A Hidden LED under the Earpiece in Moto X
There is a hidden LED under the earpiece in the Moto X, Google's smartphone. But you need to root the phone in order to use it. For rooting process, you can read the post "how to root Moto X".
The Moto X has an excellent and incredible innovative feature called Active Display, which shows notifications using the AMOLED display in the center of the screen. This awesome feature is excellent than any notification LED.
I recently found an LED hidden on the Moto X. It was under the earpiece this whole time.
This LED is used to signify that the battery is so dead, that there isn't enough energy to even turn on the screen and show the dead battery icon. Getting your phone that drained is unlikely, so most of us may never see this warning.
However, the brilliant people at XDA have found out how to use this LED. Unfortunately, this procedure does require both root and Tasker, so unrooted folks won’t be able to get that LED lit for their own purposes. But if you're rooted and want to mess around with Tasker for a while, this is an awesome project.