Generic Sensor lwM2M-Client

[JVKran]

Hi there!

I'm using the nRF Connect SDK with the VScode extension for developing an application for the nRF9160DK. I've taken the lwm2m_client sample as base and rewrote it to a class since that suits the rest of our codebase better.

Now, I'd like to add a generic sensor to the client. Unforutnately, I can't get it to work. The 'init' method is called at the same time of lwm2m_init_location, lwm2m_init_firmware, etc. set_value is used in another dummy thread that's started after a connection has been established. Oh, and I've used this tutorial for defining the custom generic sensor object.

struct float32_value generic_sensor_c::sensor_value = { 1, 0 };

void *generic_sensor_c::read_cb(uint16_t obj_inst_id, uint16_t res_id, uint16_t res_inst_id, size_t *data_len){
    if (obj_inst_id != instance) {
       *data_len = 0;
        return NULL;
    }

    ++sensor_value.val2;

    lwm2m_engine_set_float32((char*)"3300/0/5700", &sensor_value);
    *data_len = sizeof(sensor_value);
    return &sensor_value;
}

void generic_sensor_c::init(){
    lwm2m_engine_create_obj_inst((char*)"3300/0");
    lwm2m_engine_register_read_callback((char*)"3300/0/5700", read_cb);
}

void generic_sensor_c::set_value(const int32_t new_value){
    sensor_value.val2 = new_value;
    lwm2m_engine_set_float32((char*)"3300/0/5700", &sensor_value);
}

Obviously, I must be overseeing something.

Kind regards,

Jochem

[Charlie]

Hi Jochem,

I am not very familiar with C++, but I have tried to add generic sensor objects to the original nRF9160: LwM2M Client sample by following the tutorial, and it can work properly.

You can find the following attachment and compare it with the original sample with "git diff". Hope it can bring some inspiration to your issue.

ncs171_lwm2m_client_generic_sensor.zip

Best regard,

Charlie

[JVKran]

Hi Charlie,

Thanks for responding. Interesting. I've found out where the problem lies.

It's the `lwm2m_engine_create_obj_inst("3300/0");` call that returns `<err> net_lwm2m_engine: obj instance 3300/0 not found`... 

Still makes me wonder what could be the problem. Do you have any idea as to what the problem could be? Otherwise I guess I'll just have to rewrite the implementation.

Kind regards,

Jochem

[JVKran]

Turned out; taking your time is key... Overlooked one teeny tiny little detail. The configuration variable in the prj.cnf... Solved now, sorry for having wasted your time.