IoT is essentially a catch-all marketing term, like “organic”, and if I’m not mistaken, the “I” in IoT stands for “internet”. ZigBee devices cannot connect to the internet. Doing so requires a hub or coordinator that contains WiFi or ethernet connectivity. There are many ZigBee coordinators that lack this functionality, which allows your data to stay local, on your own network, without exposing it to the internet.
I never claimed that a smart plug could monitor the temperature inside a fridge, but there are certainly ZigBee temperature devices you could put inside your fridge to do that, and they would work just fine.
A ZigBee smart plug with energy monitoring would certainly give you enough information to determine if the compressor had failed, as the compressor is the component that uses the most power. If the energy usage of the fridge dropped significantly, it could indicate a compressor failure. While this method isn’t foolproof and won’t detect all possible fridge issues, it can serve as an early warning system for major problems like compressor failure.
Refrigerators are damn near Faraday cages. Zigbee devices are going to have a hard time getting their 2.4ghz signaling out.
A failed compressor doesn’t necessatily use less power. If it’s simply lost pressure and hasn’t seized the motor will still cycle and appear to be working from a power usage perspective.
And if the coordinator doesn’t have network connectivity, how is it ever going to alert me to problems when I’m away?
I get that you’re very afraid of the security implications of iot devices, but none of the ideas you’re proposing are actually solutions to the problems a truly connected device can solve.
I’ve been using a cheap Aqara temp/humidity sensor in my fridge for years. Works fine, as I said. Many others do the same. There’s a lot more plastic in fridges than you might expect.
My ZigBee devices use an ethernet based coordinator which communicates with my Home Assistant install via MQTT. The coordinator software is called Zigbee2MQTT. The coordinator does not send any data anywhere except Home Assistant.
There are many easy ways to keep your data local and private while still allowing notification when you’re away from home. In my case, I pay $65/year to Nabu Casa to access my Home Assistant when I’m not at home.
I use a very similar setup to keep an eye on my mom’s place from 500 miles away, including many sensors and multiple camera feeds, which are also local only with no cloud component. Frigate NVR is installed as a Home Assistant add-on, which runs detection on each camera feed and records clips when a person is detected on any feed and also pops a notification at the same time. If she wants to save a clip, she can download it, otherwise it’ll be deleted after 5 days (configurable).
There are other ways to get access to local data remotely. If you don’t want to pay for Nabu Casa (which funds Home Assistant development), there’s also Tailscale/headscale, ZeroTier, Cloudflare, DuckDNS, reverse proxy, etc.
You could also just have Home Assistant send you an email when an event is triggered, like a rise of 2 degrees in your fridge in an hour, or a drop of 20% in energy usage over 30 minutes.
Or you could just have a notification pop in the Home Assistant app on your phone, which will work remotely with most of the methods I just listed.
EDIT: Didn’t respond to your last paragraph:
I get that you’re very afraid of the security implications of iot devices, but none of the ideas you’re proposing are actually solutions to the problems a truly connected device can solve.
I’m not “very afraid”, I’m simply aware of better alternatives. Why would I risk the security of my network by giving Samsung or GE or LG a backdoor into my network when I can get most of the same information their app can give me by using cheap sensors and Home Assistant?
I’m very familiar with homeassistant, been using it for ~5-6 years. First primarily z-wave but now primarily zigbee with a tiny bit of wifi-backed matter mixed in.
That’s a lot of work to replace the sensors that are built into the fridge. 2 temp sensors for the fridge and freezer separately (I’m still not convinced I wouldn’t have issues with the connection being unreliable), a power clamp (you probably don’t want to use a plug since the relays fail open), 2 door sensors, and a fair bit of automation to get notified, not to mention you’ve now added a maintenance task for all those batteries. Especially when the alternative is to connect it to the internet and you’re done. I do connect my homeassistant install to their cloud service so I can get long term tracking and whatnot but the part I need is done with just the internet connection.
Why would I risk the security of my network by giving Samsung or GE or LG a backdoor into my network
That’s just it, with either client isolation or a dedicated and isolated IoT SSID (nearly all modern home routers have one of these) they’re not actually on your network and can’t communicate with any of your other devices, only the internet. I’ve been building enterprise networks for ~20 years now and this is how it’s handled at that level and should be more than enough for a home network.
I do 100% agree for cameras though, that’s all local or not at all.