Temperature accuracy

Products & Services 🇬🇧 RuuviTag & RuuviTag Pro Sensors
1

I am wondering about the temperature accuracy. On ruuvi.com I found the following

  • Temperature sensor accuracy
  • Typical absolute accuracy ±0,5 °C @ 25 °C
  • ±1 °C @ 0-25 °C
  • output resolution 0,01 °C

On bonsch-sensortech.com I found, for BME280 (in RuuviTag, right?)

  • 0.5 °C at 25 °C
  • 1.0 °C at 0…65 °C
  • 1.25 °C at -20…0 °C
  • 1.5 °C at -40…-20 °C

I had put the RuuviTag in my freezer, set at -18 °C, and the RuuviTag showed -28.5 °C. I thought the freezer’s thermostat should be more accurate than that, doubting the RuuviTag, but then another RuuviTag next to the first one showed -27 °C, making me wonder if the freezer has a problem.

I also found some old posts saying that the RuuviTag has a 5 °C accuracy at sub-zero temperatures but Bosch claims a better. I assume the to-be-launched RuuviTag Pro is more reliable, but what is the latest on RuuviTag temperature accuracy?

2

Hello,

Bosch datasheet is the authoritative document on temperature accuracy. We have some variants with SHTC3 and TMP117 sensors providing temperature data, but as far as I know every unit we have sold through webshop so far has BME280.

Placement of sensor in freezer and refrigerator makes a huge difference, and many coolers experience pretty wild temperature swings.