Well, if the faithful believers desire to wake up from their sleep at a particular hour they also should seek it. If one wants to wake up after pre-dawn meal during Ramadhan or for any other good deed he should recite the last verse of Surah Kahf and then go to sleep.
قُلْ إِنَّمَا أَنَا بَشَرٌ مِثْلُكُمْ يُوحَى إِلَيَّ أَنَّمَا إِلَهُكُمْ إِلَهٌ وَاحِدٌ فَمَنْ كَانَ يَرْجُو لِقَاءَ رَبِّهِ فَلْيَعْمَلْ عَمَلاً صَالِحًا وَلا يُشْرِكْ بِعِبَادَةِ رَبِّهِ أَحَداً
This verse is indeed a miracle. A number of great men have experienced its miraculous properties. It is written that if one says that once I tried but could not wake up at the desired time, he makes a mistake. Do trust that he did wake up at that moment but as he was sluggish he slipped in sleep again.
(This really works, try it)