11-25-2016, 05:22 PM
After much testing and evaluating the results are that you can get absolute readings by taking out the sensor out of the enclosure. Inside the temperature offset is 1 degree (in case the device sends data not often than once per 2 minutes) (need to check a bit more for smaller intervals). This is done mostly by the USB2Serial chip (60 mW) and the CO2 Sensor (~20-50 mW)
The CO2 Sensor i can turn off, but the only way to turn off the USB2Serial chip is to dedicate an USB cable for powering the device, and carefully cut through it's shielding and disconnect the Green and White (D+ and D-) lines.
Yet the investigations showed that the offset is consistent regardless of the ambient temperature. Here results from two different sensors - one is inside the enclosure, the other - outside
![[Image: tempoffset.png]](https://s21.postimg.org/g6wd2jz6v/tempoffset.png)
So what i will add as an option is to be able to set temperature offset. It will be different for the different types of devices, but i will preset it. Also i need to change the firmware in a way that there are settings that are not cleared when factory reset is being done, as they are rather related to the hardware of the device.
Apart from this - the sensors that i use have an accuracy of +- 0.4 - 0.5 degrees
For the WiFi Temperature Sensor - i will use the bigger enclosure, as there the offset was 3 degrees, which is quite a bit.
The CO2 Sensor i can turn off, but the only way to turn off the USB2Serial chip is to dedicate an USB cable for powering the device, and carefully cut through it's shielding and disconnect the Green and White (D+ and D-) lines.
Yet the investigations showed that the offset is consistent regardless of the ambient temperature. Here results from two different sensors - one is inside the enclosure, the other - outside
So what i will add as an option is to be able to set temperature offset. It will be different for the different types of devices, but i will preset it. Also i need to change the firmware in a way that there are settings that are not cleared when factory reset is being done, as they are rather related to the hardware of the device.
Apart from this - the sensors that i use have an accuracy of +- 0.4 - 0.5 degrees
For the WiFi Temperature Sensor - i will use the bigger enclosure, as there the offset was 3 degrees, which is quite a bit.