Ok what 3.5mm sockets did you design for?
It also appears that on the board the connection from the optoisolator connects to pin 5 (3 in my case) not pin 2. This means the connection is at the ring terminal (mid) not the top. When you look at the datasheet there is a view labeled “PCB Layout” which shows the view looking down onto the top of the PCB through the component. A simple change in the wiring will fix that so I’m not overly concerned.
I am very happy with this design (great use of ground and power planes plus the breadboard area!). I just soldered all the components on last night. I’m using a buck converter instead of the LM7805. I just uploaded the Arduino sketch so I haven’t had a chance to test it out yet. I’ll post again when I do.