[pozitiffcat]

public class WakeLocker {
	private PowerManager pm;
	private WakeLock wake_lock;
	private boolean locked = false;
	Context _context;
	
	WakeLocker(Context context)
	{
		_context = context;
		pm = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
        wake_lock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, "MT");
	}
	
	void lock()
	{
		if(!isEnabled()) return;
		if(!locked) wake_lock.acquire();
		locked = true;
	}
	
	void unlock()
	{
		if(locked) wake_lock.release();
		locked = false;
	}
}

плюс в androidmanifest

<uses-permission android:name="android.permission.WAKE_LOCK" />