New Ruuvi PRO

The days have arrived the new Ruuvi PRO.
Of course I was very curious about the accuracy, compared to the normal version.
Unfortunately, I was disappointed!

One thing in advance, I love the Ruuvi Tag sensors, just a pity that they do not display the humidity very accurately!

Just like all other versions, the humidity is too low, the temperature is so far Ok.
I have now certainly already checked over 100 Ruuvi Tags and all, show basically too little humidity.
In the beginning it was sometimes up to 10%, then with newer versions up to 6% and now with the very new and Pro versions about 3-4% always too little.
The problem is that it is always too little, no matter which Ruuvi day is tested and that is just not normal!
Therefore, I assume a software problem, as the moisture data are read out.

For the tests that were made, high quality devices from Rotronic, Testo and Trotec were used, as well as the sensor Push and Sensirion SHT31 SMART GADGET.

None of you users have the same problem?
I can not imagine at all.
What can be done to solve this problem?

Who has had the same experience?

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Hi Wolfgang,

Sorry for your bad experience. For humidity measurement there cannot be big difference compared to standard RuuviTag as the sensor is exactly the same.

We have discussed about this topic several times and also did tests with calibrated devices. With new Sensirion SHTC3 sensor there has been a very few cases where humidity sensors has no been inside the Sensirion accuracy tolerance when they have been tested in a controlled environment. It’s know fact that the Goretex membrane will slow down the humidity measurement, especially the last few percentages but eventually it won’t affect to the accuracy.

Can you describe your test setup and tell what is the humidity when you are making the tests?

To be able to define what is the actual reason, the only way is that we send you one device which is verified to be accurate and humidity calibration bag which will convert humidity inside a small container to 75%. There are also long delay with humidity calibration bag before it converts the container to 75%.

Reference humidity is here 75% +1%, and RuuviTag Pro shows 75,07

Thanks for the info.
The only strange thing is that not a single RuuviTag shows more humidity. Eigendlich always too little. There should be but also times where 2-3% more is displayed.

I make tomorrow times a picture of my test setup.
He is in an airtight box with table salt and water.
The Sensorium sensor shows very good values around 75%.

The sensors are now about 30 hours in the can.
Let’s see how the values are tomorrow.

Hello, attached are a few screenshots from my test.
The test lasted 54 hours in the closed case!

I’ll do another test now, with open Ruuvi case.

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My further tests have shown that the Ruuvitag in the upper humidity range, so at the 75% are quite good. Only in the normal range 20-22 ° C and 50-60% humidity, basically too little display. Which is very strange. Have you also carried out tests in these ranges?

Sensirion SHTC31 datasheet shows typical tolerance of ±2%RH Across the entire range.

A problem I have always had with all the values presented is that they are presented with a precision, i.e. hundredths, which is scientifically improper and usually within the range of noise. This presentation leads the user to expect much more accuracy than should be expected in this class (read co$t) of device. This becomes obvious when in a static environment reported value constantly changes and does not indicate a “trend” It should be noted that the least expensive Rotronic PC33 is $117US each.

The Bosch BME280 sensor required a somewhat complicated formula which included part specific values stored in the part. I found it quite interesting (for lack of a better word) the the code provided by Bosch included, as the last step in the humidity calculation, setting the value to 100% if the calculation produced a value over 100%!

Thanks for this info!