I have been reading many such articles and have found no way to simply detect flow through a mains wire at low current.
At .27A for one LightBulb, I was calculating .05mA out of commercial 1:2000 inductance sensors, and no IC Hall Effect sensors are rated for less than 1A.
I only want On/Off Resolution to feed into a transistor and trigger a relay, so I consider my options to be:
Use a drill to wind a ~4000turn coil with very thin resin coated copper, wrap it around the wire and pray for o.1mA that I can amplify (Darlingtons? Is this possible? Is it stable?)
A Hall Transistor, also with lots and lots of gain?
With Capacitance Coupling "make the probe itself as a small coil and amplify the voltage dropped (not induced)" These will share a common Ground. (Is there some freaky way to make a magic resonant coil around the wire... yes i'm looking at you Tesla.) This seems like I am LOSING power to the mains, but at least I can sense it.
Anyway, if I get this working I will share share share cos there are a lot of frustrated forum posts around but no damn answers.
Please comment / recommend / crush my delusions of grandeur so I don't have to waste all my time failing around.