Accessing all mesh devices from mobile phone

[ftjandra]

Hi,

I've used the nRF51822 in the past to make sensors that connect to a mobile device. Basically it worked just like every other non-mesh BLE device:

1. It advertised itself to be scanned by the mobile device

2. Mobile device connects.

3. Data can now be sent back and forth.

I want to make a new sensor that uses the nRF52840 in a mesh configuration in order to increase range. I've played around with the light switch mesh example and have it sending bytes instead of just an onOff bit. Is it possible to make the mesh nodes 'equivalent' to my old sensors (i.e. could I connect to them without modifying the mobile app)? Basically, what I am trying to accomplish is to make all the mesh nodes appear as if they are close by even though some may be far away and 'hopping' through the mesh. All while still being 'backwards compatible' to my old sensors. Is this possible?

Thanks.

[Joakim Jakobsen]

Hi.

Are you planning to have the new sensor operate in the same way as the old sensors you have? i.e that the sensors are BLE devices, but have the possibility to send data to a Mesh network? Or do you want the new sensor to be developed as a Mesh node, provisioned into the Mesh?

Best regards,
Joakim

[ftjandra]

I want to see whether it's possible to do the first, i.e that the sensors are BLE devices, but have the possibility to send data to a Mesh network?

Thanks.

[Joakim Jakobsen]

Both is possible.

If you add proxy nodes to your Mesh, these nodes will be able to communicate with the BLE nodes, and are able to relay the information to the Mesh. That is actually how the nRF Mesh app works, because mobile phones "can't" communicate directly with the Mesh.
Alot of information about this is available, both here on devzone and on bt sig official website.

I would also like to note that it's possible to develop your sensors as LPN as a part of the Mesh. This way your sensors will behave pretty much the same as a BLE device, sending/receiving information on a given interval and then going back to sleep.

Best regards,
Joakim

[ftjandra]

What is the difference between a proxy node and coexistence, or are they the same thing?

[Joakim Jakobsen]

No, they are not the same thing.

Proxy node;

"The ability to receive and retransmit mesh Messages between GATT and advertising bearers. A Node that supports the Proxy feature and has the Proxy feature enabled is known as a Proxy Node."

The coexist examples demonstrates how nRF5 SDK for Mesh and nRF5 SDK examples can be used together at the same time. It is built around two examples and has a mesh part and a BLE part.

Best regards,
Joakim

[ftjandra]

So if I wanted to add another service like the Device Information service, that would then be an example of coexistence? Or could that be added without needing both SDKs?

The difference between a proxy node and the coexist examples is still not clear to me. In coexistence are there then two advertisements, one for the mesh and one for BLE? Is coexistence basically running both at the same time? I don't think I really need that. With the light switch mesh example I was able to modify the advertisement to add manufacturer data that I need and the mobile device can obviously connect to it (i.e. nRF Mesh app or BLE scanner app). Now I just need to be able to add the Device Information Service and a custom service.

[Joakim Jakobsen]

The documentation page about Integrating Mesh into nRF5 SDK examples might provide you with some useful information.

Have you looked at the information there?

[ftjandra]

I think I can make it work with a proxy node. In the light switch mesh example, it looks like both the switch and the light are running the proxy service. How can I send it some data? I don't see how to send any data via the nRF Mesh app.

Also, looks the proxy service supports notifications so that the phone can be automatically kept up-to-date without having to query it all the time, correct?

Thanks.