Best Way To Monitor A Garage Refrigerator

I noticed while poking around at that the Fibaro water sensors also have a temperature sensor and these have terminals to wire them to an external 12 volt power supply.

$60 for the Z-Wave Plus model.
$30 Z-Wave - not-plus (also supports the external 12 volt power supply).

Iris V2 contact sensor is what I use as well.

I have one in the garage freezer and one in the house fridge (due to design/layout).

Batteries have been in about one year.



IRIS V1 contact sensors inside of two deep freezers here. Batteries read (23%) low but last for a year or more. Rock solid both out in a detached garage.

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Iris V 1 or V 2 is the same as the one we’ve been discussing, right?

Any problems with the adhesive sticking (or not) to the inside of the freezer?

Iris contact V2 is the 3320-L.

As mentioned, there's a seller on ebay that does lots of 10 on the motion sensors that has the door sensors without magnets or batteries cheap. That said, I bought 10 motion sensors listed as no batteries and they all had relatively fresh batteries and the pull tabs still in them,

Stick a small rare earth magnet on the side and they'll report closed.

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Maybe try with a Sonoff TH16 (or TH10) with an external sensor. The sensor is a DS18B20

I think somebody here developped a tasmota firwmare or a more customized firmware for Hubitat.
I have the sensors but didn't try the firmware update so far. I need external sensors for various projects but had no time for them.


Both the magnet and the sensor need to be inside the refrigerator/freezer. Are these not secured using something like 3M double sided foam tape? I would have thought that there would have been a fairly good chance that the 'sticky' would have degraded with time due to temperatures (primarily the freezer). You haven't experienced this?

LOL, the (supplied) magnet is scotch taped, perhaps two wraps, to the sensor and set on a shelf or bin.


I could probably stick a small neodymium magnet to the side and call it good too.

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I've had a Xiaomi temp sensor in my freezer and another one in my fridge for 3 months. Yeah the battery has read like it's close to death or beyond for most of that time. But actually, surprisingly, I've found the devices continue to work! It's certainly easier than a wired solution.

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I had to warm and dry the area on the initial install, but they remain in-place after that.

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So you are stating that you don't use the contact capability of the sensor but rather only the temperature monitoring capability, correct?

Are they IRIS "special" version of Zigbee or do they work with any Zigbee hub?

The Iris contact sensors are made by centralite and supported by Hubitat.

For the V1 sensors, Hubitat has a native driver. For the V2 sensors, they get picked up as generic zigbee.

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Correct. I never really bothered to work any contact use and just set them inside the fridge with the magnet taped to the sensor to use for temperature.

While some of the new LG appliance combo we installed are smart (remote start oven, status notifying dishwasher, dumb microwave), we chose a "not door in door" model fridge which doesn't' have wifi but does have a local door alarm. The garage fridge is the 20 year old Kenmore (Whirlpool) that just keeps on chugging. It pretty much holds beer and wild game and extra frozen stuff that doesn't fit in the counter depth kitchen fridge.

Understood. But why do you bother taping the magnet to the sensor as you are not using it? Does the magnet need to be present in order to get the temperature?

No, I just don't want the sensor to show open in the dashboards.

can I just throw a ST multipurpose sensor in the fridge, do I need to put it in a container or ziplock it or is it ok in there with nothing.

I have an Iris/Centralite contact sensor sitting on a shelf in both freezer and fridge. I recall reading from JDRoberts on the ST community that batteries need to breath so putting them in bag may affect them. I haven’t had any issues with either sensor other than freezer reporting battery at 0% yet it’s still reporting temperatures. But that’s not an issue for me since I have a NodeRed flow monitoring my batteries and letting me know when a device hasn’t reported any type of event in 24 hours.

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That's what I did with my Xiaomi's and they continue to work fine after 3 months.

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I use the Iris contact sensors also. They eventually fell off so I cleaned the spot with rubbing alcohol and used 3M tape to stick them back on and they haven’t fallen off since.