A free program for Android, by Pinnacle Labs.

LED Notifications is a simple and convenient application for you to get notified of incoming calls, messages, and other notifications on your Android phone or tablet. This application will notify you with an LED light indicator on your Android device, which you can customize with different colors and styles. You can also set it to flash or blink, and you can customize the frequency and duration of the notifications. It is easy to use, so you don’t have to worry about it. It is compatible with most devices that use the Android operating system.