Which chip & how many needed: ZigBee and Bt comm box

[v01d]

Please ignore Product Type I selected  - i set it to just select that to something.

I'm planning/designing a comm box, which needs to speak to ZigBee based nodes/sensors, and also nodes/chips with Bluetooth.  Further, I want then that same comm box to forward data from ZigBee and Bt  nodes it oversears on another  interface, likely also Bt, but used as direct to a client connected to this comm box .  (It could possibly be over WiFi too ).

My question is, how many ZigBee and Bt  modules do I need here, to effectively and simultaneously be able to collect data from these nodes or slave devices to this comm box, and forwarding it to the comm box client? 

Do I need  1 ZigBee,  and 2 Bt modules ?  Or 1 ZigBee-dash-Bt combo module  + 1 Bt?   The comm with nodes (or slaves) that my comm box will oversee shall not interfer or be independent of what it forwards  / sends to it's client. But also not to over-chip or make this costs reasonable.

Advice here is highly appreciated, this would be my first work with this technology.

[Elfving]

Hello,

how many ZigBee and Bt  modules do I need here, to effectively and simultaneously be able to collect data from these nodes or slave devices

Well that would depend on what you mean by simultaneous and effectively. We do support using Zigbee and Ble in parallel using MPSL, though that is not completely in parallel as only one protocol is being used at the time, with timeslots. Question is if that would be good enough.

(It could possibly be over WiFi too ).

We currently do not have any SoCs that support WiFi available.

Do I need  1 ZigBee,  and 2 Bt modules ?  Or 1 ZigBee-dash-Bt combo module  + 1 Bt?   The comm with nodes (or slaves) that my comm box will oversee shall not interfer or be independent of what it forwards  / sends to it's client. But also not to over-chip or make this costs reasonable.

So you could potentially do with just one SoC. Here you can find the ones that support Zigbee, along with a handy comparison between them.

Regards,

Elfving

[v01d]

Hello Elfving,

Thanks for replying.

Elfving said:

Well that would depend on what you mean by simultaneous and effectively. We do support using Zigbee and Ble in parallel using MPSL, though that is not completely in parallel as only one protocol is being used at the time,

So by guessing, this would be some kind of round-robin, one at a time?  Is there some kind of tech spec or a simulator tool to know how fast one can poll / comm with those nodes using just one Nordic chip which has both Zigbee & Bt ? 

Is there a significant time spent when you switch between Bt and Zigbee modes (or profiles, whatever is suitable terminology here), to poll the nodes ?

Elfving said:

So you could potentially do with just one SoC.

Do you mean like, just one SoC for my 'slaves' and my client (or master) pipeline? Also I'm not sure I want Ble (low energy) for the box to client comm, in fact I want a "fat" fast Bt connection on that side, and the low-energy only to the nodes / slaves.

[Elfving]

Hello again!

v01d said:

this would be some kind of round-robin, one at a time? 

Exactly. Of course there might be gains in speed and throughput from using several, but that would add to the cost and complexity.

v01d said:

Is there some kind of tech spec or a simulator tool to know how fast one can poll / comm with those nodes using just one Nordic chip which has both Zigbee & Bt ? 

Not that I can think of unfortunately. I would recommend you to test it, and see if it works well enough for what you are trying to do. The documentation on MPSL and Zigbee should give you an idea though.

v01d said:

Is there a significant time spent when you switch between Bt and Zigbee modes (or profiles, whatever is suitable terminology here), to poll the nodes ?

Not significant, no. The protocols are already initialized, the CPU only needs to change the radio peripheral and set the frequency. Though that is something CPU needs to do, so it is hard to give you a time estimate for this, as it depends on the CPU usage.

There is more info on the timeslots, scheduling, etc in the documentation. There is also a diagram showing en entire time slot session.

v01d said:

Do you mean like, just one SoC for my 'slaves' and my client (or master) pipeline?

Here I am a little uncertain about what you mean.

I am talking about one SoC for your comm box master, not the sensor slaves. The communication with the comm box client can also be handled by the same SoC. Though it is hard to say anything for certain about what would pay off. I would recommend you to rather start with a DK with the SoC of your choosing from this table and see if you can get the throughput you need.

Regards,

Elfving

[v01d]

Elfving said:

Here I am a little uncertain about what you mean.

I think I meant what you suggesgt :)  Just one Nordic Soc in my box, not 2 as I thought.

I thought this , might be way :

[ slaves,  with Zb or Btle . ] <--- -> [ my box iface with Btle & Zb ;  2nd iface Bt full speed ] <--->  [ external client ]

But you seems, suggesting just having One module / one interface there. Am I wrong?

[Elfving]

Sorry about the delay, I've been away for two weeks. 

Yes, I am suggesting only using one SoC for both the communication with the slaves, and with the external unit. Have you decided on getting a DK?

Regards,

Elfving

[v01d]

Elfving : hello  & hope the break was good.

No, I haven't decided, could you advise me on the exact DK to get? I will just get one same as you would suggest from local supplier - Mouser.

[Elfving]

Either of the ones from the list I provided. Maybe a nRF52840 would be good, as the nRF5340 might add to the complexity. Either way, I would recommend you to have a look at their differences and specs. 

I mainly just wanted to make sure that you try this out with a DK before trying to make a PCB.

Regards,

Elfving