Ikea selle rechargable ones for really cheap additionally.
I never knew Ikea had temperature sensors, might replace my current ones with Ikea even if they don't use Zigbee. AAA batteries are great!
Sometimes they either stop updating or drop off the network permanently.
I wouldn't really trust them for anything even remotely important.
Shame since they're pretty cheap, perhaps they'll fix the firmware and then they'll be excellent.
They have a more expensive variant looks more like desk alarm clock, that also measures particulates and carbon dioxide (and tells time), and that one can stay always-on (and act as Thread router) - but they wisely remembered to add remotely triggerable switch to switch the display off, too.
¹ https://www.ikea.com/ca/en/p/alpstuga-air-quality-sensor-sma...
² https://www.digikey.ca/en/products/detail/sensirion-ag/SEN63...
https://community.home-assistant.io/t/ikea-kajplats-smart-bu...
I have a lot of qualms with Threads, such as Thread device internet access through TBRs that do not allow you to disable NAT64 (or even worse, getting globally routable IPv6 addresses in Thread 1.4), but complaining that people have to buy another device is not one.
People are far more likely to have a TBR already than an IKEA Zigbee Hub. And even if they hadn't, they could get any other TBR/Matter Server besides IKEAs. So it's not a great way of selling smart home hubs.
[1] https://appleinsider.com/articles/24/09/18/apple-enables-dir...
Like, IKEA's Zigbee water leak sensor (BADRING?) with 2 AAAs (1.2V; they don't like 1.5V) has a battery life of 9-12 months. My Aqara water leak sensors (CR2032) have been going strong for at least 3 years. They predate me starting to track it with Battery Notes and that has to be 3 years ago (and yeah I test their functionality every 6 months or so).
https://community.home-assistant.io/t/ikea-kajplats-smart-bu...
via
https://www.reddit.com/r/homeassistant/comments/1tvtyyj/ikea...
It's also been interesting to see when placing hot food in the fridge how long the temperature stays elevated for. I put the sensor in a ziplock bag and sucked the air out of it so it has weatherproofing.
Recommend this exercise to everyone.
Works great.
Being able to see the fridge temp to a tenth of a degree and getting alerted when it’s wrong has been much more useful than I expected. The safe fridge temp is a fairly narrow band that’s basically impossible to hit without a proper temp sensor.
Once out of battery, replacing the battery means you need to re-pair them to the network since they don't rejoin automatically. Thankfully Home Assistant sees it as the same device, but it has been a pain, and the batteries get expensive really quickly.
I've been slowly replacing them with Ikea's Matter sensors instead, they have a display that comes on when you tap them, and join the rest of my Thread network. Slowly over time I am likely to replace all of my Zigbee based devices with Matter/Thread based devices because it seems to be far more stable for my use cases than most of my Zigbee devices, especially battery powered ones seem to last much longer when using the Matter/Thread based versions.
They're really annoying to pair though, so I've replaced most of them with Sonoff SNZB-02P which runs a CR2477 battery and I expect the battery life to be at least 3 years; with some luck maybe 4? Not as slim however, but the built-in magnet makes up for it.
What's your experience with Matter / Thread? Is it a case of buying a different USB dongle and devices?
I've tried a couple of times but just gave up because zigbee/zwave work well enough and I'm not sure I'll like where thread/matter end up in a decade.
I have a couple of the Tuya ones and I'm pleased with them. The humidity accuracy is questionable, but it's fine.
I also have an airgradient (not zigbee, uses wifi) for high accuracy the one place I care about that. Works great in Home Assistant with esphome.
Aqara sensors use zigbee, but NOT the full protocol, like Ikea ones for example. So they work fine, until they lose a connection to a router. Zigbee protocol dictates that it will need to try connecting to another router, but aqara does not.
I have a lot of these sensors in my home, normally the connection is fine (5+ years) but sometimes I lose one. Because somebody turned off the lamp (ikea one, acting as a router) (by cutting the electricity to it) by mistake. Then, the connection is lost to that router and it will not try to reconnect.
When the router does not switch, the connection stays. I don't even need to re-pair when changing the batteries!
I've read this somewhere, take it with a grain of salt and validate it yourself if possible.
Aqara might be the ones with a crappy ZigBee implementation that doesn't roam right so if you move them or your topology changes, they'll drop off.
I'm 2 years in, I think, and I have never noticed any issues.
Half of people seem to swear by them, and half hate them. They did seem great until I kept having to reconnect them every couple days, so I get why the lucky ones are happy.
I have several E1 wired switches and had to resort to replacing the firmware on them[0]. They don't drop off the network as their sleepy end devices tend to, but they also can't be bound to other devices.
[0] https://www.ducktoast.com/blog/electronics-projects/aqara-e1...
+1, complete waste of time and money. I thought my Zigbee network or HA was the problem, but the sensors are just garbage.
My Zigbee sensors are these Aqaras, and the initial pairing has worked just fine.
They worked fine with the ConBee 2, and work fine with the ZBT-1 that replaced it.
That said, they're used within a relatively small area, and have direct connection to the coordinator. My one (major) annoyance with them is how hard it is to open the battery compartment, the plastic is too soft.
I've since added some Sonoff T+H sensors which are fine, though twice as big.
My one disappointment is the Arre (Thread) sensor, which has low resolution and bad battery life.
Also, I don't know if anyone saw but there's a giant list of amazon prime discounts on there rn: https://smarthomescene.com/news/best-smart-home-deals-for-am...
I do not have any Zigbee devices but I have many Hue devices. Their connectivity is shit. Button presses are not being registered. Sometimes commands do not reach devices etc. That's why I tried to avoid Zigbee.
But the low power battery operated zigbee stuff are pretty attractive if things work fine.
https://www.oscium.com/training/zigbee-wifi-coexistence/
Deploying 2.4GHz Wifi, Zigbee, and Thread near each other requires some planning + corresponding configuration. A lot of Zigbee hubs try to find a quiet channel during the initial setup, but it does not always work.
How does Zigbee compare to Matter?
Matter over Thread is the most comparable to Zigbee (there is also Matter over WiFi). It's vastly more complex, since it uses IPv6 (ULE), mDNS, non-radio links between TBRs, provisioning is typically done through a smartphone with Bluetooth LE [1] etc. But it's also more standardized in that Matter defines the device types, so in principle a device will work with any Matter server, whereas with Zigbee support generally needs to be added per device (though there are generic drivers as well).
Big tech and IoT companies love Matter, because they can eventually gather analytics from devices or require cloud subscriptions. This is not just the case with Matter over WiFi, but Matter over Thread already allows devices to use NAT64 to connect to IPv4 servers on the internet (and TBRs like Apple TV do not allow you to disable NAT64). Thread 1.4 also allows for Thread devices to get globally routable IPv6 addresses. The Thread 1.4 white paper does not even try to hide what this could be used for:
Thread devices can now seamlessly connect directly to cloud services, enabling remote control, monitoring, and over-the-air firmware updates.
https://www.threadgroup.org/Portals/0/Documents/Thread_1.4_F...
So, yeah, Matter + Thread does some things better, some things worse, and opens up new avenues for monetization that were not possible with Zigbee, because Zigbee devices were fully local and owned.
[1] There are workarounds, e.g. Home Assistant allows provisioning through Bluetooth proxies. Also, provisioning does not currently work on alternative ROMs like GrapheneOS.
My friend has problems with zigbee and has moved to matter and is now trouble free. The only fine zigbee stuff for him was the Hue lights though.
CO2 and equivalents on the other hand is Wild West.
It's the most first world of first world problems, but purely for that reason any more I buy will be Sonoff.
I've had Tuya and Aqara sensors outside, undercover and out of direct rain for the past 3 years, and every one lasts about a year before the humidity sensor gets stuck at the maximum reading. Even bringing it indoors doesn't get it working again. I'm hoping the built-in heater on the SHT45 will help when we're sat in sea mist or sea fog and keep the sensor working for longer.
> It is worth clarifying from the start that my setup does not represent typical room comfort conditions, since the calibration was done at a much lower temperature, around 4°C. Sensors do not always respond in a perfectly straight line across a wide temperature range, so this fixed point is not a guarantee of the exact same accuracy at room temperature.
This can be fixed pretty easily if you are up to a little simple DIY.
Instead of using the MHO-C401, calibrated at one point against a lab-certified thermometer, build on a solderless breadboard your own temperature/humidity sensor using an ESP32 or ESP8266 dev board and a Sensiron SHT45 temperature/humidity sensor and program it using Arduino.
The SHT45 communicates with the ESP over I2C. The wiring is simple: ESP 3.3V, GND, SDA, SCL to SHT45 VCC, GND, SDA, SCL, in that order. Just 4 wires. The ESP dev board will be powered by USB. (If you need it to be battery powered, just use a small USB power bank).
The SHT45 has an accuracy of ±1% RH and ±0.1℃ out of the box.
If you want even better temperature accuracy add a tmp119 temperature sensor. This too uses I2C so the hookup is the same as the SHT45 hookup. It has a temperature accuracy of ±0.08℃ max and it typically is ±0.03℃ and is NIST-traceable out of the box. This is across a range of 0℃ to 45℃. (Outside that range it is ±0.2℃ from -55℃ to 150℃).
Adafruit has all the sensors [1][2]. Those have JST connectors using a standard pinout for daisy chaining I2C devices, which would be good for this application so when measuring temperature in the fridge or freeze you don't have to put the whole breadboard assembly in there. They have cables up to 400mm long [3].
You know what...you don't even actually need the breadboard! Here's a JST to female socket cable [4] that could connect one of the sensors to the pins on the ESP dev board.
ESP, that cable to the sensor, and if using two sensors, the sensors daisy chained with JST to JST cable.
Adafruit has ESPs also, but they seem to be out of stock on most of them. There are plenty of suitable ones on Amazon that are pretty inexpensive.
I'd say go for an ESP32 C5 or C6. They both support 2.4 GHz wifi and Zigbee, so your have the choice of reporting reading to a web server or making your DIY reference temp/humidity sensor use Zigbee. The Arduino library from ESP includes built in classes to make making Zigbee sensors easy.
Oh, they also support Matter over wifi, so you could make this a Matter device.
The C5 adds 5 GHz wifi.
Just remember that an ESP32 generates enough heat due to the radio that these sensors will pick it up if the are too close. If you build on a breadboard don't be the sensors right next to the ESP.
This is a fairly reasonable first project if you've not done any MCU stuff before but do have programming experience, especially nowadays with LLMs. They seem to have a pretty good grasp of Arduino stuff. (Don't just vibe code it! Just use them when you get stuck on something or want some documentation clarified or things like that. That will be a lot more interesting).
[1] https://www.adafruit.com/product/5665
[2] https://www.adafruit.com/product/6482
I'm looking right now at something like what I describe that I built 10 years ago, except the sensor is much less accurate (±1.0℃), the ESP8266 module I used didn't have USB so it is powered by an MB102 breadboard power supply, and I used NodeMCU.
On the breadboard there is the ESP8266 module [1], the sensor breakout (a BMP280, which uses I2C just like the newer much more accurate sensors), the MB102, and 6 wires. 2 wires are connecting the ESP2866 module the power and ground, 2 wires connecting the BMP280 to power and ground, and 2 wires connecting the BMP280 to the ESP8266.
If I had used an LLM it probably would have not left out the important thing that I completely overlooked: the SDA and SCL lines for I2C need pull-up resistors. Many sensor breakout modules include them, such as the BMP280 modules in my 10 year old project, so I forgot about them.
HA uses the external sensor readings to set an external measured value for the radiator thermostats.
Works fine for me but I guess you might run into problems in a more exposed "watery" place (London doesn't really have extreme rain or humidity.)
[0] Like this https://www.amazon.co.uk/Technoline-TXCOVER-White/dp/B08DKZD...
I ended up with some Ecowitt (hardware sold under the Ambient Weather brand in the US) sensors and they’ve been working great for some months now. (900mhz RF has good penetration and the sensor hardware is generally appropriate for -20C operation.)
The best sensor in my tests was CentraLite 3310-G. It was the only one actually precise to 1% of RH and 0.1C They are also pretty robust and long-lasting.
Smart light bulbs, for whatever reason I couldn't get them to work with my Apple Home setup, despite trying few different brands.
Smart power sockets, kind of work, but they're big, bulky and have this natural design flaw where when anyone unknowingly or out of habit use the lamp's switch, they stop working, not to mention how useless they are when the wall socket is behind some obstacle, furniture, etc.
Smart radiator controllers that are super noisy in operation and impossible to calibrate, so they constantly report inaccurate temperatures.
Smart home security systems that keep raising false alarms because a cat, a leaf, a bee, a spider or just because.
IKEA smart temperature and humidity sensors (the latest ones) that pair with my Apple Home network for few days and they all just stop reporting data, until a hard reset and re-pairing.
I'm done for anything "smart" for at least few years, they're all a horrible annoyance.
This stuff is still so user unfriendly.
Why cannot the software just save the desired setting to set it when the device comes online next? I feel like many things in zigbee2mqtt are like that: I click something, it fires off some message and it often isn't clear if that worked, if it'll work later, and so on.
I used to work on zigbee network embedded firmware, i wouldn't put that in my home if you paid me.
In short, if you need less than a couple degrees of accuracy, it's going to take a bit of tinkering. I wouldn't trust a $1 sensor for a tropical fish tank, for example, but probably good enough for a home thermostat.
They claim accuracy of +-0.2 c across a wide temperature range and in my use they seem to be. easy to find on a support board for under $10
For power consumption a system power tree needs to be constructed and that will set the bounds that firmware can achieve. That would be better than trusting the manufacturer but a real test is best.
Avg buyer wont read a token of tests before buying whats marketed best.the whole point in test like these is to provide non-average buyer with info average buyer doesnt care for.
Similar reasons: the intended audience isn’t the average person.
You can certainly wreck connectivity with bad and old firmware. Similarly, housing design, PCB thermal isolation, not putting the sensor next to the MCU, measurement averaging settings, etc. all are going to affect accuracy even with the same sensor (particularly dynamic accuracy).
Those who care about the internals are techies who maybe want to build their own or are very curious. Most buyers don't care about that, they care about how well it works in practice. Just like they don't care what RAM chips are used in their phone or computer, what modem, what screen panel, what camera sensor, etc.
I have a bucket of devices which don’t do what I hoped they’d do because they were different from what the reviews said. And not just IoT unfortunately. Some do a better job at flagging these changes, some don’t.
But in the end taking the common case that the product is what it says on the box or that the changes have no impact on how it works, most people don’t care about the name of the chips. Not unless they are very keen on the tech and then there are more tech-oriented niche sites that might provide this.