No connection at High humidity(temp)

I have four Tags in different parts of the house. The two closest ones work fine. The ones just a little farther away don’t get through. I live in a warm climate (Virgina, USA) the daytime teemperature have been running at 95F+ (35C) when it gets this warm :<( the outside Tag is no longer is visible. And a Tag 15 feet away also no longer reports.

Are you using the batteries shipped with the Kickstarter units? They are specified to work from -40C to +85C so the temperature should be not the problem. Actually, all the batteries available should work in 35C perfectly fine. Usually, general CR2450 and CR2477 batteries work from -20C to +65C.

Could you try to switch the batteries between the working and non-working units to see if the problem is with the batteries?

Original battery! Still a 3 volts

We have had a tag running in a sauna, so high temperature or humidity should not be a problem. How you are receiving the data? Could you take a look at the RSSI readings, for example using nRFConnect app?

I have two tags less than (as the crow flies) less than 30 feet away, the rssi levels vary (why so much?) from -70dbm to -100dbm, but suddenly no reading from the two fartherest sensors. Again it’s warm but why the change. Battery levels are at 3 volts.

Just to clarify if I understood correctly:

  • You have 4 tags
  • 2 closest tags can be heard.
  • 2 furthest tags cannot be heard anymore.

The default firmware ships with +0dBm transmission power, if your use case is to log data near your property you could use the unofficial logtag firmare. That firmware sends at +4dBm once per ten seconds.

Signal strength can vary for a lot of reasons - if something is between transmitter and receiver, if the angle of either changes, if nearby devices happen to broadcast at same channel etc.

I have changed the firmware on all the tags to +4dbm every 2 seconds. I also set the hires flag to true to start the tags in highres mode.

We’ll replace the 2 tags with poor range. I’ll PM you the details.

First off, I don’t think the tags are the problem. I have five tags all together, and I have swapped out the tag location I have been having the most problem with. That location is outside the house about 35 feet (~10m sorry in the USA:>) away and one story down. I had this tag hanging on a nail mounted vertically. I have changed this to horizontal, and it seems to help.

The main program that I am using with the tags is running on a raspberry pi zero W. The program is written in node js acting as a web server. This program collects data from the tags every minute and updates my simple web page. Basically I scan for tag data for 45 seconds and the post the data collected.

I have a second node js program running that scans the tags (again once a minute) and displays the data.
I will modify this program to collect the data to a database, and send you the results. I can also send you the web page address (won’t post it here).

To finish up for the moment, I can now get data from all four running tags but need to scan for a least 45 seconds. Why that long when the tags broadcast every 2 second I don’t understand. The rssi values are all over the map, but the ‘bad’ tag values are not that different from the ‘good’. I send you the data as soon as I have it.

Thanks for all your help


I have also had problems with one unit in a high-humidity environment. I use multiple tags to monitor various points around my company. Two of the tags are in incubators (nearly 100% humidity and 37 C). Both of those tags stopped communicating. When I investigated one of them I could see clear signs of corrosion. The tag was able to be refreshed for a few days by gently flexing the board (happened while removing and replacing the battery). My guess is that there is/was a cold joint somewhere on the board or perhaps some delamination and corrosion of a buried trace exposed in this way. Has there been any failure rate testing in high-humidity environments (aside from the one sauna example).

In really humid conditions, circuit board could be coated:

We haven’t coated RuuviTags with this stuff but other electronics, yes.

I’ve thought about such things, but have been concerned that it could block the ports of the humidity sensor chip. Also I suppose one would have to mask the contact points to the battery, and those surfaces seem to have much of the corrosion.

The humidity may be creating a leakage pathway that drains the battery prematurely. I didn’t notice on the first one that failed, but on the one that I found failed today, the battery could only make 1.6 V. Another battery brought it back online. The tag was in-service in the ~100% RH incubator for maybe two months.

it seems that replacing battery wont help, new battery lasted one month… the leakage path probably needs cleaning (at least in my case).