coap-demo

A CoAP demo for nRF52 DK

This demo contains two applications: coap-server and coap-client which are similar to [Coap Observable Server] and [Coap Observer Client] examples provided by the nRF5 IoT SDK.

Note that before any CoAP requests can be made you’ll need to configure an IPv6 connection to the device and assign a routable IPv6 address.

For details how to do this please refer to sections ‘Establishing an IPv6 connection’ and ‘Distributing routable IPv6 prefix’ in platform/nrf52dk/README-BLE-6LoWPAN.md.

CoAP Server

The server exposes the following resources:

host
|-- .well-known
|   `-- core
`-- lights
    `-- led3

The state of LED 3 can be set and queried via CoAP through the observable resource lights/led3. Current state of LED 3 is returned as a text string in the payload. The value 0 means that LED 3 is off, 1 otherwise.

Button 1 can be used to toggle state of the LED 3. This will cause a notification to be sent to any subscriber observing lights/led3. The state of the resource can also be changed by using POST/PUT to the resource with desired state encoded as a text in the payload. Send 1 to switch on and 0 to switch off.

In order to compile and flash the CoAP server to a DK execute:

make TARGET=nrf52dk coap-server.flash

Note, if you haven’t previously used a given device with Contiki it is recommended to erase the device and flash SoftDevice before flashing CoAP application, i.e.,

make TARGET=nrf52dk erase
make TARGET=nrf52dk softdevice.flash

Please refer to the Testing and Python Example sections of [Coap Observable Server] tutorial for detailed description how to query the Coap Server using a PC.

CoAP Client

CoAP client compliments the CoAP server application. When Button 1 on the DK is pressed the the client subscribes to lights/led3 resource. If successful the LED 4 will blink briefly. From this moment any change of the lights/led3 resource will be automatically reflected by the client’s LED 3.

Note that the client must know the server’s IPv6 address. The address is specified as a make variable during compliation.

In order to compile and flash the CoAP client to DK execute:

make TARGET=nrf52dk SERVER_IPV6_ADDR=<full-ip6-address> coap-client.flash

Note, that you can use NRF52_JLINK_SN=<SN> to select a particular devkit in a case when you have more than one boards connected to PC. Please refer to platform/README.md for details.

Please refer to the Testing and Python Server Example sections of [Coap Observer Client] tutorial for detailed description how to use CoAP client demo with a PC.

Resources

[Coap Observable Server] http://developer.nordicsemi.com/nRF5_IoT_SDK/doc/0.9.0/html/a00054.html [Coap Observer Client] http://developer.nordicsemi.com/nRF5_IoT_SDK/doc/0.9.0/html/a00051.html