Creat and send a file over BLE

[Piwy]

Hi,

I use NCS 2.4.2 and i want to save data sensor with a hight frequency in a nrf5340 device and send it over BLE to a nrf52840 dongle device. The nrf5340 is the peripheral.
The sensor data are at a ver hight frequency (more than 400Hz), that's why i need to save it in a file and send it by block.

I need help to find the right solution to perform this. I saw Throughput Service, Objet transfer service, NUS but i can't figure out what is the best solution.

I use coded phy also.

Regards,

Pierre-Yves

[Vidar Berg]

Hi Pierre-Yves,

To efficiently send the data, I'd suggest keeping it in a RAM buffer until it is sent. I'm not sure how many bytes each measurement is, but the more you can fit into each notification packet, the better.

I use coded phy also.

This will greatly reduce the theoretical throughput of the connection. If possible, it would be better to increase the TX power using an external PA/LNA such as the nRF21540 and stay on 1M.

Best regards,

Vidar

[Piwy]

Do you have example of this ? and what services do i need to use ?

each mesurement is composed of 3 float for the 3 axes and i also need to have the time in milisecond hour per hour, it's a long uint i think. Then one mesurement should be around 20 bytes each 1ms or each 2ms .

I use already a nrf21540 and i need to use phy coded because  i need long rang connexion

I tried to use throughput but with the sample central and peripheral when i config in coded_s8 it's really too slow instead of when i use ble nus

Regards,

Pierre-Yves

[Piwy]

It's because i parse many other data as i said, if it's possible to i don't want to print them because i print many other data, maybe too much to be able to print them all, is there other way to do it while the other data are being parsed ,

[Vidar Berg]

You can read the serial data in your C program without printing it anywhere.

[Piwy]

i need to print it in my dongle in the console shell, or there is another way ? In bluetooth shell sample to be able to have the data from my device i need to shell_print it or printk or printf it in the shell consol of my device. I do like this to parse my acc data currently but i want to know if i can find another to do it ?
I have many other data in notify that i print in the console that's why i want to find another way

[Vidar Berg]

You can filter the logs in your C application and only redirect log messages not related to the accelerometer to your console. Another solution could be to change the firmware on the dongle to enumerate as 2 COM ports and only send accelerometer data on one of the ports.

[Piwy]

Hi,

My issue of log is in the firware of the dongle that's i have difficulties.
The second solution seems really interesting, how can i do that ?