Web alarm clock for 11:09 p.m.
As you finish the ninth evening of family prayer and leave the room, set the alarm for 11:09 pm so the moment does not slip past while you put things away. It gives you a clear cue before 12:00 am, when the household may already be settling down. You can move on without repeatedly checking the clock.
Because you are leaving after family prayer, keep the browser open until the alarm sounds. Closing its tab or quitting the browser cancels the alarm, so it will not remind you about prayer later. Also make sure the phone or computer stays awake and has enough volume for you to hear the signal from the next room. A quick glance at the displayed alarm time before you walk away can catch an accidental am or pm selection.
When prayer ends late in the evening, a loud signal can carry through a Filipino home where relatives may share nearby rooms. Place the phone close enough for you to hear 11:09 pm, then choose a moderate volume that will not startle anyone preparing for sleep. If someone else is still cleaning up, let them know what the sound means so they need not wonder whether something requires attention.