The Ultimate Smart Home Hub? SMLight Ultima 3 Zigbee Thread & Z-Wave Radio

I’ve been running my own smart home system for years now and frankly love having everything truly under my control. It can be a bit of a faff to get everything connected though, especially if you want to use more than one smart home protocol – ie Zigbee AND Matter-Over-Thread, or even Z-Wave – and you’ll often find yourself with multiple dongles and split solutions. Luckily, thanks to SMLight and their Ultima 3 hub, that might just be a thing of the past. This funky looking spaceship of a router is a remarkably open and approachable multi-radio hub that is upgradable, immensely feature rich, and feels like the perfect one-stop shop for pretty much all your smart home needs all in one box. That’s quite the deal! Let’s take a closer look at this thing so you can see why I’m so impressed by it.

SMLight isn’t new to the smart home game – this isn’t their only Zigbee or Thread radio – so they are properly experienced when it comes to making a hub like this. This though is a step above the rest. From the outside it looks a little funky – a bit alien spaceship-y for sure – and especially when you fit the two long antennas on the back you’ll struggle to not see a spaceship, and it’s even more clear when the LEDs turn on. Besides the styling you get a USB A port, two type C ports up front, one in the back, an audio jack, and an ethernet port. There’s also two circular punch-outs on the sides, and weirdly there’s a slot that looks like it could be for a microSD card, but it doesn’t look like there’s a port inside for that. There’s also an IR receiver on the front, and an IR LED on the top next to three incredibly small and recessed buttons. Oh, and from the bottom you’ll find a few mounting positions, and an arduino-style header.

The most interesting thing though is that they actually encourage you to open it up as it’s only a handful of clips around the edge, and once you get the shell open you’ll find the board is full of headers and markings for add-ons, because this isn’t just a sick multi-radio hub, it’s an UPGRADABLE multi-radio hub. Let’s focus on what’s on the board first though. Under the shield you’ll find an ESP32-S3 (the dual core one) which acts as the main processor – the core. At the back you’ll find two radio modules. One is a Texas Instruments CC2674P10 which is the Zigbee-only radio, and the other is an EFR32MG24, which can either be a second Zigbee radio, or can act as your Thread radio. Having both of these on one board means you don’t have to deal with the frankly massive headache that the multiprotocol firmware for the EFR32 is, but it means with a single cable (more on that in a sec) you can have BOTH Matter-over-Thread AND Zigbee networks hooked up to Home Assistant at once. That’s pretty sweet – but of course it gets better.

See this has a number of optional add-ons, and thankfully SMLight sent me one of each to show off here. First, and I’d argue most importantly, we have the PoE add on. This is what lets this be a one-cable solution. Assuming you have a PoE switch, or you pick up a PoE injector, having this powered over the same ethernet cable that’s giving you the data connection is amazing and means you don’t have to deal with passing devices into Home Assistant if you’re running it in a VM like I am. It’s all done over the network. Next is the mic add on. This can already act as a smart speaker with the headphone jack on the back, but the mic add-on should let it do even more. To be clear, in its stock configuration the mic won’t do much. You need to be running ESPHome firmware to let it do something for you, but if this happens to be in the same room you’d want to use voice commands, you absolutely can make this act the same as the Home Assistant Voice PE and listen for your voice commands. The only caveat there is that this doesn’t have the same XMOS chip onboard to do onboard voice processing so that will have to be offloaded to your Home Assistant server. Still, it’s a cool option to have available. Next though are the two optional radio slots. Yes. Two MORE radios can fit in here. One I’ve already mentioned, Z-Wave, which here in the UK is a pretty rare find, but I know across the pond is a little more common. This is what one of the punch-outs is for, and what one of the two extra antennas are for too – just make sure you pick the 900MHz one as that’s the frequency Z-Wave uses. The other one though is a real surprise – it’s a 4G modem! There’s a sim card slot here, and yeah, you can make this either your primary or fallback WAN solution too. That’s pretty incredible to have all in one device! Oh, and they also threw in another Zigbee USB dongle for good measure which can be hooked up to the USB A port. Who doesn’t need three Zigbee radios?!

In terms of setup I went with the PoE addon and a small patch cable from my Unifi Switch 8 PoE switch, and then headed to the IP address. From there you get the web UI. Immediately you’re hit with the dashboard which pretty much tells you everything that’s going on with it – firmware versions, temperatures, modes, the lot. The most important page though is the Mode tab. This is what lets you switch what each radio does, and what main connection mode you’re using, if Bluetooth Proxy mode is enabled, and if the Ethernet to Wi-Fi bridge mode is enabled. Let’s look through some of those options. For the EFR radio you can have this be your Zigbee coordinator, just a router, have it run thread with a remote border router (ie it’s just a thread node), or have it run Thread AND be the border router – the ideal choice in my opinion. The second radio can also do Thread, but you’ll likely want Zigbee to run on this one instead, especially as this is the one that can run in Zigbee hub mode. This is cool, basically it cuts out the need for an external host, as your Zigbee devices actively connect to the Ultima, and you can even run basic (if not exactly user friendly) automations and scripts on-device. Now personally I like Home Assistant a little too much to ever use it in this mode, but it’s pretty cool that you can.

There are settings for everything – network, MQTT, 4G/LTE, Z2M and ZHA (we’ll come back to that one in a second), IR Learn & Replay (again coming back for that), Audio, Ambilight (the LEDs), Security, VPN, DDNS, USB Passthrough, Open Thread Border Router, and BLE, but at least for me the important pages are the Zigbee one and the IR one, so let’s start with the former. There’s a few ways you can connect this to something like Home Assistant. You can just hook it up with USB and kinda use it like any other dongle – perhaps a dongle with its own IP address and network access, but still. Or if like me you’ve got the PoE option and it’s hooked up that way, you can have this be a networked dongle, pointing either Zigbee2MQTT (Z2M) or Zigbee Home Automation (ZHA) at the relevant port for each radio. What’s even more cool is that while it should be fairly easy to migrate from your existing coordinator to this, their UI offers IEEE address spoofing to effectively instantly switch all your devices over without having to re-pair anything. Just the ole switcheroo. Fun!

The IR page is also pretty sweet. Thanks to the infrared receiver on the front and LED on the top, you can have this capture IR signals (it does it automatically), save the commands to automations in Home Assistant, then the Ultima will replay those commands on request. This basically lets you turn non-smart devices into smart ones, all from just having this thing in the room. For, say, an older air conditioner or TV or sound system, being able to control them remotely is really cool, even if you don’t get direct feedback that the commands worked (ie you can’t see in Home Assistant that your TV is now off or your air conditioning has turned on as an entity state). Still, this feels like such a cool addition that SMLight absolutely didn’t have to include, but the Ultima is all the better for having it.

Naturally you can install SMLight’s Home Assistant integration that lets you control at least some aspects of the Ultima, although a number of features either don’t work well or are missing. You can control the onboard LEDs though, so from an automation perspective using it as a notification light is pretty sweet – have it flash when your doorbell has been pressed, or set to a specific colour when an automation is triggered or an entity changes state. Lots of fun you can have with that. You can restart both radios (although which is which is hard to tell since they are both listed as “Zigbee”), but things like changing radio modes or updating anything isn’t available through the integration. The IR receiver also is just a notification entity rather than a data entity, which is a bit of a shame. 

It is worth noting that this thing does have a few limitations. If you want to use Bluetooth Proxy mode (essential if you want to pair HomeKit Thread devices), you’ll need to flash the ESPHome firmware on the ESP32-S3 main core, which does still retain things like Zigbee support while using Bluetooth Proxy mode, but loses the web UI and a lot of the configurability, so I’d perhaps use that at your peril. I’d like a Bluetooth Proxy add-on instead of Z-Wave personally. I should also note what feels like the Ultima’s biggest flaw, a lack of documentation. Having to search for the documentation on how to install the add-ons (especially since they are all installed upside down from how you might expect, a mistake I almost made with the microphone add-on until double checking) or having to guess how some functions work because there just isn’t an actual manual for the Ultima available – hell their own web UI points you to their SLZB-06 manual (which doesn’t load properly for me) to describe how to flash the ESPHome firmware, except I can’t seem to find the Ultima ESPHome firmware either in the linked repo nor on their own flasher website! To say this feels like an early option feels like an understatement, although Smart Home Scene had one of these in April and it’s now August, so it isn’t brand-spanking new at least. 

I should also make it clear, mostly because it took me far too long to truly understand this, that this isn’t the SMLight SMHub. The SMHub is an entire Linux based PC – with all the same multi-radio features mind you – that runs, well, Linux. This is much more of an accessory to your existing HA server than the SMHub since that basically acts AS the server. It’s best to not get the two confused, and actually Smart Home Scene has an excellent guide to what each of SMLight’s models do, so I’ll link that in the description for you.

So, this is basically the ultimate smart home hub then. It’ll do all three main protocols (with an optional upgrade anyway), it can act as a 4G LTE backup for your network, make dumb devices smart controllable through IR, it’s impressively open (the SLZB-06 firmware is open source and I’m sure this one’s will be at some point), and the fact this is all customisable and controllable including through ESPHome makes it an incredibly impressive bit of kit. Pricing is obviously a key thing, and on that front I’m a little confused. The only UK seller SMLight lists on their site as a “where to buy” option for the UK has it at £135, but their Aliexpress store will happily sell you it for as little as £40, with the most expensive combination (all the add-ons included) being just £72.94 (marked down from around £79). I’m going to assume the AliExpress price is the one to trust since it’s their own storefront, and so yeah if you want a three-radios-in-one, PoE powered, mic’d up, 4G LTE backup’d smart hub, £80 is a pretty insane deal. Even if you just want the PoE add-on, £50 when not discounted is a killer deal for a multi-radio setup like this for sure. A regular Sonoff Zigbee dongle sets you back between £30 and £40, so a tenner more to basically get two of them AND cool features like the IR blaster and status LEDs is pretty sick. It also opens the door for future upgradability with those modules, so to say I recommend this feels like an understatement. This thing is incredible, and while I’ve already got a pretty stable setup I don’t fancy breaking just yet, if I was starting fresh I would absolutely use this as my hub of choice. 

Oh, and as a small aside, the UK store SMLight link to, Zigbee Smart, do some hilariously dumb things. First, if you switch tabs the tab’s title instantly changes to “Come back” – how desperate – and even funnier they have one of those stupid “X customers viewing this product” counters on the web page, except while we all know those counters are fake, they’ve taken it to the next level by having it pick a random number every 30 seconds or so, often gradually increasing over time too. But, like, the swings are WILD. 18 customers are viewing this product! Now it’s 165! Now 200! Now 10. I recorded this for a couple minutes so I’ll speed this up so you can laugh at how stupid this is.

Oh, and one final thing I want to note. SMLight is a Ukrainian company, and given the horrors I know they’ve been facing for YEARS at this point, supporting Ukrainian businesses has an extra bit of good attached. I wish them, and the people of Ukraine, the best, and hope they stay safe.