Looking for a sensor to keep in our freezer. We have 3 instances now where the door has been left partially open and we have almost lost everything. I have tried a door contact but they are not sensitive enough when the door is close to being closed.
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I use iris v2's in ours and it seems to work well. That said maybe a shelly with a probe wire on it?
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After investigating this issue extensively I have two recommendations:
- Visonic MCT-370 (please note the model number, not the more common 350). This is a long range Zigbee device that will transmit thru a solid steel door, and will not "freeze up". Still going strong after 6 weeks in a commercial walk in freezer. Not sure yet how long the built in CR2 will last.
- Minostan MSE30Z: This is a Zwave 700 series device (use the community driver). The real advantage here is that it is rated to -25 degrees C. Uses a 3450 battery, also not sure how long it will last, but so far after a few weeks, no battery degradation.
Those are the only two that are currently available in quantity, and work in a real freezer.
The big advantage of those two is that they are also contact sensors - if you put them on the inside of the door, you can be notified when someone has left the freezer door open. Please note: they have a "open/close" distance of approx. 1" - which is much larger than most open/close contact sensors.
Please note that many sensors are ok for fridge doors.
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Can I strongly recommend the ecowitt WH31? These are inexpensive 915 MHz sensors that integrate locally with Hubitat via the ecowitt gateway.
The gateway is about $30 (about $25 right now) and supports all manner of sensors (temp, pressure, humidity, soil moisture, leaf wetness - just an incredible plethora of devices).
As I mentioned earlier, after it is setup, the gateway integrates locally with Hubitat. In addition, ecowitt offers a free cloud service, which you don't have to use if you don't want to. I am only mentioning it because provides really good long-term data storage and graphing capabilities (which I use) in addition to support cloud alerts (which I don't use).
Sensors take regular AA batteries that last a very long time. Here's what the graphed out data for the last week for my kitchen freezer looks like (both temperate and relative humidity are plotted):
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@jerrythreet There's a post somewhere on this forum where someone has carried out some long term testing with various devices but I can't for the life of me remember who it was/where it is. Maybe one of the other forum regulars is aware of it and can link it if they know where it is...
You can just experiment with the closing gap between the contact and magnet to make it more sensitive. Of course a temperature probe would work better as it could indicate an issue other than the door being left ajar.
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If you can find these or the V1's on Ebay they work great. I don't use the contact part I just put them in the refrig or freezer and watch the temp. They have caught a door being left open several times, just by the temp notification rule I have setup
I also use a Samsung SmartThings GP-U999SJVLAAA multipurpoase sensor in the refrigerator in our house. It has the added feature of notifying anytime the door is opened via the acceleration sensor.
ALl of my V1 contact sensors I u
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I'm for that, on the door. Even the Visonic 350 is fine for that. Got one one on an old garage frig that takes a deliberate push to close. Tells yah 3 minutes later if it didn't get shut.
But now for the deep chest freezer, that's a different story. That isn't a door issue, that's a fear factor that the thing is gonna give out when I least expect it. And SOOO that is indeed a temperature monitoring job. But I don't like putting the Zigbee sensor + battery in the deep freeze.
So...
I use the SmartThings multi sensor. It’s a pretty nice temperature sensor and seems to work fine through fridge / freezer doors.
I use a fibaro flood sensor, well it's actually a flood/temp/vibration FGFS101 or something like that. It regularly reports temp, and pulling the door open sets off the vibration/tamper feature. It's the Z-wave plus version
i still use the st814's unfortunately can't find them anymore but they had 3 aa batteries and you need something with lots of large batteries to really last in a freezer (are you listening manufacturers) ... Its not just about being cold rated..
they lasted a good 6-9 months.. Nothing else does in a freezer and drilling a hole to put a probe through is not a real solution in my book.
That's some slick stuff. I'm going to have to look at it further.
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Hue motion sensor. They were in stock at Home Depot last time I was there.
Looking at old posts, has been in freezer since at least Feb '21.
how does a temp sensor work in a bag.. I guess it is delayed as the air in the bag has to cool off?
It works just fine.
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Plus, if you really wanted to, and the freezer had a light, you could key that since the sensor also senses brightness.
Does the PIR sensor work in those conditions? It would also make a great ice cream thief alert.
Yes it does. I just dragged myself off the couch, laptop in hand, and opened the freezer.
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not for me.. that is why i got mine in the first place.. we had a freezer compressor die even though the light was on and it was running.. didnt know till we opened the sucker.. took days to get that smell out of the basement once opened.
