EDIT: Oops, I meant to say hot/neutral for (+)/(-). I'm not completely educated in this as you can tell. ^_^;;
I live in the U.S. I'm attempting to figure out if it's possible to hook up a Sonoff Wi-Fi switch to my house's light fixture, let alone if it's possible to do it with the existing wall switch. I know there's Wi-Fi switches you can buy that only require you replace the existing light switch, but they're super expensive, and the Sonoff is only $4. So I want to get this to work so I can use my phone to turn the light on or off no matter where I am in the world. I also want to still use the existing wall switch to control the light. But I'm not sure it's possible since Sonoff outputs two wires whereas a regular light switch just cuts off the (+) wire to control the light.
Here is the current wiring setup of one of my ceiling lights and its wall switch:
The AC's (-) connects directly to the light's (-). Then the AC's (+) goes down to the wall switch (a switch leg wire, I'm told it's called), then back up again to the ceiling and into the light's (+). This way the switch turns on or off the (+) to activate the light.
My plan, if it will work, is to mount the Sonoff box above the light's junction box in the attic. Power the Sonoff with the AC's (+)/(-) from the light box, then feed Sonoff's outputted (+)/(-) back to the light. Simultaneously, have the AC's (-) connected to the light like now, then still have it's (+) going to the wall switch and back to the light to turn the light on or off like now.
Would this wiring setup work to control the light with both Sonoff and the wall switch? If my diagram is correct, do I need the extra neutral wire going into the light, or is the one going through Sonoff enough?