Since the LG Optimus Android devices don’t come with external notification lights for missed calls, XDA forum member mmarz decided to perform not only a software mod, but also a hardware mod to bring the missing functionality to his mobile phone.
The mod turns the backlight of the hard keys into a notification light, and the backlight LED into an external LED. Note that the hardware mod is not necessary but does complete the look and functionality of the mod.
The software mod can be done using a choice of two methods. Method one involves no flashing lights and is the most efficient and least taxing on the battery. Leaving the lights on permanently requires a modified kernel. Method two involves a script by the XDA member and turns the lights on and off, combining this with Tasker will give you a dedicated notification light but consumes more power than method one.
The hardware mod requires some opening up the phone and applying a drill to your device, and of course will void your warranty.
For a comprehensive write up of both the software and hardware mods, head on over to the modification thread._________