i've found these Toturials for an Alarmmanager: http://michael.theirwinfamily.net/articles/android/android-creating-alarm-alarmmanager
It's one that is not using Broadcast.
But it is not saying what I should put into my Manifest-File thus an Activity starts.
I've tried the following, but none of these work:
<receiver android:name="alarm.starter.AlarmReceiverActivity"></receiver>
<receiver android:name=".AlarmReceiverActivity"></receiver>
<receiver android:name="AlarmReceiverActivity"></receiver>
Please Help