TomK:
What i want to do is: when the button is released and the trail starts to fade as it travels down in its group, instead of just keeping the last values it received, I want it to keep displaying live values as the trail goes down. So lets say the light trail is two feet long going down the 20 foot strip, instead of a bunch of old values going from one to the next led, I want the trail to keep changing with live serial values but remain in its two foot section after the button is released.
I can't quite picture what you mean. I don't know what you mean by "its group" or a "section".