A free program for Android, by devsoftapp.
In this app, you can customize the flash alert for each contact, so you won't miss any important calls and messages from your favorite contacts. This app allows you to turn the flash alert on or off, which you can quickly toggle with a single button.
How to Use?
This app uses your camera to blink the flash, so you can quickly answer any calls or send any messages you get.
To Turn ON or OFF the flash alert for each contact, just tap the button at the bottom of the screen. The contacts will be listed in order, starting with the person who sent the most recent message.
