ST Control with No Switch?


I’ve done a bit of searching and could never find me exact scenario, apologies if this has been addressed already.

Previously, I had a ceiling fan with a light in my living room. The fan and light were both controlled via a pull string, and there are no wall-mounted switches to control it at all. I eventually removed the ceiling fan, since it would have been in the way of a ceiling mounted projector I was installing. I replaced the fan with a low-profile LED light fixture. Since there was no switch to control the circuit, I installed a wireless ceiling fan control module between the wires and the fixture, allowing us to turn it on and off with the tiny enclosed remote control.

Now, we’d like to incorporate it into our SmartThings routines, but I’m unsure how to go about it. I’d considered purchasing a ST compatible light switch that you’d ordinarily install in the wall and simply mount it inside the fixture or over it (in the recess the ceiling fan was mounted to), but I’m not certain that it will fit in either dimentionally, and seems somewhat dangerous. I’m aware there are inline modules that I could use, but it seems that most of those are also intended to connect to a wall-mounted switch. The wiring I have at the fixture is only the 2 wires and a ground. I’m unsure about a “neutral wire” I’ve seen mentioned elsewhere. I’ve also read that the inline modules aren’t suitable for LED lighting and only incandescent.

If anyone has some insight or can provide guidance on my options, I’d certainly be grateful.

( co-founder Terry @ActionTiles; GitHub: @cosmicpuppy) #2

2 wires + Ground at a power sink (ie, at the light/fan rather than not at a switch where the situation is different…) means one of those wires is hot (incoming power from the electrical grid) and the other neutral (returning to the grid).

BTW: At a Switch with no neutral, one wire is hot (incoming from the electrical grid) and the other is also hot (continuing to the lightbulb before headed back to the grid). Certain Switches that don’t need a Neutral are able to steal some power on the way; used to do this by trickling current through to the bulb at such a low amount that the bulb didn’t light up; but that doesn’t work with LEDs or CFLs… So I don’t know how the Lutron Casetas do it!.

Anyhow, I think the right solution for your situation, if you are willing to lose control when SmartThings is down, is to install a micro-relay (usually Z-Wave) inside the fixture.

I use Monoprice and works fine (though frankly I’ve had my first two fail under warranty).

Those, indeed, have a convenient feature that you can loop a Switch into them, but they work just fine without a Switch. They appear as a Switched Outlet to SmartThings.


Thanks for the insight. That sounds like exactly what I need. I’ll look into it.

(Robin) #4

Do you have other light switches in the same room?

If so, are they integrated with ST and how?

Reason I ask is that you could use a Zwave plus micro (capable of association) behind the light fitting (where fan used to be) and then a matching micro module for the other switches circuit, and link them together using direct association (will work when hub is offline and gives you a switch at the wall without having to chase wires).

I would reccomend the Fibaro Dimmer 2 modules as they allow for two switches. You could therefore convert a single wall switch into a double switch, one switch to control the original light and the other to virtually control the ‘fan’ light.


There are other switches in the room. In fact one doesn’t appear to run to anything now. It’s an old house with frankly mystifying wiring decisions. You propose and interesting solution. I’ll take it under advisement. Thanks.