Issues with Sonoff SNZB-03 motion sensor

Lots of people have issues with these sensors btw: SONOFF SNZB-03 Strange Behavior · Issue #4874 · Koenkk/zigbee2mqtt (

I use zigbee2mqtt now, but I also had these when I had Deconz. Also acted strange there.

I used 8 of these sensors and some work fine while others have random issues. Like false triggers once a day, not triggering at all sometimes, or not sending the off-command after motion, leaving the lights on even when nobody is there. The 1 min cooldown wasn’t really an issue for me with my automations. But the other issues do break the whole point and reliability of home automation.

They’re nice if you have just started and don’t want to invest too much money yet or are still trying automations. But for homes where people live and you want stuff to ‘just work’ instead of having your lights turn off while still on the bathroom, these just aren’t worth the headache in my opinion.

I have solved all the issues with one simple solution. I purchased a Hue sensor. Yes they are expensive (€32-35 in stead of €9) but they work so so much better. I used 2 Sonoff sensors in each room, because I wanted to have a backup sensor since sometimes the sensors would’nt trigger on time or not at all. Now one Hue per room is enough. It’s extremely accurate, has great build quality and best of all: has a cooldown of 10 seconds that keeps extending if you keep moving. Also has a temp and lux sensor.

I just removed around 16-18 Aqara and Sonoff motion sensors and replaced them with 8 Hue motion sensors. After the first Hue I ordered 7 more the next day. Should have done this from the beginning. I use the motion sensors like 100 times a day, so cheaping out on these wasn’t smart in retrospect. Would have saved me a lot of headaches and even money with replacing faulty sensors and trying out different cheap brands (tried Konke, Blitzwolf, Sonoff, Aqara). I’m sure even Hue will get an occasion false trigger or glitch, it’s all wireless tech after all. But it works a lot more reliable and robust.

Btw: if you want the door sensor, do NOT get Sonoff. Opening has a one second delay before state change (closing is fine). Get Aqara instead, they work great :+1:t3:


The Sonoff motion detector that was causing me the biggest headache is the one in the bathroom next to my office, so what I ended up doing is creating 2 separate automations based on time of day (it helps if you’re “regular” :grinning:). Motion detected between 9-10 turns the light on for 10 minutes, and motion detected outside of those hours keeps the light on for 2 minutes.

For higher traffic areas like stairs, I replaced the Sonoff with Hue Motion sensors, those babies reactivate within a second and definitely worth the price.

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Same thing here. The snzb-03 worked fine for a few weeks then started with the false positives. Now after having re-paired it a few times (to a conbee ii) it doesn’t register anything at all…lol

For those of us that are stuck with them, I hope a modification method is eventually released because they would be a huge waste

It’s interesting seeing other folks having similar problems.

I have four SNZB-03 sensors, all worked fine for many months, absolutely faultless & great value.
I use them with a Conbee II stick & ZHA.

Then they started sending continuous on/off signals very recently all day & night, often seconds apart and as others have witnessed, the batteries took a hit due to increased traffic. No surprise as zigbee is a protocol aimed at low levels of signalling with simple payloads of data.

I have a different suggestion I’d like to put forward as the possible cause. The SNZB-03 all worked fine until the recent drop in temperature where I live in the UK. I’m wondering if these sensors are not suited to low temps. The worst affected sensor is in my garage where temp are often close to 0.C. Even in the house when temps drop overnight below 15.C I’m seeing noise on the state history. Instead of seeing bands of green no motion, I’m getting solid brown state of continous switching from no motion (green) to motion (red).

When temps drop my devices seems to send spurious & frequent motion detection. The colder the greater the issues.

I brought them all to a warmer part of the house and the issues disappear until temp drop at night.

Would like to hear if this is the case for anyone else.

As a comparision I placed an ESP8266 with a PIR in the garage and I’ve seen no spurious motion signalling. Not a perfect comparison in fairness as PIR units may differ.

My plan is to move away from using these fair weather SNZB-03 sensors unless anyone has a fix.

Maybe it’s just me & the place is haunted! :laughing:

Hope this helps, let me know



@ jazlichy
In a parallel thread on the SNZB-03, I posted my experience with trying to operate a SNZB-03 outside in a Minnesota winter, where there are extended periods of outdoor temperatures below 32F (0C).
This week, overnight temperatures are dropping to -10F(-23C) and daytime highs are just getting into the single digits above 0F (-17C).

I tested the 2 Sonoff SNZB-03 units I have.
The first unit I tested started self-triggering when the outside temperature dropped below 26F (-3C).
The second unit worked until the outside temperature dropped below 10F (-12C).
When I brought them inside, they continued to malfunction until they warmed up.
I noticed that when they were malfunctioning, their battery voltage was way down to around 50%.
As they warmed up, I watched the battery Voltage recover. The units functioned normally once the battery Voltage had recovered to around 60%.

I didn’t grab screen shots of the SNZB-03 battery Voltage when this was going on, but I have captured the battery Voltage graphs of Sonoff SNZB-02 temperature sensors during our cold weather this past weekend. Note how the battery Voltage kept dropping and dropping as the temperature fell.
Temperature below 10F SNZB-02 Temperature vs Voltage SNZB-02
I replaced the battery before the SNZB-02 battery went dead and I lost the data from the sensor.
The same CR2450 coin batteries are in all these Sonoff sensors, and I believe we can expect the same behavior in cold temperatures.

I looked up the specs of the PIR sensor I believe is in the Sonoff units (3 pin, through-hole, metal can, PIR sensor with square window on top).
It’s operating specs list functionality down to -40C!
If true, the PIR sensor shouldn’t be the failure point.

My conclusion is that the self-triggering is caused by sagging battery Voltage, due to cold, and the CC2530 Zigbee chip is probably rebooting over and over, transmitting the trigger signals over and over.

My proposed solution is to open up the unit and solder an external AA battery holder to the battery terminals. or
Two AA batteries (especially lithium AA batteries) should maintain a lot more reserve current when the temperatures drop below 26F (-3C), and thus the Voltage won’t drop to reboot levels, and it will continue operation in the cold. It will be ugly to have a battery holder hanging outside the unit, but I suspect this will solve the cold coin battery problem.


can the HUE sensor trigger lights other than HUE?

If you use ZHA, deCONZ or zigbee2mqtt yes you can. You’ll need a Zigbee coordinator (USB for instance) that works with one of those add-ons. You can get rid of your Hue gateway and control different devices with different sensors (kinda the whole point of Home Assistant :wink: )

But this topic is about Sonoff SNZB-03 issues. If you want more info and see what the differences are between those three solutions, see -> deCONZ vs ZHA vs zigbee2mqtt - Configuration / Zigbee - Home Assistant Community (

right now all i have is a ZOOZ zwave stick. when you say Zigbee coordinator, you just mean a zigbee usb stick right? wonder if it’s worth it as in Canada that Nortek usb is $120 by itself.

That Nortek USB stick is a combined Zwave/Zigbee stick. No need to buy that one if you have already a Zwave stick.

not much else available on…

@ xman111
Here’s a list of supported Zigbee adapters to act as coordinator:

I bought one of these from Amazon:

and followed this how-to for putting the desired base firmware into it:

It’s essentially the same board that Itead (Sonos) sells:

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For the reason of comparison to the Sonoff SNZB-03, I ordered one of the Philips Hue motion sensors to play with. I ordered the cheaper of the 2 Philips Hue models.
The motion sensor functionality has been excellent.
It resets it’s “occupancy” status within 5 seconds of the stoppage of motion.
The main downside is it’s $40US pricetag.
Philips Hue motion sensor card

I had not read about the Hue also having a temperature sensor!
The Hue temp sensor is reading about 3F degrees low, compared to a Sonoff SNZB-02 right next to it.
I’ve found that the Sonoff SNZB-02 temp sensors are pretty accurate, when comparing them to other temperature sensors in the same room.
The Hue hasn’t been in service for a full 24 hours yet, so the time scales on the temp graphs aren’t a 1-to-1 relationship. Just focus on the last 12 hours.
The Hue bottoms out at 62.6F and the Sonoff bottoms out at 65.8F.
Philips Hue temp history 2-13-2021
Sonoff SNZB-02 history 2-13-2021

I’ve just tested the snzb03 sensor with the Sonoff USB Dongle CC2531
and for some reason it keeps showing motion detection , same as with conbee.
It works unreliably even with sonoff zigbee dongle.

As far as I’m aware there is only one Philips Hue motion sensor, or is this very new? Do you have a link to this second model? Or do you mean the outdoor sensor?

Btw, you can calibrate the temp sensor if you use zigbee2mqtt by setting it a few degrees higher/lower. See >

I bought this:

This is the more expensive unit I saw.

I see it has AA batreries, vs the AAA batteries of the cheaper sensor.

Thanks for the info about tweaking the temperature sensor calibration.
To use zigbee2mqtt, I have to remove the ZHA integration and the Sonoff Zigbee Bridge, correct?
Or can they both zigbee2mqtt and ZHA exist on the same system?

Yeah, that’s the outdoor motion sensor (hence the name). Not really meant for indoor usage (overkill and too big as well).

You can’t use ZHA and zigbee2mqtt at the same time with the same Zigbee coordinator. So you will either pair all devices to ZHA, or re-pair everything to zigbee2mqtt (meaning to start over and naming entities as well).

Btw, don’t just install zigbee2mqtt without reading up on it. It doesn’t support the Sonoff Zigbee Bridge at the moment. See the github for more info >

Do you have one of the Outdoor motion sensors?
Does it have any more features than the indoor model?
Or is it just a more robust battery and case?

It has an IP54 rating, meaning it has no problems with rain. Also has a wider angle, so it can see more top/bottom/left/right and had a better reach (can see further). So it is better, but for indoors overkill and for indoor usage way too big for my taste. The Hue indoor motion is already very big compared to other cheaper sensors.

But there could be some cases where one might use the outdoor sensor indoors. If you have a very big big/long hallway and want to cover more for instance. But in most cases it’s a waste for indoor usage.

I opted for a Hue outdoor motion detector in the garage to capture motion from the garage door, the side door and the house door. The indoor version wouldn’t always pick up motion coming from the garage door