This app was mentioned in 2 comments, with an average of 1.50 upvotes
There's apps that are pretty easy to use. Sends an sms or calls another phone when it detects noise. like this one
This app seems full of features and looks great. But I see no need to switch from the Baby monitor I've used for years: https://play.google.com/store/apps/details?id=dk.mvainformatics.android.babymonitor