Automatic task when mobile on, like a daemon

Hello every one

I would like to create an app. The purpose of this app is to launch in background some function.
For example send SMS at a specific date

For this i need to do a kind of deamon to wait the good date or for other function the good event

I can’t find any plugin or method to creat something like a daemon

Also i use the backgound plugin but it’s not exacly what i want, because the app it’s still visible by the user, i want something like the alarm whitch is completely invisible.

Hope you can help
(sorry for the english i am french)