OpenThread CoAP example

[Danny]

Hello, I'm using the openthread border router (wpantund) along with another end device running the simple_coap_server example that exposes a "light" resource.

I have connectivity to the device and using the firefox copper plugin I can do a "PUT" to: "coap://[IPV6 ADDRESS]/light"

and get back a "2.04 Changed". So it appears I have good connectivity but when I try to pass in a command to the resource I get a 4.04 response. The URI's I have tried are: "coap://[IPV6 ADDRESS]/light/light_on" and "coap://[IPV6 ADDRESS]/light/light_off"

Neither of these change the LED and I get a 4.04 response.

Any ideas what might be happening?

Setup: Raspberry Pi3 running openthread border router --> 52840 dev kit (running ot-ncp-ftd) Another 52840 dev kit running the thread sdk version 10 Thread Simple CoAP Server

[Lukasz Duda]

Hello Danny,

Thank you for trying out nRF5 SDK for Thread!

The particular example that you used (simple_coap_server) exposes only two resources:

• /light
• /provisioning

You received 4.04 responses (Not Found) for /light/light_on or /light/light_off resources since they do not exist.

Simple coap server controls its led using payload of PUT request on /light resource. Accepted payload is:

• 0 (Turn off the led)
• 1 (Turn on the led)
• 2 (Toggle the led)

Note that you can specify payload also in the copper plugin: Payload section -> Outgoing tab. The difficult part is that Cooper plugin allows only to send ASCII string. However the example expects binary 0, 1 or 2, not character '0' which is binary 48. So i believe the easiest solution to use cooper would be to change light_command_t enum in the main.c to:

typedef enum
{
    LIGHT_OFF = '0', // originally was 0, (0 is different than ASCII '0' - which is 48)
    LIGHT_ON,
    LIGHT_TOGGLE
} light_command_t;

Of course it is possible to add a new resources: /light/light_on and /light/light_off by modyfing SDK's example.

We will try to change expected commands value to accept also ASCII characters in upcoming releases to make Cooper plugin easier to use.

[Danny]

Thanks Lukasz!, that totally solved it. Time to start adding some new resources!