How to remote control nRF52840 LED's on/off through openThread network

[chunwang]

Topology:

Raspberry Pi A                                          Raspberry Pi B

     |(USB connect)                                             |(USB connect)

nRF52840 dongle A      )))) Thread (((( nRF52840 dongle B

Software:

nrf52840-dongle: ot-rcp.hex

Raspberry Pi: Linux with OTBR.

Status:

Thread network created success, can ping pass from Raspberry Pi A(leader) to Raspberry Pi B(router).

Question:

How to control nRF52840 dongle B's LED on/off in Raspberry Pi A through thread network?  Use CoAP? or other?

[Jørgen Holmefjord]

Hi,

In the RCP configuration, the OpenThread Stack and application does not run on the nRF52840 Dongle, but on the host processor (Raspberry Pi in your case). The RCP itself is not a node in the Thread network, it is only a radio interface for the host processor to send and receive packets. The RCP is not able to process the IP or application packets, and it would therefore not be possible to control the LED of the dongle directly from another Thread node. 

The only alternative I can think of, is for the host to control the GPIO of the Dongle, on reception of a specific packet from the other Thread node, through the "diag gpio" commands. In OTBR, you should be able to run DIAG commands from OTBR like this if wpantund is installed/enabled: "sudo wpanctl mfg gpio".

Best regards,
Jørgen

[Jørgen Holmefjord]

The GPIO connections for the nRF52840 Dongle can be found in the Buttons and LEDs documentation.

The GPIO specifications for nRF52840 can be found in the GPIO — General purpose input/output section in the product specifications.