Using z-wave light switch to turn on secondary outlet lamp?

(Mikespry) #1

sorry if this is an obvious question…still new to the smartthings hub.

I thought this would have been easy but I’m not seeing how this can be done?
I have a room which has a z-wave light switch that controls an outlet. I also have a secondary lamp that is plugged into a regular outlet with a wemo (could be z-wave) outlet plug.
i would like to be able to have the secondary lamp turn on/off based on the state of the main z-wave light switch…

is this possible to do?


Evolve LTM-5 transmitter to LRM-AS association
(Florian Z) #2

Absolutely, check out the “The Big Switch” SmartApp located under the “Convenience” category.

(Impliciter) #3

It is possible but be aware that not all switches instantly report their status to the hub. Therefore, your control may not be instant and could be delayed quite some time.

(Florian Z) #4

Yeah, you’ll definitely see a delay due to your hub forwarding events through the internet to the ST cloud, which will in turn execute the relevant SmartApps, generate events, and send them back to your hub. I’ve seen the delay be as long as 5 seconds, which can certainly be annoying at times.

(Mikespry) #5

thank you @FlorianZ! totally missed it. can’t wait to try it out once i install the hardware.

(Mr Matt57) #6

I am trying to do something similar too. According to the device logs, it seems that z-wave devices go idle and stop reporting status. I have found that a .refresh() or .poll() command will wake them up and report status, but this doesn’t seem to be a viable solution for time sensitive actions. This goes for all my z-wave devices (Thermostat, switch and dimmer).

I am trying to figure out if this is:

  1. an inherent z-wave protocol/network limitation.
  2. a z-wave device implementation issue.
  3. a SmartThings hub issue.

I see a lot of conflicting information regarding “local” operation and the devices ability for “2-way” communications. All of the SmartThings Zigbee devices work flawlessly, but I can’t find any Switched/Dimmers available.

Is anyone having success with their z-wave devices consistently reporting local changes to their hubs?

(Duncan) #7

GE Z-Wave switches won’t send the hub a notification when they are switched (due to a patent encumbrance issue). In some situations, they will send out a broadcast beacon when they are switched, so if they are in direct range (not through a repeater), the hub can use that to know that they switched. Otherwise, the server will poll switches every 5 minutes, and the new “Labs” firmware 0.11.* polls them up to every 6 seconds.

(Chrisb) #8

@duncan, How do we get the labs firmware?

@mrmatt57, I have a program that I run called Wireless 3-way. It’s kinda like the Big Switch app that @florianZ mentioned earlier. The difference is that the Big Switch app has one master and one or more slaves. Only changes at the big switch change the others. With my app any switch will change any of the other switches.

I’m running this is two different places in my house. Generally I see a one second or less delay in the switch triggering. When I turn on one switch, the other turns on within one second.

As Duncan said, there is a patent issue where switches that don’t subscribe to Lutron’s patent can’t report back to a hub (any hub/controller) when they are physically pressed. SmartThings can get around this issue in some cases. When a switch is pressed it sends a node update through the network. SmartThings see this and says: “Ah ha! A switch may have been pressed”, so it does a poll of that switch to update data on it.

This gives SmartThings near-real time updated data, but it has limitations: First, it only works if the device is in direct communication with the Hub. Node upgrade broadcasts aren’t passed along the mesh so the Hub needs to see this device directly. Second, dimmer switches don’t play nice. In this case SmartThings is too fast. When smartthings polls that switch the dimmer is still turning off but isn’t all the way off. So ST thinks the switch is still on even though it isn’t. Third, Aux switches (in a wired three-way setup) do NOT send these node updates so they will never trigger SmartThings to poll the switch.

(Mr Matt57) #9

Thanks @Duncan, that explains why sometimes it work and sometimes it doesn’t. The additional polling will definitely help, I requested a hub upgrade.

Are there any switches/dimmers compatible with ST that either license the patent or provide similar functionality? It is hard to determine based on the specifications what is supported. So far I have tried Iris/GE/Jasco and Evolv without luck. I was hoping to dive in and automate my lighting, but I haven’t found the right solution yet.

@chrisb Thanks for the additional detail on the limitations and workarounds.

(Mikespry) #10

@Duncan @chrisb so if GE Z-Wave switches don’t subscribe to this patent, which switches do?
i was planning to overhaul my house with GE switches but sounds like I might want to rethink this if i want “switchWasPressed” events to be sent out?

(Duncan) #11

Leviton Vizia and Cooper Aspire switches license the patent, but I haven’t actually tried them to see if SmartThings sets the right association to get subscribed to the events.

(Mikespry) #12

figures, both cooper aspire and leviton vizia are much more expensive than the ge alternatives.
i’m somewhat disappointed that not all z-wave devices/light switches are created equal. one of the reasons i wanted to upgrade my whole house is so in various places i can control a main room light along with a secondary z-wave outlet lamp (if mainLightSwitch flipped then flip outletLamp kinda thing…) seems like without the direct switch reporting, it’ll introduce even more delay…

(Chrisb) #13


And you can guess why the most those are more expensive! They’re paying a royalty to Lutron! Which dumb… I mean isn’t communication between a device on a network and the network controller sorta obvious and a given? It’s dumb that the patent office would give a patent on this. But, that’s just the way it is.

As for the delay, I really don’t think this will be a problem. Like I mentioned earlier, I have some wireless 3-ways going where I hit one switch and it turns another on. Usually this delay is 1 second or less.

(Mikespry) #14

no kidding @chrisb!
it’s a real shame there is a patent on such a trivial and obvious action/event. i mean “press button -> trigger event” has been around forever!

i found this neat comparison chart if anyone happens to stumble on this thread: