HI All As part of my glass fusing kiln project, I've a need for my Raspberry Pi to 'know' when one of the big, 240v-operated contactors has pulled in.
(It's a 'safety' sp/no contactor, with the ability to drop mains power from the 7.5kw heating elements in the event of a fault condition being detected. The safety contactor is in series with the main switching contactor - which, because it's switched quite frequently, is probably more likely to fail on 'in service').
In the interests of safety, it'd be helpful if the monitoring RPi was able, at the start of a fusing session, to pulse the safety contactor on/off - just so's it knows that, if it wants to, it _can_ drop the contactor out.
So - what's the easiest / simplest / cheapest way to turn the 240v on the switched contacts of the contactor into somethaing that the RPi likes - either clean-contacts or a 5v logic signal?
Thanks Adrian