Now for those that don't have a notification light, there's an app called NoLed and you guys should give it a try. For what it's worth, free, it's really good. I think that sometimes it's even better than the light, so go ahead to the play store and check it out and let me know if it worked for you.
https://play.google.com/store/apps/details?id=com.led.notify
https://play.google.com/store/apps/details?id=com.led.notify