How To gather Data From sensor usingb nrf 52840 dongle

[Pranav Nad]

Hey guys, 

Recently I have been working with the nrf 52840 dongle and my goal is to use the dongle to communicate with a sensor and read values from it. So far I have been able to connect to the sensor and read its services/ characteristics but I need help in regards to what to do next in order to gather actual values from the characteristics. It would be awesome if I could get some direction as to what I should do next in order to read the sensor data. Thank You!

[Einarh]

Hello

It's not really clear to me what you are trying to do. Is your dongle and the sensor on the same board, or is your dongle communicating with another BLE device that has this sensor? What is connecting to what, and what device is reading the data?

Also, what SDK are you using?

Best regards,

Einar

[Pranav Nad]

Hey Einarh,

Sorry for the confusion. I am using SDK 2.0.0. I am trying to connect the nrf dongle to my sensor via BLE, in which Iconfigure the dongle as the central device and the sensor as the peripheral. I want to know how to read the sensor values, such as temp humidity, from the sensor. So far I have been able to  connect to the device, and do a GATT discovery on the device where I found the temperature characteristic. But I am having trouble with the last step which is using the temperature characteristic to get actual temperature readings. Hope this clarified things. Thank you !

[Einarh]

Ok I see.

What are you getting through the temperature characteristic right now if you're not getting actual temperature readings?

What device is reading the sensor? I assume you're not programming it yourself?

-Einar

[Pranav Nad]

Hey Einarh,

Right now I am telling the dongle to read the sensor and I am not able to program the sensor. Also so far I have only been able to print the characteristic data using the chrc_attr_data_print function. I was wondering if there was any sort of function I can use to print the characteristic values. 

Thank you!

[Einarh]

Hi

Have you looked at samples that do similar things to what you want to do? Such as this one for example:

https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/bluetooth/central_ht

-Einar

[Pranav Nad]

Hey Einar, 

I am able to get the value handle for the characteristics can you show me the documentation for functions that use the value handle to get the characteristic values. any examples that do this would also be great. 

Thank you!

[Einarh]

You should be able to use bt_gatt_read(), see bt_gatt_read_params for available options.

Eventually you can use bt_gatt_subscribe() if you want to use notifications.