Step 1
I built the Serial, for a reason of timing i had to mill the boards before to redraw them
The boards on the pictures are not the boards in the final tests below
Bridge

Node

I built the Serial, for a reason of timing i had to mill the boards before to redraw them
The boards on the pictures are not the boards in the final tests below
Bridge

Node

I milled and stuffed the boards

Then i programmed them with IDE arduino

Don't forget to look after ATtiny librairies, watch your settings in the tools of the IDE
Copy the C code on the nodes, make sure you have given a different number to every one of them (#define line_id'nb')

Test
