Bluetooth: Direction Finding Central and Peripheral Sample Code

[mgl]

When working with the direction finding central code, would we need to have the antenna array connected to the central development kit and then have another kit running the regular Bluetooth: peripheral sample code? I am working with the nrf5340 development kits and u-blox ANT-B10 antenna array board. I am also having trouble finding the correct connector for the antenna array board. Any help would be greatly appreciated. 

[Elfving]

Hi,

You are right on track.

Use the antenna connector J1, right at the end of the DK, above the logo.

 

For more on how direction finding works, I hope you've seen the WP on it. Though note that there might be some discrepancies between what the WP states and how the BT SIG spec defines its function, since the WP is mainly focused on the HW capabilities on the nRFs.

Regards,

Elfving

[mgl]

I understand that I need to use the antenna connector J1 but what part do I need to make this connection?

[Elfving]

An SMA to SWF cable.

Regards,

Elfving

[mgl]

Thank you. So something like this:

https://www.mouser.com/ProductDetail/TE-Connectivity-Linx-Technologies/2478574-1?qs=sGAEpiMZZMtYRSmx0IAE0uxleH0x23v9Rb8Lznv66DXZk6DMb8jjMQ%3D%3D

Is this right?

[Elfving]

I can't recommend specific products here, and I don't really know what the Antenna array you have requires (so it might be worth asking/checking with u-blox about this directly). But make sure that you have the right SMA connector. The antenna array I have requires a male SMA, the product you're linking to uses a female one.

Regards,

Elfving

[PaKa]

The ublox antenna array has the Nordic device on the antennnaboard directly connected to the array so no cables should be used/needed. For the transmitter you only need the single antenna so no external antenna needed.

From the ANT-B10 webpage:

The ANT-B10 is a compact antenna board designed specifically for Bluetooth angle of arrival (AoA) direction-finding systems. It features eight patch-antenna elements in an arrangement that offers optimal performance in the presence of multipath effects. It measures the angle of an incoming Bluetooth Low Energy (LE) radio signal with high accuracy, and in conjunction with at least two more ANT-B10 boards and positioning engine software, it can determine the precise position of a Bluetooth LE device in an indoor environment.

ANT-B10 features the NINA-B411 Bluetooth 5.1 standalone module, programmed with the u-locateEmbed* software, which implements the unique u-blox direction-finding algorithm. It includes a widely available standard pin header that provides a digital interface to the application board, thus forming a complete AoA anchor point. Alongside the EVB-ANT-1 development platform (part of the XPLR-AOA-3 kit), the user can plug the two boards together and have an AoA anchor point within seconds.

[mgl]

Which boards would I be plugging together in this case to create an AoA anchor point if I don't need any cables? I am just trying to create the system using the ANT-B10-00C board and nrf5340 development kits. I do not have the EVB-ANT-1 development platform or anything else that comes with the XPLR-AOA-3 kit. 

[Elfving]

Hi again,

PaKa said:

ANT-B10 features the NINA-B411 Bluetooth 5.1 standalone module, programmed with the u-locateEmbed* software, which implements the unique u-blox direction-finding algorithm. It includes a widely available standard pin header that provides a digital interface to the application board, thus forming a complete AoA anchor point.

It does sound like you do not need anything more than the b10 for the locator, as that already has the NRF on it. 

PaKa said:

Alongside the EVB-ANT-1 development platform (part of the XPLR-AOA-3 kit), the user can plug the two boards together and have an AoA anchor point within seconds.

Even though it mentions using another board here, it seems a bit like it isn't necessary. Atleast I do not think you need an antenna cable. You should have a look at the ublox docs or contact ublox about this. 

Regards,

Elfving

[mgl]

But I would still need to connect the B10 to my nrf5340 somehow, correct?

[Elfving]

No my impression is that the nRF is already onboard. The B10 contains a NINA-B411, which contains an nRF52833.

You do need another nRF (for instance a DK) as the direction finding tag though. 

It might be an idea to check this with ublox though.

Regards,

Elfving

[mgl]

Okay, thank you. Would an nrf5340 be compatible for the tag with the antenna array having the nrf52833? And would I need to flash any code on the antenna array board and power it?

[Elfving]

mgl said:

And would I need to flash any code on the antenna array board and power it?

Well yes you would have to power it. And I assume you do not need to flash anything to it.

Though I am not sure about the specifics here. It would be best to check this with the docs from u-blox.

mgl said:

Would an nrf5340 be compatible for the tag with the antenna array having the nrf52833?

Yes, given that the u-blox solution follows the spec.

Regards,

Elfving