What I’m looking for is:
When some lights are switched on via a clock, let’s say “contact A”, I want to switch another contact(normal open) " contact B " almost at the same time. Due to the distance is approx. 500 meter, I was wondering if something is possible via SMS?
In this case, contact “A” when it’s closed, create an sms and send this to “something” who can receive this sms and activate contact “B”
Just to be clear, not via a smart phone or an app that you must activate first!
Thanks and kind regards,