Is it possible for the hub to transfer outdoor temperature from a physical sensor to a thermostat?


(J-F) #1

Hello there,

I’m looking for ways to display actual outdoor temperature on a thermostat LCD screen.

So far, I have tried association between a multi-sensor device and the thermostat.

I have limited success with this approach since the multi-sensor I’m using only supports 1 association group with a maximum of 5 NodeIDs. Another sensor I have is a non-listening device, therefore I’m having trouble getting the association to work properly.

My goal is to use the same outdoor sensor to send its temperature to 10-12 thermostats.

I was wondering if it’s possible to ask the hub for the outdoor temperature.

Any idea anyone?

P.S. Also, if any of you have good ways to perform association between a multi-sensor and a thermostat, feel free to share your ideas.


#2

First, it depends on whether the thermostat itself allows for manipulation of its own display with outside data. Most don’t. There are a few industrial ones that do, but they come with their own remote sensors for just that purpose.

Anyway, let’s start with the basics. What’s the exact brand and model of the thermostat?

(Also…zwave direct association is typically limited to 5 devices. Just a protocol convention to reduce memory requirements. So you will run into that a lot.)

As far as weather information sources, you can use weather underground as a web service, lots of examples of that, just search the forums.


(J-F) #3

Hi,

The thermostat is currently under development, and we are willing to have an external outdoor temperature to be pushed to our device. The source could be a weather app or a sensor.

We are currently investigating the possibility to use physical outdoor sensors.


#4

If you’re building your own, zigbee is the usual choice for outdoor sensors over zwave. For one thing, it operates better through rain.


(J-F) #5

I know that, but we are currently developing a Z-Wave platform.

Do you know if it’s possible to query a Z-Wave hub for an external temperature?

Or is it possible to configure a Z-Wave hub to send the outdoor temperature to its devices?


#6

Same answer as above.


(J-F) #7

What about SmartThings hub?

The Keep Me Cozy II Smart App is to have another sensor to replace the embedded sensor in a thermostat.

This is not want I want to achieve.

The thermostat I’m developing has its own internal sensor to display the indoor temperature.

But on the LCD, there is a place to display the outdoor temperature. The thermostat will not come with an extra sensor. It will rely on the network to provide the outdoor temperature.

My questions are the following:

  1. Can SmartThings hub send the Outdoor Temperature received from a Multi-Sensor device to a Z-Wave Thermostat Device on its network?
  2. Can SmartThings hub send the Outdoor Temperature fetched from a weather service to a Z-Wave Thermostat Device on its network?

#8

I just answered this in post 5. Weather as a service in SmartThings typically uses Weather Underground.

See, for example:

Or this code example:


(J-F) #9

I installed the Smart Weather Station to my SmartThings hub.

It does display the temperature on the SmartThings app, no issue.

But what I want to achieve (and this is where I need support) is how to make the SmartThings hub to SEND that temperature to a thermostat device?


#10

That sounds more like a SmartApp coding question than a device integration question. Perhaps if you ask in that category you’ll get more answers.

http://community.smartthings.com/c/smartapps/writing-smartapps

It may also help to understand that the version 1 ST hub is just a radio station. It receives strings of data and it sends them out.

The logical processing of that data occurs in the ST cloud.

So you’re asking a coding question, not an antenna question. Cloud, not hub.


(J-F) #11

Well, yes, I may ask for the SmartApp coding if there is no other solution.

But it’s more of an integration question: is it possible to do what I describe?

Is is possible, in a SmartThings environment, one way or another, to have a temperature being sent from one device to another through the SmartThings hub?

Can the SmartThings hub receive a temperature from a device and transfer it to another device?

These are the answers I’m looking for.

I’ve already proven that it works using the direct association, but I’m limited to 5 NodeIDs and it does not involve the hub.


#12

The radio will send whatever bytes you tell it to send. It doesn’t know or care about their content. it just has to fit a known message format.

What’s the zwave device class your thermostat will be certified as?


(J-F) #13

The thermostat will be a generic thermostat v2.


(J-F) #14

I don’t know how SmartThings is designed under the hood.

So far, I’ve seen many devices displayed altogether on the SmartThings mobile app, but I haven’t seen any interactions between the devices THROUGH the hub.

I’m looking for a way to tell SmartThings to take temperature from device A and send a temperature report to device B.


#15

SmartThings is certified as a zwave controller for the Basic command set. That’s what’s “under the hood” for your situation. You’ve read the ST developer docs, right?

http://docs.smartthings.com/en/latest/getting-started.html

If your device is a zwave certified thermostat, you can send it a supported zwave command.

How you get the content of that command is up to you. Typically through a SmartApp, which is why this is a coding question.

The hub just passes on the messages, it doesn’t create them. So you more likely have a SmartApp that gets the temperature from Device A, then formats a message for the hub to pass to Device B. The hub just passes along the messages the SmartApps tell it to pass along.


(J-F) #16

Thank you @JDRoberts. I will pass along my questions into the Smart App forum.


(ActionTiles.com co-founder Terry @ActionTiles; GitHub: @cosmicpuppy) #17

Gosh… Quite a long thread when the answer is YES.

Any Devices (“Things”) connected to your SmartThings Account (the hub is just a transmission layer and doesn’t do any processing) can interact with each other, but ONLY through one or more SmartApps. (Devices cannot (or should not) directly interact with each other.)

This includes reading the temperature value of a temperature sensing device and sending it to a value displaying device.

The other thread gives a two line example: subscribe to the sensing device, and execute a Comman, or perhaps a direct Attribute update Event, to the display Device.


#18

Whoa!

Devices certainly can interact directly. Association in zwave, Binding in zigbee.

It’s just that’s not typically how you pass values like temperature.

(See what happens when you mix coding and device integration discussions! :stuck_out_tongue_winking_eye: )


(ActionTiles.com co-founder Terry @ActionTiles; GitHub: @cosmicpuppy) #19

Yes, but I guess I mean within the specific context of within SmartThings.

I just don’t know what terminology to use to be accurate, but I was attempting to simplify the model.

SmartThings Device Handlers cannot (or should not, per Device Type certification guidelines) interconnect Devices directly with a few very limited exceptions.

Associations & Bindings are not SmartThings features or tools, as far as my definition is concerned.

Whatever.


#20

See the last section on this page. It’s definitely part of the ST codebase, as it should be. (The Minimote, among other devices, wouldn’t work in SmartThings without it.).

http://docs.smartthings.com/en/latest/device-type-developers-guide/z-wave-primer.html?highlight=association