Sonoff ZB Micro did it! (and bonus ZigBee device)

Once upon a time, I received a Sonoff Micro – a WiFi-enabled USB relay. It was a very peculiar device which I promptly improved with an angle grinder and added USB-C capability. To make it smarter, I also created a Tasker charging profile, that would make the overnight charging easier on the battery. All this modding and destruction didn’t put off ITEAD from sending the new Sonoff ZB Micro to abuse! I’ll bundle this with one more ZigBee device from them!

Sonoff ZB Micro & new Sonoff Contact (SNZB-04P)

My biggest complaint about the original Micro was the lack of data passthrough. In my review, I uncovered a software interface that supported 4-channel relay switching. It looked like the feature got dropped in development. I have Sonoff ZB Micro in hand and while I’m excited about the ZigBee version of this silly device, I have one question:

Does it support data transfer?

YES!

I plugged my OBSbot Tiny 2 camera to see if I could stream the video through this little relay and just like that, I was able to cut the power and data transmission on demand! Neat!

Charging

Sonoff ZB Micro costs $12.90 and has more tricks up its sleeve, as this time around, this little USB-A relay packs a charging punch. It can deliver up from 5-22V and up to 4.6A of power. That makes the Sonoff ZB Micro rated for 36W with support for QC 3.0 charging standard. No more power bottlenecks associated with the original Micro.

Since the box mentioned QC3.0 – my next step was to check that claim and I used one of my USB testers to verify the voltage, as well as the ability of my Xiaomi 14 to negotiate the fast charging.

My phone quickly negotiated QC3.0 and started to charge accordingly. Remember, to take advantage of the QC, you need a compatible USB charger, Sonoff ZB Micro isn’t able to magically generate a charging standard! Poking with the USB tester reveals that my charger ramps up the voltage to 12V as per spec and continues the charge at 9V.

Other features?

Nothing else has changed. Sonoff ZB Micro is still a bit awkward to connect directly to a USB-A port without obscuring nearby ports or just generally getting in the way! Fortunately, this can be easily bypassed by buying a USB extension (check out these on Amazon). The USB port supports USB 2.0 data speeds (up to 480Mbit/s).

Aside from eWeLink/ZigBee controls (note that Sonoff Micro requires Sonoff ZB Bridge/Sonoff ZB Bridge Pro/Sonoff USB dongle/iHost) it can be controlled with a physical button. I have a sneaking suspicion that it will simply show up as a ZigBee relay if I’m going to connect it to other ZigBee ecosystems.

Use cases?

At first, I had no idea how I could use Sonoff ZB Micro in my smart home. I could modify my overnight charging profile and link this with Tasker’s ability to read alarms to come up with an even smarter version of this project, but modern phones are already pretty good at managing night charging as is.

I sat at my desk thinking, where else I could use a USB relay. It dawned on me, that without a special hat or a hardware hack, it’s almost impossible to power on a Raspberry Pi board remotely. Sonoff ZB Micro could solve that!

Another area where Sonoff ZB Micro could be useful is 3D printing. I made several mods in the past, that would integrate Octoprint/Klipper board with my 3D Printer. Each time I had to link a USB power supply to a smart relay to turn on my print server with my printer. With Sonoff ZB Micro, I could do that independently.

Sonoff ZB Contact

In my Xmas Bribe video, I also received the new revision of the ZigBee contact sensor from Sonoff. They asked me to keep it “secret” while they iron out the kinks – but now it’s time to talk about it too. In line with all “P” series sensors, SNZB-04P costs $10.90 and has been re-designed to fit your home better. Is it better than the very square SNZB-04? I’ll find out!

So far, the new Sonoff ZB sensor lineup includes:

• Sonoff Button $9.90
• Sonoff Temperature and Humidity sensor $10.90
• Sonoff Presence sensor $14.90
• Sonoff PIR sensor $11.90
• Sonoff Contact sensor $10.90

If you want to know more about the latest Sonoff range, I covered new sensors in this post, explained why the Sonoff Presence sensor is different here, and tested the Sonoff PIR in this article.

Sonoff ZB Contact is more round and this time around contains a tamper protection plunger at the back, which will tell you if someone tries to remove it. It is also powered by a new battery: CR2477 – which is hard to remove, and it’s really chunky. ITEAD claims up to 5 years on a single battery which is impressive!

Pairing

Looks like the pairing process has changed slightly for these devices. A QR code needs to be scanned (a new thing for ZigBee-enabled devices) then the eWeLink app prompts you to press the button and select the existing hub that I’d use to connect to Sonoff ZB Micro. This process feels very similar to how Matter devices are paired. I don’t think switching over to this method is a pure coincidence.

Both devices have paired quickly with my Sonoff ZB Bridge Pro and I was able to use them in seconds.

In eWeLink

Sonoff ZB Micro

Other than power-on state and inching, Sonoff ZB Micro doesn’t offer anything extra. The usual options are available thanks to the eWeLink app like timers, schedules and loop timers. The relay is as simple as it gets.

If I’m completely honest, I’d love to see the ability to disable data lanes only, but I’m grateful that I can use this little device with webcams, microphones and whatever else is using USB for data and power. The relay is completely silent.

Sonoff Contact

Sonoff Contact sensor is also a one-trick pony. It reports back the state of the contact sensor alongside the battery life and signal strength. Contact sensor triggers when the magnet is at least 4cm away from the unit, and registers the closed state when the magnet is as close as 3cm.

I was confused at first, as to why the tamper button doesn’t trigger any notifications. After a trial and error, I discovered that the action is available via the Scene menu – and once the sensor is selected as a trigger, the option Removed is available to be linked with other eWeLink smart actions.

In other ecosystems and Z2M

As both devices feature ZigBee protocol, I had a choice to add it to Tuya, enable with with my Alexa Echo Hub with Thread/ZigBee compatibility and even try the support for ZigBee2MQTT with a custom coordinator.

In Tuya

Sonoff ZB Micro pairs in seconds and shows up as a smart plug. There are no extra settings, so I can only turn this thing on and off or use the Tuya app Scene panel to automate it further with the Tuya ecosystem.

Switching over to the Sonoff ZB Contact sensor, I see a similar story. The device shows up in seconds as a contact sensor and works just as well as in the eWeLink app. I do not have access to tamper settings in the advanced menu or through the Scenes panel like in the eWeLink app.

With Alexa (directly)

Next up was the Alexa ecosystem. I used my Echo Hub to test 2 new devices and see how nicely they play with the ecosystem. I expected similar results as in Tuya. While the paring process was significantly longer (about a minute) both devices paired as expected. Micro was exposed as a socket, and the contact sensor as… a contact sensor.

With ZigBee2MQTT and NodeRED

I didn’t expect them to work on launch as device IDs are not linked to converters, but as these are simple devices, that’s easy! To my surprise, Sonoff ZB Contact worked out of the box (including tamper support), but Sonoff ZB Micro had to be hacked in.

Sample output from Sonoff ZB Contact:

{
    "battery": 100,
    "battery_low": false,
    "contact": false,
    "linkquality": 83,
    "tamper": false,
    "voltage": 3100
}

After adding ZBMicro with the converter from below, I got it to work and even enabled power on behaviour:

{
        zigbeeModel: ['ZBMicro'],
        model: 'Sonoff ZB Micro',
        vendor: 'SONOFF',
        description: 'Zigbee USB-A relay)',
        ota: ota.zigbeeOTA,
        extend: [(0, modernExtend_1.onOff)()],
        configure: async (device, coordinatorEndpoint, logger) => {
            // Unbind genPollCtrl to prevent device from sending checkin message.
            // Zigbee-herdsmans responds to the checkin message which causes the device
            // to poll slower.
            // https://github.com/Koenkk/zigbee2mqtt/issues/11676
            await device.getEndpoint(1).unbind('genPollCtrl', coordinatorEndpoint);
            device.powerSource = 'Mains (single phase)';
            device.save();
        },

Once restarted, Sonoff ZB Micro would report as follows:

{"linkquality":80,"state":"ON"}

Final thoughts

I hope this article will help you decide if these two new devices are useful for your home automation. Stick around, and you might see me adding USB-C support with data passthrough or even getting more creative with Sonoff Contact. If you have other ideas on how Sonoff ZB Micro could be utilised (bonus points for using USB data lanes), then leave me a comment in this Reddit thread.

🆓📈 – See the transparency note for details.