Nordic Distance Measurement Toolbox, how to range with multi responders one by one more fast

[Zach Liu]

Hello,

I can get the distance between four NRF52833 device based on the distance measurement toolbox SDK 1.9.1, but the output rate is a little slow, less than 1 Hz. And the distance maybe fail for some devices at sometime, as follows:

Sometimes the distance just from one node.

So what should I do to make the distance measurement more reliable and get three distance for each node with a rate larger than 1 Hz. Anyone knows how to do this, I'd really appreciate it. 

Zach

[Elfving]

Hello Zach,

Unfortunately, I will have to get back to you on this after the holdiays.

Regards,

Elfving

[Zach Liu]

No problem. 

[Elfving]

Hello again, and thank you for your patience.

In the nrf_dm sample, what you experience is likely to happen. It depend on the synchronization process and number of devices. In the case of several devices, it is between which measurement will be made that is not controlled.

If you want to improve this, you can introduce a mechanism that will manage the addition of measurement request to the DM module. 

Regards,

Elfving

[Zach Liu]

So you mean introduce a mechanism to decide which one to measure, right? If yes, where can I get all the target address and then make the decision. During the synchronization process, does the devices will record all the other device found? 

[Elfving]

Yes, during scanning, a list of supported device is created. While the device acts as an advertiser, when scanned it checks this list. 

In the nrf_dm sample, the devices act as advertiser and scanner.

Regards,

Elfving

[Zach Liu]

So, the devices can be set as either a advertiser or a scanner in the nrf_dm sample, right?

For the scanner, once it has got the list of the devices around, then it can change its state to a advertiser, and then measure the distance. 

[Elfving]

Well in a way they are set as both. Both devices act as an advertiser and a scanner.

You could set one to only act as a scanner for instance though, but it requires changing the sample code. If the device only acts as a scanner then it will be initiator. Then another device should acts as an advertiser to act as reflector in the ranging procedure.

Regards,

Elfving