adjustment to set the sound level that the device sends a signal.
Ok, I'll check on it, but I would like something like a closed system, you can register your message on it, the sensor will send start signal, the speaker is part of the system, that's why I was wondering if a sound sensor like Ky037 could activate somehow a LM1820 board, because this would be everything I need all together.
dB (decidel) is a relative measure and for DIY equipment, requires calibration against a standard.
For a simple level-triggered action, you can set an arbitrary, but adjustable voltage level in your program code.
Hi, but I think DFP needs a sim or mp3 card, so you would need to record your message on another device.
LM1820 would really be great for what I'm looking for, noise sensor should only activate the prerecorded registration like you do when you push the LM1820 first button.
I can find a lot of motion sensor that can start a prerecorded audio, but none that do the same with noise instead of motion, if there are noise sensor that can turn on a lightbulb, I think they could give the signal and turn on a prerecorded voice, or not?
The suggestions within will work.
Seems like you have come here with your mind made up already.
I'm here to listen and learn but of course I have an idea of what I would like to build, the DFP player needs a sim card so you need to register your message on another device, the LM1820 is like a closed system where you can record and listen through a speaker.
The DF Player Pro can store audio on its internal flash and does not require an additional SD card.
Hi, thanks, this is interesting, how do you record your message on the internal flash?
As an example on what I'm talking about, image a small box, 2 buttons, 1 on/off, 1 to record your message, an internal small speaker and a noise sensor.
You put this box somewhere in a library, when tot Db noise over a prerecorded limit is detected, a gently message starts "please shut the f... up" or any message you want to make people stop talking.
Just be sure to disable the noise sensor until after the audio has been played. 
Could someone post a link to the LM1820 we're talking about? I can't find anything that looks relevant.
Good point, it would be a loop.