What are the factors that influence the duration for which distance measurement will occur (Using nrf_dm sample).

[Madan C]

Hello, guys,

I am working on distance measurement project using two nRF5340DK (nrf_dm sample application). I found duration for which the distance measurement between two DKs happens is random, so can I please know the factors effect this duration and also can we control this duration in code.

Also, can we control interval time between two distance measurements in code.

Regards,
Madan

[Madan C]

Hi Simonr, 

Thanks for your reply

I believe there may have been a misunderstanding in my previous explanation, and I apologize for any confusion caused.

My actual question is the number of distance measurements obtained varies with the distance between BLE devices. For example, in case 1, when the devices are approximately 1 meter apart, the number of measurements recorded is 35. However, at distances of 5 meters and 8 meters, only about 5 measurements are recorded.

Could this discrepancy be attributed to a shorter advertising interval when the devices are closer, resulting in more frequent measurements? Or are there other factors influencing this behavior? Additionally, is there a way for developers to configure the system (in code) to maintain a constant number of measurements regardless of distance?

Regards,
Madan

[Simonr]

Oh, I see. Sorry about the confusion here. Can you confirm you have the measurements running at the same amount of time in all cases, and how long exactly is it you're measuring for? I don't think the advertising interval changes, but since the distance measurement itself takes some time, it can vary a bit, but it shouldn't vary this much as far as I know. 

I think the main ways to edit how many rangings you need is to change the Kconfig options CONFIG_DM_TIMESLOT_QUEUE_COUNT_SAME_PEER and CONFIG_DM_TIMESLOT_QUEUE_LENGTH that define how many measurements are scheduled. The more measurements scheduled, the more will take place. 

Best regards,

Simon