Which battery-powered PIR sensor for Home Assistant? SNZB-03 commissioning and interior

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Post #1
21405264 22 Jan 2025 20:15

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The Sonoff SNZB-03 is a tiny (only 40x35x28mm) PIR sensor that is compatible with Home Assistant via, among other things, Zigbee2MQTT. It is available to buy for around £40-50, depending on whether you order from China or our country. It is powered by a tiny CR2450 (3V) battery. Properly configured, it is capable of triggering various automations, such as turning on a light when movement is detected.
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In addition to the sensor, we get a strip of 3M double-sided tape for mounting. There is also an instruction manual:
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However, I will skip the pairing with the manufacturer's gateway and give it a go with HA straight away.
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Pairing with Home Assistant Pairing with Home Assistant.
I have Home Assistant set up according to a theme from a few years ago, but obviously updated:
Home Assistant tutorial - setup, WiFi, MQTT, Zigbee, Tasmota .
Zigbee2MQTT I also updated:
How do I update Zigbee2MQTT Home Assistant to the latest version? Unsupported device? .
If you need to, reset the device as instructed, at HA make sure pairing is enabled.
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The sensor should appear in our panel:
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The sensor provides an 'occupancy' status, i.e. detection of movement, which is cleared after 60 seconds. In addition to this, we have the battery status (by percentage, there is a separate low battery warning), tamper and connection quality. The tamper, in turn, determines whether someone has taken down the sensor and its implementation depends on the device.
A PIR paired in this way can already trigger events:
Home Assistant - how to trigger an event with a PIR sensor? Zigbee and WiFi, lighting up Home Assistant - how to trigger an event with a PIR sensor.

Interior of SNZB-03 .
For educational purposes only. We take a look inside:
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The sensor is based on the CC2530, as are brother products including the SNZB-04 (door/window opening sensor).
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The CC2530 is a Zigbee 2.6 compliant SoC solution offering 256kB of Flash memory, 8kB of RAM and 21 GPIOs, including a 12-bit, 8-channel ADC, 2 SPI/UART and 4 timers.

Summary .
Seamless pairing, you can go straight to scripting the automation. I guess the only thing to keep in mind is that this sensor doesn't extend the range of our Zigbee network as it is a battery powered device, but that shouldn't cause us any problems.
I have already shown an example of an automation done based on this sensor:
Home Assistant - how to trigger an event with a PIR sensor? Zigbee and WiFi, lighting up .
For my part, that's it. And what PIR-based automations would you guys create? .

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#2 21405427 22 Jan 2025 21:51

@GUTEK@ @GUTEK@

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Post #2
21405427 22 Jan 2025 21:51

I recently bought such a sensor in china https://www.zigbee2mqtt.io/devices/ZP01.html
Basically works the same as the one described by the author of the topic, only that it is powered by 2xAAA. Which are, however, more easily available, and everyone has one at home.
It provides the same entities, i.e. charge level, low battery level, detection (Occupancy) and violation (Tamper). Except that there is no switch from violation, so it's a dummy.
When motion is detected it holds the status for about 40s, then if no one is present it goes back to no detection.

I have this problem though, I don't know if it's the fault of this sensor or the hub I'm using, but there are times when a status change won't be picked up by the Z2M. It is sporadic, but I connected a Christmas tree light for Christmas under the automation with this sensor and it happened that despite motion detection (the LED flashed) the status did not change, the same in the other way, the sensor was able to not send a non-detection.

Overall a cool toy, especially when integrated with HA. The big plus of the Zigbee version is the instantaneous status transmission. Where the same WiFi version of the sensor, apart from the higher power consumption has some 6s delay until it connects to the network.
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#3 21405668 23 Jan 2025 02:21

jarekgol jarekgol

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Post #3
21405668 23 Jan 2025 02:21

How long does something like this run on batteries? Assuming it's indoors and for 16h is triggered several times for each hour?
#4 21406377 23 Jan 2025 15:41

krzbor krzbor

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Post #4
21406377 23 Jan 2025 15:41

In the screenshot I see that the "Friendly names" are not particularly friendly. This happens when a new device is connected. If HA is running at the moment, it unfortunately takes on these bizarre meanings. To change this you need to:
1. set the "Friendly name" correctly in Z2M
2. in HA remove this device (it is as a device in MQTT).
3. reboot the Z2M (the reboot option is available from the browser).
After the restart, Z2M will register our device again with the name we set.
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#5 21406493 23 Jan 2025 17:30

CMS CMS

Administrator of HydePark

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Post #5
21406493 23 Jan 2025 17:30

Quite large and expensive. I prefer such 33x27mm https://pl.aliexpress.com/item/10050081588407..._id=202501230824352596395740709020006331535_4

Powered by a Cr2450 battery, the Chinese one claims a life of 1.5 years with 10 triggers per day. At my place it has been working in the kitchen since November 2022. It is active from dusk to dawn, and making a dozen triggers a day. At the moment, the battery has 1%

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#6 21406527 23 Jan 2025 17:43

p.kaczmarek2 p.kaczmarek2

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Post #6
21406527 23 Jan 2025 17:43

@krzbor I don't know if we are talking about the same thing, but isn't it enough in Zigbee2MQTT in HA to click rename?
I have had a device with an unchanged name for a few days now. I now follow these steps:

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Immediately afterwards I have:
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I have not rebooted anything.

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#7 21406851 23 Jan 2025 20:45

Nargo Nargo

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Post #7
21406851 23 Jan 2025 20:45

I purchased 2pc in October https://pl.aliexpress.com/item/10050061579144...tem.3.744e43ceoVsp1b&gatewayAdapt=glo2pol for £12.80 each

They expose:

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The simplest automation to switch on a light bulb from IKEA in the pantry.
#8 21406978 23 Jan 2025 21:51

@GUTEK@ @GUTEK@

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Post #8
21406978 23 Jan 2025 21:51

krzbor wrote:
In the screenshot I can see that the "Friendly names" are not particularly friendly. This happens when connecting a new device. If HA is running at the moment, it unfortunately takes on these bizarre meanings. To change this you need to:
1. set the "Friendly name" correctly in Z2M
2. in HA remove this device (it is as a device in MQTT).
3. reboot the Z2M (the reboot option is available from the browser).
After the restart, Z2M will re-register our device with the name we set.
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At the bottom you click on the icon to change the device name. In addition, you tick "Update Home Assistants entity ID" and that's it. You don't have to do anything extra, you don't have to restart anything. The name changes in both Z2M and HA.
#9 21407519 24 Jan 2025 11:45

krzbor krzbor

Level 27

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Post #9
21407519 24 Jan 2025 11:45

@GUTEK@ wrote:
Additionally, you tick "Update Home Assistant entity ID" and that's it.
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Was this option in the older Z2M? I have it now, but don't know if it was before. Renaming changed the name in HA, but the entities had the old numeric identifiers. I'll be pairing something up soon and see if it works that way.
#10 21407626 24 Jan 2025 13:04

@GUTEK@ @GUTEK@

Level 31

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Post #10
21407626 24 Jan 2025 13:04

I started using from version 1.42, now I have 2.0. And in these versions it was, as before I don't know.
#11 21411772 26 Jan 2025 23:06

Michal8883 Michal8883

Level 5

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Post #11
21411772 26 Jan 2025 23:06

What is the best way to connect zigbee sensors? Via a dongle to a raspberry zero2w or just a gateway and an app e.g. HA?
#12 21412557 27 Jan 2025 16:06

gsm_42 gsm_42

Level 11

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Post #12
21412557 27 Jan 2025 16:06

Ikea has also recently added a PIR sensor on Zigbee. In my opinion, with 2x AAA power supply, they will definitely last longer than the Chinese Sonoff fakes.
https://www.ikea.com/us/en/p/vallhorn-wireless-motion-sensor-smart-white-40504348/
#13 21412932 27 Jan 2025 20:02

@GUTEK@ @GUTEK@

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Post #13
21412932 27 Jan 2025 20:02

Michal8883 wrote:
How best to connect the zigbee sensors? Via dongle to raspberry zero2w or just a gateway and application e.g. HA?
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If you want under HA it is best via a dongle e.g. from Sonoff. Gateways are usually under cloud systems e.g. Tuya, eWelink. Some can be reprogrammed and used with HA.

gsm_42 wrote:
Ikea has also recently added a PIR sensor on Zigbee. In my opinion, with 2x AAA power supply, they will definitely last longer than the Chinese Sonoff fakes.
https://www.ikea.com/us/en/p/vallhorn-wireless-motion-sensor-smart-white-40504348/
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These sensors are plentiful. I have now bought one with a radar function out of curiosity. I will just be testing it out.

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Topic summary

The discussion centers around the Sonoff SNZB-03 PIR sensor, which is compatible with Home Assistant via Zigbee2MQTT. Users share experiences regarding its performance, battery life, and setup. The SNZB-03 is compact, powered by a CR2450 battery, and can trigger automations like lighting upon motion detection. Alternatives, such as a sensor powered by 2xAAA batteries, are mentioned for their availability and similar functionality. Users also discuss issues with device naming in Home Assistant and the ease of connecting Zigbee sensors through various methods, including dongles and gateways. The IKEA Vallhorn PIR sensor is noted as a viable alternative with potentially longer battery life.
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FAQ

TL;DR: Real-world use shows 26 months battery life at ~12 triggers/day [Elektroda, CMS, post #21406493]; “pairing takes under a minute” [Elektroda, p.kaczmarek2, post #21405264] CR2450- or 2×AAA-powered Zigbee PIRs link directly to Home Assistant through Zigbee2MQTT, exposing motion, battery and tamper states. Why it matters: picking the right sensor and power cell avoids false alarms and mid-winter battery swaps.

Quick Facts

• Size: 40 × 35 × 28 mm (SNZB-03) [Elektroda, p.kaczmarek2, post #21405264]
• Power: CR2450 coin cell or 2 × AAA, 3 V nominal [Elektroda, @GUTEK@, post #21405427]
• Hold time: 40–60 s before “clear” state [Elektroda, p.kaczmarek2, post #21405264]
• Claimed battery life: 1.5 years at 10 triggers/day [Elektroda, CMS, post #21406493]
• Street price: £12–£50 depending on brand and region [Elektroda, multiple posts]

Which Zigbee PIR models are most discussed in the thread?

Sonoff SNZB-03, Tuya ZP01, several 33 × 27 mm no-name sensors, and IKEA VALLHORN are compared for size, battery type and cost [Elektroda, #21405264; #21405427; #21406493; #21412557].

How do I pair the Sonoff SNZB-03 with Home Assistant?

1) Enable pairing in Zigbee2MQTT. 2) Press the sensor’s reset button until the LED blinks. 3) Wait for the device card to appear in HA. The whole process takes <60 s [Elektroda, p.kaczmarek2, post #21405264]

What entities does a typical Zigbee PIR expose?

Occupancy (motion), battery percentage, low-battery warning, link quality, and tamper. Some models list tamper but never toggle, making it a dummy entity [Elektroda, @GUTEK@, post #21405427]

How long do the batteries really last?

A CR2450 lasted 26 months in kitchen duty before dropping to 1 % [Elektroda, CMS, post #21406493] Zigbee2MQTT docs cite 12–18 months typical for 10 daily triggers (ZP01 page). AAA models usually exceed two years because of higher capacity [Elektroda, 21405427]

Does a battery-powered PIR extend the Zigbee mesh?

No. End-devices sleep to save energy and cannot route traffic. Place mains-powered repeaters to strengthen coverage instead [Elektroda, p.kaczmarek2, post #21405264]

How can I rename an awkward entity ID in Home Assistant?

Click the pencil icon in Zigbee2MQTT, set a Friendly Name, tick “Update Home Assistant entity ID,” then save. No restart needed in versions ≥1.42 [Elektroda, @GUTEK@, post #21406978]

What if motion events are sometimes missed?

Sporadic misses often trace to weak link quality; add a repeater or move the PIR closer to the coordinator. Firmware bugs can also drop packets; update Zigbee2MQTT and sensor firmware when available [Elektroda, @GUTEK@, post #21405427]

Dongle or branded gateway—what integrates best with HA?

A USB coordinator (e.g., Sonoff ZBDongle-E) gives full local control and works offline. Most cloud gateways lock you to proprietary apps unless you flash them, which voids warranty [Elektroda, @GUTEK@, post #21412932]

How fast is a Zigbee PIR compared with Wi-Fi?

Zigbee triggers are near-instant (<1 s), while Wi-Fi sensors can add ~6 s due to network association [Elektroda, @GUTEK@, post #21405427]

What chip powers the SNZB-03, and why care?

It uses a Texas Instruments CC2530, a Zigbee 2.6 SoC with 256 kB flash and 21 GPIOs [Elektroda, p.kaczmarek2, post #21405264] Hackers can reflash it for custom firmware, extending range or adding features.

Are smaller or cheaper options available?

Yes. 33 × 27 mm PIR modules start at ~£22 on AliExpress and pair like the Sonoff units [Elektroda, CMS, post #21406493] IKEA’s VALLHORN costs ~US$15 and runs on AAA cells [Elektroda, gsm_42, post #21412557]

Can radar presence sensors replace PIR?

24 GHz radar modules detect micro-movement and work through thin materials, but draw more current and require USB power. One user is testing a $20 radar-based Zigbee sensor now [Elektroda, @GUTEK@, post #21412932]

Quick 3-step automation example: turn on pantry light

1) In HA Automations, choose the PIR’s Occupancy = “on” as trigger. 2) Add action: turn on desired Zigbee bulb. 3) Add second action: delay 40 s, then turn off bulb. Works because the PIR clears after 40–60 s [Elektroda, multiple posts].

Why does the tamper entity never change state?

Some low-cost sensors label a GPIO as tamper but leave the pad unconnected, so the firmware always reports “clear.” Treat it as a non-functional placeholder [Elektroda, @GUTEK@, post #21405427]

Expert tip for battery savings?

“Mount the PIR above shoulder height; fewer triggers equal months more battery life,” advises user CMS [Elektroda, 21406493]

Which battery-powered PIR sensor for Home Assistant? SNZB-03 commissioning and interior

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Topic summary