I have an unreliable zigbee 2 gang wall switch which randomly goes offline from time to time. I’d be very keen to replace it with something more reliable that works with SmartThings. I thought of a matter one using thread or WiFi, but I need it to be no neutral (and fit in a 25mm back box) and I think thread has lower power requirements than WiFi so would be less likely to need capacitors etc.
I’d been assuming for about a year now that these would arrive on the market imminently, but I’ve not see any yet, is there some delay on this or are there technical constraints making this harder?
I’ve searched in multiple places for quite a while now but haven’t found anything that ticks all the boxes above. do matter and thread based wall switches have a technical limitation making it harder or not feasible to produce in a no neutral version ? Matter has been around and while now, surprised these aren’t available
No technical limitation, but the market demand just isn’t there yet. There were multiple issues with the initial thread implementation for matter, as you might have followed in the matter discussion thread in this forum. It’s really only been the last four or five months that those have been worked out, and it’s still not perfect when it comes to multiple thread networks in the same fabric.
Matter - smart home connectivity standard (formerly Project CHIP)
And from a general matter standpoint, the assumption has always been that Wi-Fi would be used for mains powered devices and thread for battery powered ones. That’s the direction most of the manufacturers have gone.
With the exception of the brand new inovelli white series, there are almost no thread switches for the US market either.
I don’t personally have a sense yet as to whether this device category will ever pick up. But they certainly aren’t here yet.
Thanks for that. I was only fixated on thread due to its lower power requirements. I’d imagined it would be easier to build a thread no neutral switch that didn’t require a capacitor than a WiFi one which tend to need them.
And Eve home has just released its new matter over thread light switch in both Europe and the US. But it doesn’t meet any of your other requirements, it’s just single gang and does require a neutral. Still, progress.
Also, the need for the capacitor isn’t because of higher power requirements: it’s because of the way the internal radio is powered even when the switch is “off.“
Understood, but surely a zigbee radio requires less power than a WiFi one? I currently have two zigbee switches (no neutral) which don’t need a capacitor, most if not ok of the WiFi switches need a capacitor
It does, but it’s not usually perceived as a big issue in the light switch category. And that’s not the issue with powering the radio when the switch is “off“ it’s just a question of wiring.
You need to be able to get live power to the radio while The light is off. Many dumb switches are designed just as a cut out to the current. When the switch is off, no current flows through that circuit branch, but that means no current, so there’s nothing to power the battery. When a neutral is available, you can get the power for the battery from the neutral even when the light is off.
Interesting. I always thought you needed the neutral as a return path for the current draw from the hot. That way, even when the smart switch is “off” and no current is flowing to the load, there is current flow to power the radio.
Ok then there must be another reason then why the WiFi wall switches all seem to need a capacitor and the zigbee ones mostly don’t 
Hi,
Devices that do not use neutral and the load is resistive, such as a filament bulb, can work without capacitors since the neutral reaches the device through the filament or resistance of the load when de switch is off.
When the load is an LED device, which has a switching power supply to dc power the LEDs, then a capacitor is needed between N and L of the LED so that the N of the alternating current can pass through the capacitor and reach the switch.
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I have two zigbee no neutral switches
This one which works without a capacitor on 4 led gu10 bulbs. Although it locks up every 4 or 5 months needing reset, hence I want to replace it.
I also have this no neutral zigbee dimmer . Which has worked flawlessly for nearly 3 years without a capacitor . It controls 6 led gu10 bulbs
Are your gu10 led bulbs dimmable?
The ones on the dimmer are, those on the standard switch are not. Second link was linking to incorrect item in Amazon, I’ve replaced it with a screenshot
I’m waiting for this:
H2 EU wall switches: Three wall-mounted devices – the Light Switch H2 EU, the Dimmer Switch H2 EU, and the Shutter Switch H2 EU – were also unveiled. These are Thread- (and Zigbee) enabled wall switches that deliver manual control of lighting and other wall-mounted switch-based systems. They feature power monitoring and are designed to be used in houses with or without a neutral wire.
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Looks interesting. I don’t see any detail on the depth into the wall, which will be crucial for me. I await with interest 
Knowing if bulbs were dimmable bulbs is just trying to understand why the switches work without neutral and without a capacitor.
The electronic circuit of the dimmable ones is different and could allow the N to flow to the intensity regulator of the switch.
In the case of the non-dimmable ones, it could have to do with the fact that when using 4 bulbs in parallel, the impedance is divided by 4 and could allow enough current to pass through for the switch to work.
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@JDRoberts
Been thinking about this…
If thread was to be used for battery devices only then what would the thread “mesh” run on if the battery devices are “sleepy”. Surely you need some always on thread devices to propagate the messages to the hub?
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Sure, you need some, but the assumption initially I think was that those would mostly be the thread border routers, particularly smart speakers, which many people have more than one of already.
Hmm, I have 7 echo dots, 1 first gen echo, and two Sonos one with echo. None of which could act as thread border routers. 
True, like the SmartThings hub v2, the Echo Dots are unfortunately not Thread Border Routers.
At the time of this posting, here’s Amazon’s list of the Amazon devices that are:
What is a Thread border router and which Echo and eero devices work as Thread border routers?
.
Thread border routers are required for devices that use Thread to talk to other non-Thread devices, and be controlled by voice assistants, like Alexa. Select Echo and eero devices have Thread border routers built in: Echo (4th Gen), Echo Show 10 (3rd Gen), Echo Show 8 (3rd Gen), Echo Hub, Echo Studio (2nd Gen), Echo Studio (1st Gen), Echo Plus (2nd Gen), eero Pro 6E, eero Pro 6, eero 6+, eero 6, eero PoE 6, eero PoE gateway, eero Pro, eero Beacon, and eero Max 7 have built-in Thread border routers.
Alternatively, there are a few Matter over Thread mains powered devices that act as Thread repeaters, most notably the Eve smart plugs which are available in both US and UK models.
These are thread repeaters but not thread border routers.
UK version:
OnVis has a less expensive version available for both the US and UK, but without energy reporting. Sold in a two pack, so the per unit price is less than half of the Eve model. Again, not a Thread Border Router, just a Thread repeater.
UK version:
Therefore, as the S4UK smart plug is plugged into a power outlet, the S4UK will act as a Thread Router to extend the signal of the Thread network to other parts of your home. If one device on the Thread network is beyond the range of the Alexa/GoogleHome/Homekit hub, just add one or more S4UK smart plug to expand the Thread network range. The Thread network will become more robust and the coverage will be wider with each additional Thread device.
So if you find you do need some thread repeaters, there are a couple of choices. 