Shelly HT gives higher temperature after FW update

I performed the firmware update of the HT sensor and since then the measured value is much higher than the room temperature. The sensor now measures about 31°C while the room temperature is about 21°C. (Measured with IR thermometer on my desk)

I've never used the offset setting before and I'm surprised it makes such a difference. Before the update, the measured value was a bit higher than the room temperature, but never so much.(2 to 3°C)

To make sure that the location of the sensor has no influence, I placed the sensor in several places. In all places the sensor gives around 29°C at a room temperature of 21°C.

Which I did notice: The deviation is almost gone when the sensor has not been used for a while (a few minutes without power) Within 2 minutes the deviation is present again.

The sensor is powered by the USB adapter and 20201124-091711/v1.9.0 is the FW version on which the sensor works.

What can be the cause and can this only be solved by using the offset?

In the image below you can see when the update is installed and when i used the offset.

A late reaction for this problem. Due to several isues it toke some time for the problem was solved and that i post it here.

The steps to follow by shelly technician.

Zitat

In regards to the H&T

We are advising you to try something. Please revert the offset configuration and leave it in 0

Please remove the battery and press the reset button once. After that add apply the battery and leave it for a while until the device try to calibrate itself. In the meantime, you can check both value records in the webUI and application.

In order to check the values in webUI you need first to wake up the device.

I normally use the USB adapter to power the H&T sensor.

I reset the sensor and used a battery to test. The measured temperatures were immediately as before the problems after the reset was given.After this I used the shelly USB adapter in conjunction with the phone charger.After this I used the shelly USB adapter in conjunction with the phone charger. Also with the phone charger the temperatures were normal.

This seemed to solve the problem without really having a clear idea what it was.

Reconnecting the sensor to the old USB net adapter brought the problem back. The old USB net adapter checked with a phone and tablet and both devices also had problems charging with this USB net adapter.

So the cause was the old USB net adapter.I have now connected the sensor to USB hub of the PC screen and everything works again as expected.