All my issues with SNZB-03, that was stuck/lost in home assistant were over after I replaced shitty USB-zigbee adapter CC2531 with ConBee 2. Since few months my 2 SNZB-03 (one with standard battery and one with 18650) are 100% reliable and range is like 5 times better.
I am steering away from the SNZB-03’s that I have: they didn’t proof to be reliable for me and whatever I tried, I could not get them to work flawlessly.
There are a lot of tips here and it seems that the issues return after some time.
I bought them because of the size primarily and of course being cheap.
Like most of us tinkerers I was curious if it’s possible to make them work.
In my setup with a conbee II, connected with and extension cable and not being far off from these sensors, I still keep getting drop offs.
Now I’m testing Philips Hue sensors: they are bigger and more expensive but you get motion, luminance and temperature detection in 1 device.
Just became an owner of couple of them and they work so freaking randomly that they make my heading and not just causing one issue, every time there’s sth else that make me wanna cry. Now one of them does not want to discover my presence in the room although I freaking jump in front of it. Turn’s the light on perfectly fine, but then after 2 minutes of no movement it should trigger the light to go down aaaand although I’m jumping like a freaking monkey it turns the light off in front of my face!.. And it worked till two days ago just so perfectly fine! Just tried couple of ideas from the thread but still nothing… Well one more lesson to not expect too much from a cheap shit …
I REALLY wonder if anyone has a good experience with these sensors!
Other devices from the same company work very well and have good battery life though.
I have 9 of these sensors in my house, and now all of them are working propperly.
I had mainly two problems with them:
- Falses positives: I workarounded this problem by putting them in pairs, and only when both of them trigger, the alarm triggers (I made a group for this purpose).
- Lost connection with bridge (or false negatives).
I think the problem with these devices is that sometimes and in some devices, battery don’t make good contact with terminals, so when one device had these kind of problems, I opened it and bended a bit terminals to assure battery has good contact with them.
Since then, the problems with sensors are very sparse and I can consider them as reliable.
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Hi All, very interesting thread from some time back.
I noticed that a lot of issues with these Sonoff ZB motion sensors are somehow linked to de (battery) voltage to the device.
Has anyone experimented with solid 4V or 5V power to such motion sensor from a reliable external power supply?
If so, any better performance and reliability of the motion detector?
Interesting!! I’ve done something similar: most of my Sonoff motion sensors run now on 3.25V DC wired from a power adapter.
I wonder if someone here as performance experiences with these motion sensors running on 4, 5 or even higher voltages.
Hi All,
From all the experiences of the many different people with the Sonoff SNZB-03 motion sensor, we know it is really a crappy device falling off the Zigbee network regularly and totally unexpectedly. Even with a solid external power adapter you face those issues.
Most of the time you have to complete repair then the SNZB-03 sensor, which in practice is really crap.
Probably most of us want to completely dump those sensors in the trash…
But, has anyone any idea what the fundamental cause is of the regular ‘drop off the zigbee network’ behavior of these motion sensors? Is it instable firmware by Sonoff? Or are messages wrongly transmitted or received by those SNZB-03 sensors?
I never had issues with these devices falling of my network (conbee2/deconz)
My problem was that it has so ridiculously many false movement registrations, that the device is totally unusable.
I have testet about 5 sensors on my setup and the same sensors on a different setup with a sonoff!! usb dongle and ZHA and getting exactly the same issues.
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Yeah, I think the main/most common problem with the SNZB-03 is false positives which makes them unusable.
Of course falling of the zigbee mesh is not less problematic but seems to happen not that much.
@Marc_Sway (or anyone else): does it make any difference regarding false positives when powered from a USB power adapter?
I’m curious too as to why this happens.
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Power: These Sonoff SNZB-03 sensors run on 1 CR 2450 battery cell, 3 volts. This is already quite bad design since those motion sensors are known to be quite sensitive to generate many false triggers during the day and also at low temperatures (if you use those sensors outside), empty the battery quite quickly. Also, I noticed that when the battery voltage drops below 3V (for instance 2.95V) many of these SNZB-03 simple stop working. So, with these small (1 off) CR 2450 battery cell, easily within 1 week of working, the whole sensor stops property working due to an exhausted battery.
That is also the reason that any other professional PIR motion detector never runs on a single CR 2540 battery cell!
Thus the Sonoff SNZB-03 is badly designed from a power perspective.
For that reason I power those Sonoff motion sensors in and around my house now with wired power, via a 5V Apple USB power adapter and a stepdown converter to 3.3 V. This works much better, but I would even prefer to run on 4 VDC if I could to have some margin in respect to voltage loss over long wires:
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And you don’t have ANY false positives anymore?
I did a quick search on the other home automation platforms to find similar reports about false positives: didn’t find anything yet.
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With the wired powering from a stable power adapter it got a bit better, but what really reduced the number of false triggerings was the shielding of the PIR sensor itself!! That reduced in my case at least the number of false motion triggers with 50% or more.
I use those Sonoff sensors also outside:
And shielded those with some small PVC pipe pieces (glued) + also installed an Alu strip above it against some rain and sunshine influences.
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Another note: since my SNZB-03’s are hard-wired powered, I can power off and on these devices quickly.
I noticed that once a SNZB-03 ‘dropped off the Zigbee network’, switching off and on the power again (I keep usually ca 30 secs in between), this helps to get the SNZB-03 ‘recognised’ again in the Zigbee network.
Does someone by the way know:
If the SNZB-03 is put in pairing mode and it pairs with Sonoff’s ZBBridge, is that pairing then happening via Zigbee or via perhaps Bluetooth?
For me it is unclear why Sonoff always is promoting that during pairing a sensor (like the SNZB-03’s) is very close to the coordinator (like a ZBBridge).
———-
I did some further experiments to understand and reduce the ‘drop of the Zigbee’ issues with the SNZB-03 sensors:
Since those sensors at my set-up are all powered hard-wired with a power adapter, I switch now every night the power off for 2 minutes for all these sensors.
Then after 2 min, all these sensors start repairing to the Zigbee network (I leave always on).
With this daily repairing actively of the motion sensors in the middle of the night. I noticed that totally random ‘dropping off the network’ events dramatically decreased.
What is a good sign!
They don’t have Bluetooth
Because then you have the best connection, and less chance of failure. (And less tech support calls 
).
My overall assessment of the SNZB-03 is that this device is a Not-for-purposed designed PIR motion sensor
It is cheap and small, but that comes with a price: unstable, quite unpredictable and bad performance with many false motion triggers, running quickly out of battery life and totally random falling of the Zigbee network events.
I have 2 in use outdoors (under cover of course)
- Not sure what unstable or unpredictable mean (I had no problem pairing them)
- Yes - there have been occasional false triggers but not “many”
- Battery life is fine for me. Mine have been going for 2 years but not high traffic areas.
- They go beyond my 3 hour presence reporting limit every now and then but have never fallen off the network completely.