what is the maximum number of device(nrf52832) can connect to ipv6 gatway (raspberry pi 3) using BLE ?

[Dan_sh]

Hello

How many BLE devices(nrf52832 DK) can connect to raspberry pi 3 (as a 6lowpan gatway)  over 6lowpan BLE? 

[Edvin]

Hello,

This is a bit out of our control. It is defined by the gateway, and not the nRF.

It is the HCI device on the raspberry that decides this. Typically, the dongle or the BLE chip has a maximum number, which will cap the number of connections. Linux in itself doesn't have a limitation. It is often more 8 or more, but it depends on the producer.

Best regards,

Edvin

[Dan_sh]

Dear Edvin,

Thank you for your reply.

So what kind of BLE USB dongle or gateway you suggest to achieve the maximum number of node.

Each node i want to use in 6lowpan ,do this :

Send temperature and humidity and control 2 relay.With this scenario, is it possible to connect 10 nodes to raspberry pi(as gateway)?if not how many nodes can connect? and access all of them at same time .

Thank you

[Edvin]

I can't recommend any particular dongle. Depending on what Raspberry Pi version you have (3 B+), it can use the on board radio to connect to BLE devices. You have to do some testing. This also depends on the connection interval on each connection. Make sure that it is large enough to have time for 10 devices (if that is what you intend to use). A BLE event takes a couple of ms, depending on how much data you send. If you have the lowest possible connection interval (7.5ms), there is only time for 2-3 connections. If you raise the connection interval to something like 100ms, that shouldn't be a problem.

You have to read up on what number of connections the different dongles support. We don't produce any HCI dongles, which is what you are looking for. I don't believe that the Raspberry has a limit of connections in the OS. It is dependent on the chip.

Best regards,

Edvin