Connect a device to IoT Platform with the device-side Link SDK - IoT Platform

Use the data_model_basic_demo sample program to simulate a street lamp device and connect it to IoT Platform through the C SDK.

Important notes

The steps in this topic are performed by a regular user. If you encounter an operation that requires administrative permission, run the command with sudo.

Prepare the development environment

The device-side C SDK runs on Linux. Compile it in a 64-bit Ubuntu 16.04 environment.
Required software:

make 4.1 or later, gcc 5.4.0 or later.

Install command:
```
sudo apt-get install -y build-essential make gcc
```

Procedure

Download the C SDK for devices: C SDK 4.x.

Unzip the C SDK file and modify the device certificate information.

Download data_model_basic_demo.c and use it to replace the file in \LinkSDK\demos. Update the following parameters:

char *product_key       = "a2***";
char *device_name       = "device1";
char *device_secret     = "8c684ef***";
...
...
char  *mqtt_host = "a2***.iot-as-mqtt.cn-shanghai.aliyuncs.com";

Parameter	Example	Description
mqtt_host	New public instances:`iot-cn-*.mqtt.iothub.aliyuncs.com` Old public instances:`a2*.iot-as-mqtt.cn-shanghai.aliyuncs.com`	The MQTT ingest endpoint for the device. New public instances: On the Instance Details page, click View Development Configurations. The endpoint appears on the Development Configurations panel. Old public instances: The endpoint format is`${YourProductKey}.iot-as-mqtt.${YourRegionId}.aliyuncs.com`. View instance endpoints.
product_key	`a2***`	The device certificate saved when you added the device. You can also view the certificate on the Device Details page in the IoT Platform console. Obtain a device certificate.
device_name	`device1`
device_secret	`8c684ef***`

On the Linux virtual machine, install the required software.
```
sudo apt-get install -y build-essential make gcc
```
Upload the modified LinkSDK directory to your Linux virtual machine.
In the SDK root directory /LinkSDK, run the make command to compile the sample program.
```
make clean
make
```
The compiled binary data-model-basic-demo is in ./output.
Run the sample program.
```
./output/data-model-basic-demo
```
Expected output:
In the IoT Platform console, go to the Public Instance page. Verify the device status.
- Choose Device Management > Devices. If the device status is Online, the device is connected to IoT Platform.
- Click View in the Actions column. On the Device Details page, click the TSL Data tab and then Running Status.
  
  The data_model_basic_demo.c sample reports the operating current value.

What to do next

You can now subscribe to device messages from the server.