Well, I've completed my set of eight switches, my machine has two drives in X so i wanted a set of home+limits on both sides of the gantry. Each home/limit pair is joined in series. I designed them to run at 12V rather than 5 to address any potential noise issues and also its easy to tap off 12v from the controllers PSU. I used optocouplers to adapt that voltage to the bob.
I also made them N/C in order to address the inherit safety problem with using an N/O switch, I.E. if a sensor fails or a lead is damaged the opto (which is at the bob end, not the sensor end of the cable run) will go open circuit and trigger a stop. This meant making a little optocoupler bob adapter. The switches themselves have two leds in them, a uv one to show the switch is running/powered at a glance which changes to a red one on trigger. I'm pleased with the results, they do everything I wanted in a tidy self contained way. Here are my circuits and a little story in pictures.
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