The Sonoff M5 Matter Light Switch

I’ve had Philips Hue Smart lights and various switches for nearly a decade now. I like them, they work reliably and allow me to perform some various lightweight automations that I find convenient. They’re quite pricey, the bridge only supports a limited number of devices, however their stability and performance have been good enough that I get no complaints from other occupants of the house.

My kitchen and dining room have spot lights — more than 30 of them, and trying to install Philips Hue GU10 spot lights in all them is far too costly — and would also exceed the capacity of the one Hue bridge I have, so I started off a small project of research, limiting myself to a £100 budget to find out what the way forward was with smart lighting that didn’t have the limitations of the Philips Hue, but that would provide me with the same level of reliability. I already have a Nest Hub (2nd Gen), and have been reading articles about Matter, which is supposed to be the industry standard that hopefully eliminates vendor lock-in and enables local control of smart devices. I know the Nest Hub itself is a Google device, and nobody knows how much longer Google will continue to support this, but since I have limited time to invest in this endeavour, I have convinced myself that if and when the time comes to move on from the Google Home, I would invest the necessary resources to adopt Home Assistant, ergo, I am not heading towards an unrecoverable dead-end.

Just for reference, since the stability might vary depending on the kind of wifi network you have, my home network is a Wifi 5/6 “hybrid mesh” system, with the 2.4Ghz band separated from the 5Ghz band. I called it “hybrid mesh” because it is a hodgepodge of various units acquired over time. Three out of 4 access points are Linksys Velop, Meshed, with support for 802.11r Fast-roaming enabled. Two of those Linksys were bought as a pack, two of them are hardwired, and one of them is using wireless backhaul. The fourth access point is a Fritzbox 7530AX that was issued by one of my ISPs in the past. Two out of 4 of the access points are Wifi 6 capable.

I tried the Wiz GU10 Smart LED Bulbs, two of them. They were on sale at the time, and cost me around £7 each. These paired fine with my Nest Hub over Matter.

At £7 a bulb, these were cheaper than Philips Hue, and as I understand, made by the same parent company as Hue, but still quite expensive considering the number of bulbs to handle. I also had concerns about my consumer-grade wifi’s performance with so many 2.4Ghz devices.

It would be far better instead if there were a wall switch that could control all the lightbulbs independently… and so I searched and found out many products claiming such support, and decided to try out the Sonoff M5-2C-86W, which is the UK spec version with two switches and 86mm width (to fit standard UK back boxes). This is quite a deep switch, and won’t sit comfortably in most UK back boxes, so I had to order some light switch surrounds that gave me about 4 extra millimetres of thickness to allow these switches to fit well and have a decent finish.

Even though the light switch is advertised as being directly compatible with Matter, they encourage you to use their App, which kind of defeats the point of Matter, so I initially deployed without bothering to use their app. However, I encountered several stability issues with wifi: The switches would periodically become unresponsive, and you would have to reset and re-add them to the Nest Hub again as new devices — about once a week.

This was a deal breaker for me, and I was close enough to removing them and filing the project off as a failure to be retried in a year or two when the ecosystem had matured a bit more, but I decided to pair with the manufacturer’s recommended app and check if there were any firmware updates. It turned out there was a small revision which fixed some unspecified bugs (their release notes are not helpful), but the net result was that the switch has remained stable and responsive as a Matter device in the Nest Hub for nearly 2 months now since I performed the firmware updates.

Verdict

In summary:

  • Build quality and tactile feedback can be improved: it is not as good as the products from the Philips Hue, or the Schneider Electric dumb switch it replaced, but it functional, and we are able to put up with it for the smart functionality. I expect they will come up with better revisions in the future, or some competitors will outdo them.
  • Stability and reliability is great after upgrading to firmware 1.1.0: out of the box, it was unreliable, and it doesn’t support Firmware Updates via Matter/Nest Hub. If you bought one or more that shipped with older firmware, you have to setup an account on their eWeLink app and update each manually, before you link them to your Matter controller of choice.

After firmware upgrades, I would recommend this switch to someone who was looking for a matter light switch.

Make sure you buy the one with the right specs for your home, because they have a lot of different specs for the same named switch, and I suspect this is the root cause for why Amazon has flagged the product as having a lot of returns.

It has worked well for me, and I find myself hoping they or someone releases the same switch, but with dimmers instead of simple on-off toggles. That’s the next thing I would like to add to my smart home — assuming the Matter Protocol even supports such a thing.