Arre temperature/humidity sensors failing

Hardware
1

A few months ago, I installed some Arre temperature/humidity sensors. Earlier this week, two of them became unavailable and have not come back online despite HomeAssistant restarts.

I am looking at one of them now and it seems to be totally dead: it is not detected when scanning for a new device, short and long presses on the reset button have no effect, changing the battery has no effect and the unit’s internal light never shines.

Has anyone else had this happen? Is there something that I am missing? This is quite concerning.

2

I would make contact with the support of the maker of those to see if you can get replacements or just replace them with another brand.

3

So far as I can make out, there are no other Matter sensors that detect both temperature and humidity.

4

https://www.matterdatabase.com/category/temperature-sensors

I count 4 on that page and I have a swtichbot hub 2 that connects to my HA instance using matter over wifi and is a bridge for my switchbot bots that are bluetooth.

5

Looking at that page, we have the following:

  1. the LG temperature and humidity sensor, which is listed as “rumoured” and is not available;
  2. the very Arre sensor that I am having trouble with;
  3. a Meross sensor that is Bluetooth and wi-fi rather than Thread; and
  4. a Shelly sensor that is Bluetooth and wi-fi rather than Thread (and whose documentation gives no suggestion that it is Matter compatible).

From what I can see, the Meross sensor is huge. The Shelley sensor looks a little smaller, but does not have the little stand that the Arre sensor has that I need to make it work in my downstairs lavatory where there is very little space and I stand it on the protruding edge of the door frame.

6

What you can do when it comes to ones without stands is use say 3M Command Picture Hanging Strips (I use the large ones and just cut them down to fit) to have a stick on point for devices.

I have it holding power strips, the hub 2, my aoetec sensor etc and they hold well for a good long time and the come off clean as long as you keep that pull tab side as the side you cut down to should you need to remove it in the future.

7

I have just tested the batteries in both and found them to be flat. I only had one spare, which I have replaced, and the one that I replaced works. I am not sure why an earlier attempt at replacing the battery was not successful.

8

For reference:

I have 6 of these (including both older TUO branded sensors and newer arre branded sensors) that I’ve been using for a 1-2 years each, and haven’t had any fail.

However, I have found that CR2032 batteries seem to vary drastically in longevity/reliability/behavior, with name-brand batteries being much more reliable than cheap/no-name batteries, and cheap/no-name batteries often appearing to have sufficient voltage with no current load but then suffering from significant voltage sag under any current load. These sensors seem to have a relatively high cut-off voltage (I think around 2.75V), so unless you are using fresh name-brand batteries it is likely the batteries that are the problem. At this point, I only use Panasonic brand CR2032 batteries (from Mouser, as they have enough turnover to ensure you always get recent stock).

Using both the original batteries (that came with these sensors) and Panasonic batteries, these sensors last 3-4 months (with the original/shipped firmware; hopefully the new beta firmware being released now will improve this as promised). Once the sensor stops working, the sensor seems to continue draining the battery fairly rapidly until the battery reaches 0V. With the original batteries, the reported battery level was around 80% when my sensors stopped working. With Panasonic batteries, the reported battery level is typically around 30% when my sensors stop working.

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