@barnun posted:
...Stan, the optoisolator place holder in the schematic is a prefab 2 channel board of which I have 4 or 5 on hand. When designing my board I simply placed two 4-Pin female headers the proper distance apart so the prefab (male pins) drop in for easy replacement. Looks like the chip on the board is D216. Yes, my intent is to provide a 5v signal level output to an Arduino Mega 2560 Pro Mini.
...bricks, tied to a single ZW-C and properly phased.
... These LTV-8x4 chips seem to be spot on for this application. Any thoughts on the current limiting resistors?
Regarding the current limiting resistors, I was just going to comment that you choose them the same way you did for your existing optoisolators. But if I understand it, your existing optoisolators are purchased modules that you did NOT "design" it yourself?
That said, just do a search for optoisolator or optocoupler design. It's not just the input resistor(s) to play well with the 18V AC track voltage but also the output resistor (and smoothing capacitor if needed) to play well with the 5V Arduino connection.
I could just give you some ballpark values that would probably work with a typical AC optoisolator but better to confirm which exact optoisolator chip you plan to use. Also, if you want to only use components you already have like the existing resistor and 330uF capacitor then this would be more challenging.
