Oregon THGR228 Temperature accuracy

[Digit]

Due to some internal redecoration of our home, nearly all my Oregon Scientific sensors are currently in my office, with no more than 15 cm distance from each other.
This gave me some interesting material to think about which i'd like to share with you.
When i look at the humidity readings, there is no more then 1% difference in all the readings (33-34 % humidity). Ok.

However, when i look at the Temp readings, they range from 25.4 to 26.1 degrees Celsius:

1: 25.4
2: 25.7
3: 25.7
4: 25.4
5: 26.1

That's 0.7 degrees difference. I don't really like that.

I think i'll need to do something like calibration here. However, i have no idea (yet) if every individual sensor can be calibrated by calculating a simple offset.
Maybe the sensors have an offset to the "real" temperature that changes in time, which makes calibration useless.
Has anyone else ever done some research on this?

Regards,
Robert.

[Bwired]

Hi Robert,
I know they are really sensitive. Try putting them all in a quit spot no draft or other devices, a couple off inches apart.
Then let us know again, only sensor 5 seams really to be peaking.

[Digit]

Pieter,

At first the 5 sensors were laying on my desk, as closely together as possible. I thought that would be enough, but apparently not...

Putting the 5 sensors in a more closed environment (i put a box over them...) made the differences reduce to 0.1 degrees for sensors #1...#4. #5 kept a difference of 0.3 degrees.

Currently i'm logging the temperatures for these sensors, so i hope i can say something about the "stabillity" of the offset, especially for sensor #5.

Regards,
Robert.

[Bwired]

Hi Digit,
Thats exactly what I thought! These readings are much better. As I told the sensors are really sensitive!
For the THGR228 number 5, this one is sure a bit off!