I'm working on building an Ardunio Nano device that detects if automotive 12V circuits are on / off. I was able to successfully build & test a sample circuit provided Phil Frost.
The question I have is around saving space. I'm using this in a motorcycle so space is at a premium. The 4N25 uses 6-pins, even though I only use 4. I'm monitoring 6 separate 12V circuits and I'm wondering how to make it more compact.
Is there another chip (maybe a multi-optocoupler) or approach that will help me save PCB real estate?