[jJuniorHRW]

Woodcote,
I appreciate the information you provided in your initial post.  Being an electronics neophyte, I still have some questions.   You mention a dead strip diagram that you used, is it posted or am I miss reading your comment.  From what I understand from what you built, you added a single channel opto-isolated relay board for each dead strip.  I did find this diragam which has some issues, but helps as a starting point.  Reading your post, I would need to add the optocoupler to the dead strip connections to limit any potential damage to the Arduino board.   Do you have a diagram on how you wired those.
Thanks