Humidity Temperature value displayed wrongly

[SUK]

Hi, I am interfacing a temperature and humidity sensor (si7021) to Nordic nRF52 development kit board. The sensor works fine and I can read accurate temperature (23 degree Celcius) and RH (44%) values. But when I transfer those values over BLE using s132 softdevice to a cell phone, the values of RH and temperature displayed on "nRF Connect" app are 626.67% and 62 degree Celsius respectively. I am using "Environmental Sensing" service (UUID 0x181A) and the RH (name: Humidity, UUID: 0x2A6F) and temperature (name: Temperature Measurement, UUID: 0x2A1C) characteristics represented by this service. Both the services and characteristics get discovered on connection (as shown in Discover.png) and the value transmitted for RH is shown in "RH_value.png". Please let me know what is wrong. Thank you. RH_value.png

[Roger Clark]

Which code are you using for these services?

They don't seem to be listed in the SDK components\ble\ble_services

[SUK]

Yes, they are not listed in the SDK. I am using the "ble_app_hrs" example and adding the RH and temperature reading to that code. Let me know if you need a code spinet to take a look.

[Roger Clark]

I suspect you code is not putting the correct values into the characteristic.

Either that, or there is a bug in Nordic's App.

Have you looked at the raw data and compared it with the Bluetooth spec to confirm you are sending the correct data

[SUK]

I checked with the BLE specs and did confirm that I am sending the correct value. I also noticed that Nordic does not support environmental sensing service. The ESS service requires many descriptors (like ES Measurement, ES Trigger Setting etc.) which are not present in the SDK. This service will not work with only the Client Characteristic Configuration Descriptor. The difference in values could be because of that. Roger, any ideas or comments on this?

[Roger Clark]

I looked at the ESS the other day, but decided it was too complicated for my use, so I just made a custom service instead which sends the data in a format which my app understands.

But, If you have to use an existing Phone App which supports the ESS profile, you will need to write all the code to support the ESS profile.