LWM2M with ESP32 using Eclipse Leshan

Objective

To implement LWM2M communication on an ESP32 using the Eclipse Leshan client, enabling efficient device management and remote monitoring through an LWM2M server.

Hardware Requirements

ESP32 Development Board
Wi-Fi Network
PC/Laptop for running Leshan Server
Optional IoT Sensors (e.g., DHT11, Temperature, Humidity)

Step 1: Leshan Server Setup

Clone the Eclipse Leshan GitHub repository.
Follow the Leshan Server Setup Guide for installation on a local or cloud server.
Run the Leshan server (default port: 5683).

Step 2: ESP32 Client Setup

Environment: Use Arduino IDE or PlatformIO to set up your ESP32 development environment.

Required Libraries

WiFi.h
CoAP.h (for LWM2M protocol)

Server Configuration

1const char* serverAddress = "your_leshan_server_ip";
2const int serverPort = 5683;

Step 3: LWM2M Client Code

WiFi Setup

1const char* ssid = "your_wifi_ssid";
2const char* password = "your_wifi_password";
3
4void setup() {
5  Serial.begin(115200);
6  WiFi.begin(ssid, password);
7  while (WiFi.status() != WL_CONNECTED) {
8    delay(1000);
9    Serial.println("Connecting to WiFi...");
10  }
11  Serial.println("Connected to WiFi");
12}

Basic Client Code

1#include <WiFi.h>
2#include <CoAP.h>
3
4const char* serverAddress = "your_leshan_server_ip";
5const int serverPort = 5683;
6const char* ssid = "your_wifi_ssid";
7const char* password = "your_wifi_password";
8
9void setup() {
10  Serial.begin(115200);
11  WiFi.begin(ssid, password);
12  while (WiFi.status() != WL_CONNECTED) {
13    delay(1000);
14    Serial.println("Connecting to WiFi...");
15  }
16  Serial.println("Connected to WiFi");
17
18  lwm2m_client_init();
19  lwm2m_set_server_address(serverAddress, serverPort);
20}
21
22void loop() {
23  lwm2m_send_data();
24  delay(10000);
25}

Define Resources

1#include <lwm2m.h>
2
3lwm2m_resource_t temperature_resource;
4float temperature_value = 25.0;
5
6void setup() {
7  lwm2m_init();
8  lwm2m_register_resource(&temperature_resource, 3303, 0, "Temperature", &temperature_value);
9}
10
11void loop() {
12  lwm2m_update_resource(&temperature_resource);
13  delay(5000);
14}

Step 4: LWM2M Communication Functions

Client Init

1void lwm2m_client_init() {
2  lwm2m_client_init(client);
3  lwm2m_set_server_address(client, serverAddress, serverPort);
4}

Resource Handling

1void lwm2m_update_resource(lwm2m_resource_t* resource) {
2  lwm2m_send_data(client, resource);
3}

Step 5: Monitoring

Once ESP32 is running, the device will register with Leshan server and can be managed via the Leshan web UI or any CoAP client.

Step 6: Testing

Verify that ESP32 successfully sends data to the server. Check that the resources like temperature are visible and retrievable via UI or CoAP queries.

Step 7: Security Configuration

Objective: Use DTLS for secure communication between ESP32 and Leshan server.

1lwm2m_set_security_mode(client, LWM2M_SECURITY_DTLS);
2lwm2m_set_dtls_certificates(client, "client_cert.pem", "client_key.pem", "server_cert.pem");