Nicla Sense ME temperature and humidity inaccurate

[olboss]

Not a problem,

This is the result of: 

ioreg -p IOUSB -l -b | grep -E "@|PortNum|USB Serial Number"

Nicla Sense CMSIS-DAP@14100000  <class AppleUSBDevice, id 0x100002545, registered, matched, active, busy 0 (1055 ms), retain 18>

          "PortNum" = 1

          "USB Serial Number" = "CC57804E"

[Ciprian]

This is fantastic news, it would be really good to have a timeline for this, as the device was bought for accurate readings and currently it has issues. 

I will be following this thread to check for updates, specifically in the following 2 weeks.

[olboss]

Hi,

I wonder whether you have an update on this issue?

Currently, the Nicla Sense ME is essentially useless, I can guess the temperature more accurately than it can. If no update is available soon, I'd be happy for a refund or recall.

[Ciprian]

Hey Olboss, I don't know if you need it anymore, but I have done some testing and comparison against other sensor + linear regression to get the best values.

The graphs look like the following, I have only been able to get 8 data points, with more, the error could be less.

Use the function for correct temperature within 0.5Celsius error: correct_temp = 1.0095 * nicla_temp - 4.8051

Use the function for 1% error between 0-30% humidity range, and 2% error (approximated) with 30%> humidity: correct_hum = 1.4383 * nicla_hum -2.5628

Use the following formula for correct barometric readings: correct_pressure = 0.718/100 * nicla_pressure + nicla_pressure

These are all perfomed by myself and will not offer 100% accuracy as specified, but the error should be less 0.5% for temp and pressure, with 1-2% for the humidity depending on the range.

temperature regressionhumidity regression

[olboss]

Thanks Ciprian.

I think there's a massive question as to where the error is coming from, whether it's self-heating, or a software issure, or chip-dependent... and then whether the BSEC air quality values can be trusted. My guess is that they are derived (in part) from temperature and humidity, and are therefore equally inaccurate.

From my perspective, the sensor is currently useless.

It looks like Arduino provide the warranty. Next week I'll move the discussion over there, and request a refund.