Lwm2M Object

In this tutorial, you'll learn about LwM2M Custom Object Not Accessible. We cover key concepts, practical examples, and best practices.

The Problem

A custom LwM2M object registered by the client is not visible to the server.

Quick Fix

Wrong

# Object ID not registered with server

Server cannot access the custom object — returns 4.04 Not Found.

Right

# Object definition (JSON)
{
  'id': 32768,  # Vendor-specific range (32768-65535)
  'name': 'My Sensor',
  'multiple': false,
  'instances': 1,
  'resources': [
    {
      'id': 0,
      'name': 'Temperature',
      'operations': 'R',
      'type': 'float',
      'range': [-40, 125]
    },
    {
      'id': 1,
      'name': 'Unit',
      'operations': 'RW',
      'type': 'string'
    }
  ]
}

# Client installation (Anjay)
#include <anjay/anjay.h>

static int temp_read(anjay_t *anjay,
  const anjay_rid_t *rid, anjay_output_ctx_t *ctx) {
  anjay_ret_float(ctx, 25.5);
  return 0;
}

const anjay_dm_object_def_t *my_obj =
  anjay_dm_object_def_create(32768, &def);

anjay_register_object(anjay, my_obj);

Server can read the custom object (32768/0/0 = 25.5).

Prevention

Object IDs: 0-2047 = OMA standard, 2048-32767 = production, 32768-65535 = vendor-specific. Register objects via an IPSO XML or JSON definition. Server must also know the object definition. LwM2M object structure: Object > Instance > Resource. Instance 0 is usually the default.

DodaTech engineers apply these same patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro for production IoT reliability.

FAQ