Using USB to connect led units together and program

What I would like to do is used for pens to communicate up to 10 x 4 units

Project has to stay hush hush but let's just say it involves high power led being FET driven. Each led unit has 5 "modes" that must be able to be programed in real-time and remain individually programmable though daisychaining.

Ex. Unit one two and three are connected together and need to be able to go from all in setting one to only unit 2 in setting 2 while the others go between 1 and 3 .

I'm planning on using a broken down uno to control the outs but I don't know how to make it communicate in and out.

Also any ideas on how to switch 5 high amp low voltage inputs without using 5 different FETs ?

Don't cross-post. Your other thread deleted.

which other therad? i only cross pot for specfic needs such as display issues to display, progamming to programming, led mulitplesxing to led mulitplexing. etc. sorry if i messed up thought i was very tired! duly noted