One logical output(digital pin) to drive 8 relay board with a small delay

PaulRB:
Could you re-word that so it's a bit less self-contradictory?

I can't see your diagram. The forum guidelines so tell you how to attach a picture to your post.

Well, you are right, it is simultaneously - logic wise, because is one event that trigger consequential relay closing

Delta_G:
Looks like a shift register to me. I'm not sure how you think it could get any simpler unless you want to pull all 8 lines from the Arduino itself.

That was what I thought, thank you