I’m always pleased when ITEAD releases new Sonoff products that use ZigBee to speak to other devices. Why? They are well priced and easy to integrate with the eWeLink app as well as with DIY automation servers. The two latest products are temperature probes that bring not just ZiggBee but LCD screens and external probes: SNZB-02WD & SNZB-02LD
Let’s check it out.
Sonoff SNZB-02WD & Sonoff SNZB-02LD
After the release of the Sonoff SNZB-02D – a ZigBee 3.0 indoor temperature and humidity sensor with an LCD and the smart water valve Sonoff SWV, I expected them to release something specifically for outdoors. ITEAD didn’t disappoint and brought IP65-rated sensors for outdoors.
They come in two flavours:
Sonoff SNZB-02WD
Sporting 2 year battery life and costing $17.99, this ZigBee 3.0 sensor brings a large and easy-to-read LCD display that shows the current temperature and humidity (supports metric and imperial units). It’s powered by a think CR2477 (AmazonUK|AmazonUS) battery and offers very frequent updates – every 5 sec.
The sensor comfortably measures the temperature between -20°C and 60°C with 0.2°C accuracy.
Sonoff SNZB-02LD
Just like the WD version, this sensor costs $17.99 and brings a large and easy-to-read LCD display that shows the current temperature (supports metric and imperial units). It’s powered by a think CR2477 (AmazonUK|AmazonUS) battery and offers very frequent updates – every 5 sec.
What sets this sensor apart is the attached permanent probe on a 1.5m long cable. Thanks to the external probe, Sonoff SNZB-02LD can measure temperatures between -40°C and 115°C. You’ll also notice that the sensor lacks the humidity values as it only uses external probe to moniotr whatever you dunk the probe into.
It’s a shame that SNZB-02LD doesn’t support internal as well as external temperature, as it would be handy to see the difference between these two.
eWeLink use
If you own an eWeLink compatible ZigBee hub like:
- Sonoff iHost, (review)
- Sonoff NSPanel Pro, (review)
- Sonoff Bridge U, (review)
- Sonoff Bridge Pro,(review)
You’ll be able to quickly pair it and use it for your home automation. Considering the weather-proofing, display and external probes, these would be great for monitoring weather, water temperature and environmental conditions inside saunas or greenhouses.
As an added advantage, the eWeLink app will display current and historical data from the sensors for up to 6 months. Unfortunately, the reports give the temperature recorded in hour intervals – it’s good for the weather or slow changes over time. Still, it will fail to record frequent fluctuations in eWeLink.
Since the temp probs aren’t fun on their own, I decided to see what would happen if I drop the 02LD into my kettle and let it boil. Not the whole sensor, but the probe! I will also show you why there are memes about separate taps in the UK. And how close to the truth they are!
Turns out my kettle boils to 99.5°C within minutes, and the hot water in the tap runs at almost 55°C. It’s officially confirmed that split taps are hot/cold and unpleasant. But the biggest takeaway from that is that neither of the temperature tests was logged in the eWeLink history… only in the current feed from the sensor.
I guess, I have to do it myself!
Trying Sonoff SNZB-02WD & Sonoff SNZB-02LD with ZigBee2MQTT
Since I cannot have a detailed chart of temperature changes in eWeLink, let’s bodge something real quick in NodeRED and see how well this would work. I suspect that SNZB-02WD & SNZB-02LD will be supported by ZigBee2MQTT (if not I can use the converter from SNZB-02D).
You can use a couple of ZigBee coordinatorsto make it happen! I covered in the past:
- Sonoff USB dongle
- SM-Light Coordinators
- Others..
There was no issues pairing these sensors in ZigBee2MQTT but as I have been sent them early, there are no converters yet. Not a big issue as the SNZB-02D is already suppored. By the time you get your probes, SNZB-02WD & SNZB-02LD will be added.
In case you want to make it work for now, find sonoff.js in your devices folder of zigbee2mqq and add your model numbers:
zigbeeModel: ['SNZB-02D','SNZB-02LD','SNZB-02WD'],
model: 'SNZB-02D',
vendor: 'SONOFF',
description: 'Temperature and humidity sensor with screen',Between this and a simple chart node in NodeRED, it took moments to get my temperatures and humidity onto a dashboard. While this works for visual data, if you want your data saved, consider a Grafana and Influxdb database to store and display the data more permanently.
It’s easy and simple and the payload from sensors look like this:
{"battery":100,"humidity":59.8,"linkquality":145,"temperature":20.5}Just bear in mind that the SNZB-02LD (the one with the external probe) does not report the humidity.
Final Thoughts
Both Sonoff SNZB-02WD & SNZB-02LD sensors are great and can be added to your home automation in more than one way. While you can trigger automation in eWeLink based on various temperature levels, you won’t see it in the history. Thankfully, adding ZigBee2MQTT is very easy, and now you know how you can retain a much better history of your readings. Let me know if you’re going to get these in this Reddit thread.
🆓📈 – See the transparency note for details.
