Category Archives: Home Automation

Temperature and Humidity Monitoring in the Outbuildings – Thread Network Range Issues?

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The GL-S20 Thread Border Router and the two original Timmerflotte temperature and humidity sensors have been working fine. Once they came back into stock at the local IKEA I bought two further Timmerflotte sensors. One of those didn’t want to Commission (needs further investigation) but the other one did Commission successfully, at the first attempt, and took the expected firmware update.

While that third sensor has mostly been OK, it’s periodically dropping off the Thread network. The first time that happened I intervened with a power-cycle, which brought it straight back online, but on a couple of other occasions it came back all by itself.

Periodic connectivity drop-outs for the Timmerflotte sensor in the Ground Floor Store room

The main difference from the other two sensors is the distance from the Thread Border Router – roughly 16m, with one 100mm concrete-block wall in the way. Might that be the issue?

Thread networks are expected to operate in a ‘mesh’ topology, with mains-powered Thread devices acting as relays for the radio signals, between the central Thread Border Router and the (battery powered) End devices, so maybe one of those would help?

As a first step I’m going to try moving the problematic sensor a bit closer to the TBR. If that doesn’t work I’ll move the TBR much closer to the sensor (there are limited options because of the availability of wired Ethernet network ports).

Update: Moving the sensor about 1.5m closer to the TBR (but still on the other side of a wall) prompted it to come back online, so now it’s recording readings again. I’ll see if that proves to be a long-term fix.

The implication is that the drop-outs were indeed caused by a Thread network range issue – which implies the plan to locate the fourth Timmerflotte sensor even further from the TBR is likely to be problematic without some sort of network extender device. While not yet available in the UK, the IKEA GRILLPLATS ‘smart socket’ looks like it might be suitable (and not too expensive).

Temperature and Humidity Monitoring in the Outbuildings – Stage 3

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An earlier Post outlined the plan to use IKEA TIMMERFLOTTE Temperature & Humidity Sensors with a GL.iNet GL-S20 Thread Border Router in conjunction with Home Assistant, to monitor the environmental conditions in various parts of the Outbuildings – especially the unheated rooms which are open to the ambient conditions.

I got the TIMMERFLOTTE devices on-boarded to Home Assistant fairly easily and they even noticed they had a firmware update available and downloaded and installed that over-the-air – all without needing any other IKEA-specific ‘hub’ or similar devices. The on-boarding (“commissioning” in Matter terminology) requires a smartphone (iOS in my case) and makes use of some of the built-in Apple software to help the Home Assistant App handle the set-up. For that to work, the smartphone must (temporarily) connect to the same network subnet as both the Thread Border Router and Home Assistant.

While the devices worked fine when tested in the House, they were not working when moved to the Outbuildings – despite them being on the same network Subnet (which gets ‘stretched’ to the Outbuildings – albeit via a few Ethernet Bridges and extra network hops). This was puzzling because everything was expected to work the same in both locations. It turned out to be a firewall issue, related to the use of an extra IPv6 address range: in the House the network traffic only has to traverse the network Switch to get from the Thread Border Router to Home Assistant (so it doesn’t reach the firewall) but with the Thread Border Router moved to the Outbuildings the traffic is traversing the inter-building link so hits the firewall to get to Home Assistant – even though it’s on the same Subnet. Three firewall rules turned out to be required:

  • Allow IPv6 UDP traffic with Source Port 5353 (i.e. mDNS)
  • Allow IPv6 UDP traffic with Destination Port 5540 (i.e. Matter)
  • Allow IPv6 ICMP traffic – to permit Home Assistant to ‘ping’ the sensors for diagnostic purposes

It’s clear the Matter protocol expects a completely ‘flat’ network topology – which isn’t great from a security or problem-solving standpoint. A decent compromise is to have a dedicated and largely isolated ‘flat’ Subnet for Matter / Thread traffic – but to dual-home the Home Assistant server so it can also participate in Matter communications (while using its ‘other’ network interface for all other communications).