Zwave Switch Conditional?

I can’t find this anywhere after months of searching. Here’s what I hope to do:

  • I have two zwave in wall switches. Let’s call them “A” and “B”.

  • Both are being managed by smartthings hub

  • I want to program switch “A” with a conditional

  • Desired Condition; Switch “A” can only be turned on while switch “B” is on

  • Thus; Switch “A” can not be turned on while switch “B” is off

  • Thus; Switch “B” must be on, before switch “A” is able to be turned on

  • Also; Turning on switch “B” does not turn on switch “A”

  • In other words, I have to turn on switch “B” before I’m allowed to turn on switch “A”

  • Don’t want to write software, just using smarthings

Can it be done?

Thanks for whatever info you’ve got.

We would need to know the brand and model of the switches, but if the switches actually control the current on the circuit branch, then it cannot be done.

That’s because all of the switches are designed so that they will control the current when they are physically manipulated at the wall to allow for their use in emergencies or when the home automation system is not operating.

However, if you are willing to use battery operated switches at the wall, and use in wall micros to actually control the current, then, yes, it can be done.

In most cases you would do this by using a battery operated smart switch cover which fits over the existing dumb switch.

The switch cover does not control the current directly. Instead, it sends a message to the hub which then sends a message to the device which does control the current, typically either a smart bulb or an in wall micro.

That gives us the opportunity to capture the request and put filters around it.

So that’s the first question: are these actual wired switches which are controlling a specific circuit branch? If so, it can’t be done.

But if you are willing to use switches which are not controlling the circuit branch directly, then there are some options. :sunglasses:

I think with a couple of virtual switches and webcore you could kind of do this. But it would mean writing a piston, which is sort of like writing software. This would only work for actions to the switchs via smartthings. Smartthings has no control over someone turning on a switch manually. You could have smartthigns turn the switch immediately back off, but probably not what your looking for.

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You wouldn’t need webcore for this, you can do it just with the official features in the V3 app or Even potentially with location.mode In the V2 classic app. Or if you want to pay for a third-party app, you could probably do it with smartrules for iOS or with sharpthings for Android. But again, only if the switch that you don’t want to have come on is not actually controlling the circuit branch.

But again, it can’t be done with a switch which does control the local circuit branch.