Hi,
I am trying to following the instructions at: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.iotsdk.v0.9.0%2Fiot_sdk_user_guides_java_coaps.html
but the directory paths of Californium has deviated quite a bit since this was published. Do you have some updated instructions on how to use Californium with your IoT examples?
Thanks very much.
Last weekend I was also able to spend some time into that.
The most challenging task seems to find a linux distribution with working bluetooth_6lowpan out of the box. On a Ubuntu 18.04 PC it works, for the Raspi OS it seems to disconnect after 30-40s.
Using such "out-of-the-box" bluetooth_6lowpan kernels (newer than 4.12) requires then to compile the iot examples using BLE_6LOWPAN_LEGACY_MODE=0 in the sdk_config.h.
After that it is easy as:
sudo -s (enter su shell, execute the following commands in that shell)
modprobe bluetooth_6lowpan
hcitool lescan
echo "connect 00:AA:BB:CC:DD:EE 1" > /sys/kernel/debug/bluetooth/6lowpan_control
That's it, your device is connected and may be ping6ed. The ping6 response contains the IPv6 address of the device and the host. If you don't get a ping6 response from the device but only from the host itself, check, if the BLE_6LOWPAN_LEGACY_MODE is really set to 0.
To use the iot dtls coap-server example, download the prebuild cf-client from Eclipse Releases - cf-client-2.4.1.jar
With that IPv6 address from the ping6 just start the client on the same host running the bluetooth_6lowpan using:
java -jar cf-client-2.4.1.jar --identity Client_identity --secret secretPSK 'coaps://[fe80::aa:bbff:fecc:ddee%bt0]/lights/led3' --method PUT --payload 2
the out should be something as:
==[ CoAP Request ]=============================================
MID : 24288
Token : 1CDF1DDD4467DAD3
Type : CON
Method : 0.03 - PUT
Options: {"Uri-Path":["lights","led3"]}
Payload: 1 Bytes
---------------------------------------------------------------
2
===============================================================
>>> DTLS([fe80:0:0:0:39:d5ff:fe9e:f2eb%bt0]:5684,ID:0E5376F5E6)
>>> TLS_PSK_WITH_AES_256_CCM
>>> PreSharedKey Identity [identity: Client_identity]
Time elapsed (ms): 1352
==[ CoAP Response ]============================================
MID : 24288
Token : 1CDF1DDD4467DAD3
Type : ACK
Status : 2.04 - CHANGED
Options: {}
RTT : 1352 ms
Payload: 0 Bytes
===============================================================
and the LED 3 is switching on. That takes the 1,3 s (no 3 minutes :-) ).
Unfortunately, it's not possible to reconnect the device's server again without disconnect the ble connection. So, if you want to play more, try out the Eclipse Releases - cf-browser-2.4.1. The browser uses javaFX, which is required to be installed ahead. Start the cf-browser similar as cf-client using:
java --module-path /usr/share/openjfx/lib --add-modules javafx.controls,javafx.fxml -jar cf-browser-2.4.1.jar --identity Client_identity --secret secretPSK 'coaps://[fe80::39:d5ff:fe9e:f2eb%bt0]'
(that assumes openjdk java 11 on ubuntu 18.04 using openjfx)
The UI should be easy to use. Press DISCOVER to see the resources of the devices coap-server. Select the resource lights/led3 on the resources tree on the left. select a GET to see the state, or type a 2 and use PUT to toggle the LED.
