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    IoT Platform:Connect a device to IoT Platform and submit data

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    IoT Platform:Connect a device to IoT Platform and submit data

    Last Updated:Jun 16, 2026

    After you obtain a device certificate (ProductKey, DeviceName, and DeviceSecret), connect the device to an Enterprise Edition instance over MQTT. Use Link SDK for C to configure a simulated device and submit data.

    Prerequisites

    A product and a device are created. For more information, see Create a product and device.

    Before you begin

    All operations in this example use regular user permissions. To perform operations that require administrator permissions, run the sudo command.

    Prepare a development environment

    • Link SDK for C is used on Linux in this example. We recommend 64-bit Ubuntu 20.04 for compiling the SDK.

      An Elastic Compute Service (ECS) instance serves as the simulated device that connects to IoT Platform and submits data. For more information about how to purchase an ECS instance, see Create an instance.

    • The following software is required to develop and compile the SDK:

      make (version 4.1 or later) and gcc (version 5.4.0 or later)

      Run the following command to install the software:

      sudo apt-get install -y build-essential make gcc

    Obtain Link SDK for C

    Download the LinK SDK for C V4.x compression package and change the name of the package to LinkSDK.zip.

    Develop a sample program for the device

    Note

    This example uses a Thing Specification Language (TSL)-specific topic to submit data. You can also use custom topics to send data to devices. For more information, see Use custom topics.

    1. Log on to the ECS instance. For more information, see Remote connection methods for ECS instances.

    2. Run the following command to install GCC and Make: 

      sudo apt-get install -y build-essential make gcc

    3. Upload the LinkSDK.zip file and decompress the file.

      1. Upload on-premises files to the ECS instance.

      2. Run the following commands to install unzip: 

        apt update
apt install unzip

      3. Go to the directory in which the LinkSDK.zip file resides and run the following command to decompress the file: 

        unzip LinkSDK.zip

    4. Go to the /LinkSDK/demos directory, open the data_model_basic_demo.c file, and configure the device verification parameters.

      /* TODO: Replace the following variables with the information about your device certificate. */
char *product_key       = "a2******";
char *device_name       = "Device1";
char *device_secret     = "8c684ef*************";

......

char  *mqtt_host = "iot-cn-******.mqtt.iothub.aliyuncs.com";

      Parameter

      Example

      Description

      product_key

      a2******

      The device certificate that is used for verification. This certificate is saved on your on-premises server after you add the device.

      You can also view the device certificate on the Device Details page in the IoT Platform console.

      device_name

      Device1

      device_secret

      8c684ef*************

      mqtt_host

      iot-cn-******.mqtt.iothub.aliyuncs.com

      The MQTT endpoint. In the upper-right corner of the Instance Details page, click View Development Configurations. In the Development Configurations panel, view the endpoint.

      For more information about instances, see Manage instance endpoints.

    5. Modify the following sample code to submit temperature and humidity data: 

          /* The main thread goes to sleep. */
    while (1) {
        /* TODO: The following sample code shows how to submit properties and events. You can uncomment the sample code to view the result. */
        demo_send_property_post(dm_handle, "{\"temperature\": 30,\"humidity\": 42}");
        ......

        sleep(5);
    }

    6. Modify the following sample code to subscribe to a custom topic. The custom topic is used to receive commands from IoT Platform. 

      aiot_mqtt_sub(mqtt_handle, "/a2******/Device1/user/get", NULL, 1, NULL);

    7. In the /LinkSDK root directory, run the following commands to compile the sample program: 

      make clean
make

      The generated data-model-basic-demo file is stored in the ./output directory.

    8. Run the following command to execute the sample program: 

      ./output/data-model-basic-demo

      If the sample program runs as expected, the following logs are generated:

      [1695199326.066][LK-0313] MQTT user calls aiot_mqtt_connect api, connect
[1695199326.066][LK-032A] mqtt host: iot-cn-******.mqtt.iothub.aliyuncs.com
[1695199326.066][LK-0317] user name: Device1&a2******
establish tcp connection with server(host='iot-cn-******.mqtt.iothub.aliyuncs.com', port=[443])
success to establish tcp, fd=3
local port: 36030
[1695199326.077][LK-1000] establish mbedtls connection with server(host='iot-cn-******.mqtt.iothub.aliyuncs.com', port=[443])
[1695199326.122][LK-1000] success to establish mbedtls connection, (cost 45382 bytes in total, max used 48350 bytes)
[1695199326.166][LK-0313] MQTT connect success in 92 ms
AIOT_MQTTEVT_CONNECT
[1695199326.166][LK-0309] sub: /a2******/Device1/user/get
[1695199326.166][LK-0309] pub: /sys/a2******/Device1/thing/event/property/post

[LK-030A] > 7B 22 69 64 22 3A 22 31  22 2C 22 76 65 72 73 69 | {"id":"1","versi
[LK-030A] > 6F 6E 22 3A 22 31 2E 30  22 2C 22 70 61 72 61 6D | on":"1.0","param
[LK-030A] > 73 22 3A 7B 22 74 65 6D  70 65 72 61 74 75 72 65 | s":{"temperature
[LK-030A] > 22 3A 20 33 30 2C 22 68  75 6D 69 64 69 74 79 22 | ": 30,"humidity"
[LK-030A] > 3A 20 34 32 7D 2C 22 73  79 73 22 3A 7B 22 61 63 | : 42},"sys":{"ac
[LK-030A] > 6B 22 3A 31 7D 7D                                | k":1}}          

[1695199326.244][LK-0309] pub: /sys/a2******/Device1/thing/event/property/post_reply

[LK-030A] < 7B 22 63 6F 64 65 22 3A  32 30 30 2C 22 64 61 74 | {"code":200,"dat
[LK-030A] < 61 22 3A 7B 7D 2C 22 69  64 22 3A 22 31 22 2C 22 | a":{},"id":"1","
[LK-030A] < 6D 65 73 73 61 67 65 22  3A 22 73 75 63 63 65 73 | message":"succes
[LK-030A] < 73 22 2C 22 6D 65 74 68  6F 64 22 3A 22 74 68 69 | s","method":"thi
[LK-030A] < 6E 67 2E 65 76 65 6E 74  2E 70 72 6F 70 65 72 74 | ng.event.propert
[LK-030A] < 79 2E 70 6F 73 74 22 2C  22 76 65 72 73 69 6F 6E | y.post","version
[LK-030A] < 22 3A 22 31 2E 30 22 7D                          | ":"1.0"}        

[1695199326.244][LK-0A08] DM recv generic reply
demo_dm_recv_handler, type = 0
demo_dm_recv_generic_reply msg_id = 1, code = 200, data = {}, message = success

    9. Log on to the IoT Platform console, find and click the target Enterprise Edition instance to go to the Instance Details page, and then view the device status.

      1. In the left-side navigation pane, choose Devices > Devices. On the Devices page, find Device1 and view the device status. The value Online in the Device Status column indicates that the device is connected to IoT Platform.

        image.png

      2. Click View in the Actions column. On the device details page, click TSL Data. On the TSL Data tab, click Status. On the Status tab, view the device status.

        The temperature and humidity data are submitted to IoT Platform by using the sample code in the data_model_basic_demo.c file.

        image.png

    What to do next

    Forward data to OTS