Can I use Aux + Blue switches for separate loads on the same breaker?

I’m a little unclear on how the Aux switches actually communicate with the other smart switches and what exactly they can do. I see that they must be used with another smart switch on the same circuit but I’m not certain if what I want to do is possible or not:

I currently have a Blue 2-1 controlling some non-smart bulbs (“room 1”). This circuit is on the same breaker as the lights for another room nearby (“room 2”) where I have some smart Hue bulbs that I would like to control via a smart switch in that room. I don’t need the full switching/dimming functionality and LED bar of another Blue switch in room 2, so I was wondering if I could use an Aux switch to control the smart bulbs by having it tell the Blue in room 1 to trigger some command? It’s not clear to me what functionality the Aux switches can actually perform.

If this isn’t possible, what other solutions would you recommend? (My current solution is to keep the dumb switch in room 2 always on and use a separate button (config or double-click) on room 1’s Blue switch to control the smart bulbs in room 2 :laughing:)

The Aux switch needs to be hard wired to the blue switch. A physical wire is connected using the traveller port. If you want a “wireless” 3way setup, then a second blue switch must be used and connected either through binding or through automation.

Since you’re using hue bulbs in room 2, if you are able to make that physical connection between the blue switch in room 1 and the aux switch in room 2, then you could use automations to control those hue bulbs through something like a double tap. I can’t see these switches being wired this way though, and the cost and effort of re-wiring is probably going to be more than just putting in a second blue switch.

The Aux switch has no switching capability itself. In fact, it has no smarts of any kind. It’s simply a few resistors of different values representing the different buttons. The main “smart” switch detects the different resistances (related to each button) and acts on that.

The aux switch must wire to one of the full smart switches, so Red or Blue.

The new smart switches support having specific scenes for the aux switch. So, you can get tap and hold scenes from the aux switch in your hub and use those to control anything you want. BUT. the aux will also still control the blue switch, you can’t disable that and I don’t believe the blue would recognize the aux switch scenes unless its set to 3-way aux switch mode…

The other problem I expect you’ll have is that there must be 2 wires running from the aux switch to the blue switch. One is the neutral shared with anything else in the circuit. The other is a dedicated wire. You probably don’t have these 2 wires available from the room 2 switch box going back to the room 1 blue switch.

In any case, its an interesting idea to use an aux as a scene controller only. There’d have to be a firmware change to do this though.