Most reliable, small Z-wave motion sensor?

Hi all - I’ve used the Iris Zigbee 3326-L motion sensor with mixed results. Generally it works well but eventually it gets “stuck” on Active, whereby after motion stops Iris Motion Sensor (2nd gen, 3326-L)[quote=“Joe_Battaglia, post:16, topic:108093, full:true”]
What about the Battery reporting issues, This is way past getting old now. I have devices dropping off because the batteries are going dead and there is no way I can tell.

What battery issues have you guys been facing?

I’m running into an issue with ST sending apparently inaccurate battery reports on my CR2. Seems to have started within the past couple of weeks, perhaps coinciding with the latest hub firmware update?

Specifically I have a few motion sensors that use CR2. On fresh batteries they usually last 4-6 months. I saw they were low a couple weeks ago and changed them out with fresh ones. Now just a couple weeks later ST is reporting the battery level is low for these sensors again.

It seems the battery readings are inaccurate now. For instance it says my battery is at 89%, even though it measures 3.10vDC !! In which case it should report that battery is at 100%.

Battery reporting

Reported Battery levels are currently way off for some zigbee devices. SmartThings is aware of this and said it will be fixed in some future update, but not precisely when.


I’m confused by your topic title, though, because your post is all about ZIgbee motion sensors but the topic title is requesting information about Z wave. Do you have a preference? Were you specifically wanting to change to Z wave sensors from the zigbee ones you have been using? You will need to make sure that you have enough Z wave repeaters to support zwave sensors if you are switching to a different protocol as zigbee repeats only zigbee and zwave repeats only zwave.

the zigbee bulb problem

Also, there is a completely separate known issue where having zigbee smart bulbs connected directly to the smartthings hub May cause messages from zigbee sensors to get lost, making it look like the sensors have gone bad when actually the problem is the bulb not operating to spec. This does not affect zwave sensors. And zigbee bulbs connected to a hue bridge don’t cause the problem. But there are multiple zigbee smart bulb brands which win connected directly to the smartthings hub do lose messages from time to time. This includes Sylvania/Osram, IKEA, and Ecosmart. Cree seems to have less of the problem. Sengled doesn’t have a problem at all because its Bulbs do not repeat. So I just mention all of this in case you have been adding zigbee smart bulbs to your hub overtime.

Note: SYLVANIA bulbs have a known firmware issue that can occasionally cause them to fail as ZigBee repeaters. This can potentially cause other ZigBee devices to fail to update and/or respond.

back to the topic title

OK, back to the topic title. :sunglasses:

Zigbee is somewhat better than zwave at power management, which allows their sensors to be both smaller and somewhat more responsive than typical Z wave devices in the same price range. This is one reason that the Lowe’s iris motion sensor was so popular in the community – – it was demonstrably faster than, say, the comparably priced go control Z wave sensor. Making the iris sensor more suitable for lighting applications where you want the light to come on when someone walks into the room.

To get comparable speed and size from a zwave sensor, you need to move up in price and quality of engineering, as well as go with a Z wave plus device.

So your two main choices are going to be the aeotec multisensor six or the Fibaro, with the Fibaro generally being slightly more responsive and a little smaller.

But both of these are going to be significantly more expensive than similarly sized zigbee options.

there are several other models with other features as well, so it really does depend on what you’re looking for specifically.

@rboy did a comparison among Z wave models a while back, he might have more to add.

And @krlaframboise recently did an extensive comparison of six different zwave motion sensors in a blog article for The Smartest House which is definitely worth reading:


As far as the battery not reporting 100 percent, that’s typical even when battery reporting is working:

@JDRoberts has summarized it beautifully in terms of ZigBee vs z wave.

The question is what is it you’re looking for from a motion sensor. You can have battery life, additional sensors, response time and price.

You can’t have them all, but if you prioritize them you can have most of them. Thinking about your use case helps narrow down your priorities. Do you need to use the sensor to turn on a light when you enter the room in which response time is critical. Where as using it a security device or presence detection for managing the thermostat you could manage with a slower sensor. Do you need temperature sensor in addition to motion sensor? How about humidity or light? What about a pet detection mechanism to avoid false alerts if you have a pet?

Here is a simple comparison that was done to highlight the above:

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