I am planning on making a button that is when pressed sets an alarm on my phone. I am planning on making an app that is creating the actual alarm, the app just have to be triggered by the hardware button.
My questions are:
Is this possible without a server (or is there a way to send directly to the phone, bluetooth maybe?)?
Can the app be triggered even if it is not running? (The app should just be installed on phone but you don't have to open it in order for it to receive the signal)