Different temperatures

Hello guys,

What is the margin of the error of the temperature sensor?

I have three ruuvitags updated with Eddystone fw and telemetry enabled . Placed them to at the same place to check does they show same temperature. Nope.

Temps after 1 hour wating.

  1. 22,25 C
  2. 19,0 C
  3. 20,5 C

I’m going to use them in environmental analysis of client’s real properties.
So if the sensors error is constant, I could calibrate them and use correction while saving the data.


Eddystone firmware uses nRF52’s inbuilt temperature sensor, which is not very accurate. I think the specification was ±2 C, you can look up the exact figure on datasheet.

For more precise environmental sensing, I would recommend the experimental Sensortag firmware: https://github.com/ojousima/ruuvitag_fw/blob/feature-sensortag/builds/distribution_packages/sdk12/debug/sensortag_06.zip . The sensortag firmware sends data in BLE advertisement packets, you can find the specification here: https://github.com/ojousima/sensor-protocol-for-eddystone-url/tree/feature-sensortag2 .

Please note that all of above is experimental, so bugs are to be expected. Idea is to merge the firmware into official Ruuvi software in a few weeks. If you’re on a tight schedule, please ask Lauri for access to our slack channel (info@ruuvi.com) and I’ll see how I can help you.

Kiitos Otso!

Sensortag installed and data received. Parsed with PHP successfully!

Check php example: https://github.com/dimamedia/ruuvitag_format3_php_parser
Working demo: https://dima.fi/ruuvitag.php?hex=0x02010411FF99040336175ABFF8FFE5FFCA03D00B4D

I’ll check tomorrow for sensor’s accuracy.

At this moment there is no tight schedule in my project. I have to create a demo with 3 ruuvitags and RPi3 for remote data analysis to my company. If it will be successful, we will order 10 more tags for bigger sensor grid :slight_smile:

Looking forward for an updates in sensortag fw!


Now updated SensorTag fw to all three tags and sensor’s data is quite the same. Just perfect, no need for calibration :slight_smile:


The specification found at

It says that for the NFR52832, the built in temperature sensor measures the chip temperature with an accuracy of +/- 5 Deg C. Most home digital temperature sensors will give an accuracy of +/- 1 Deg C and the good ones will get up to +/- 0.1 Deg C.

Unfortunately for that reason, this chip won’t meet my requirements. But I totally love this project !


You could consider using RuuviTag+ with all the sensors, as there is BME280 onboard. The BME280 has absolute accuracy of +/- 1 Deg C over 0 … 65 C range and resolution of 0.01 C.

Ruuvitag with all sensor have actually three temperature sensors to chose from :wink:

Info from ruuvitag site:

Advanced model (with all the sensors). BME280 = temperature / humidity / air pressure. LIS2DH12 = 3-axis ±16G accelerometer. FYI: This model has totally three (3) temperature sensors onboard (nRF52 + BME280 + LIS2DH12).

Can Otso or someone else please confirm this:

The basic Ruuvitag is only capable of +/- 5 degrees Celsius accuracy.

If yes, is the measurement error in any way constant, so that I could calibrate on the receiving end to make the tag in any way usable as an outdoor temperature sensor?


Model what Ruuvi sells currently online has all sensors on board. There was as RuuviTag without sensors available on Kickstarter but now it’s only available in large quantities.

“Advanced model (with all the sensors). BME280 = temperature / humidity / air pressure. LIS2DH12 = 3-axis ±16G accelerometer. FYI: This model has totally three (3) temperature sensors onboard (nRF52 + BME280 + LIS2DH12).”

You may find BME280 sensor spec here.

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