Hi
I have a SmartThings Hub with over 90 Zigbee or connected devices (such as Merross).
I also have an Eero 6 Pro mesh network that covers the house.
The eero has a thread network which is activated.
However, I bought a Matter device (a door sensor) and it can only be added in range of the central ST hub and is not detected close to an Eero device.
How can I get ST to use the Eero Thread network so that I can have a perfectly connected home automation system without black spots?
Thank you.
Have you tried adding the door sensor using the Alexa app first? The alexa app should be able to add it via the eero Thread network. Once added to the alexa app, you can share it to the SmartThings app using Matter multi admin.
I will try that – thank you
What is the specific brand/model sensor you purchased? Which ST hub do you have? What model Eero Pro device do you have?
Are you trying to use the ST app to commission the sensor or the Eero app?
Apologies. It’s an Aqara matter contact sensor. I have the Samsung SmartThings hub v3. Eeros are Pro 6’s. I have tried connecting it via the hub (it works in close to it but not where I need it to be) and I’ve tried via the Alexa app as suggested earlier.
The second method proved a better option but when it got to the stage of the Alexa app asking for the Thread network password, it failed to connect saying it had to be closer to the eero (2m) or on the same network (I only have one).
Interestingly, when near the ST hub the Alexa app offered 2 Thread networks. The ST one and the Eero one. Whereas, where I need I use it I only get the Eero one is seen. So much for home integration 
So, you’ve tried commissioning it with the ST app and the Alexa app, right? If you want it on the Eeros Thread network, why wouldn’t you commission it with the Eeros app?
Unless things have changed very recently, the eero app is not a matter commissioner.
They recommend you use other apps, such as Apple home or the Alexa app. (Alexa and Eero are both owned by Amazon.)
And the technical details on their thread support. This is very technical. 
There is no way I can see to do it on the Eero app. Or am I wrong?
JD’s post is saying that the Eero app doesn’t support Matter commissioning so you need to use an app that does such as the Alexa app, ST app, etc.
With the sensor near the Eero router, can you select the Eero Thread network from either the Alexa or ST app and supply the Eero Thread network key?
Yes. The Alexa app offers the available thread networks. But it doesn’t connect to the device when I enter the thread network password.
You should be scanning the QR code on the device when pairing it.
Hi. No QR code. Only digits to enter.
Model of the Aqara sensor?