STM32F103单片机怎么用ESP8266实现手机WIFI无线APP控灯亮灭及亮度

实现STM32F103单片机通过ESP8266实现手机WIFI无线APP控灯亮灭及亮度的方法如下：

1. 硬件连接

将ESP8266模块的TXD和RXD分别连接到STM32F103单片机的USART1的RXD和TXD上，将ESP8266的VCC和GND分别连接到单片机的3.3V和GND上。

2. 软件实现

(1) 初始化ESP8266模块

使用单片机的USART1与ESP8266模块通信，发送AT指令初始化ESP8266模块，如下所示：

void esp8266_init(void)
{
    USART_SendString(USART1,"AT+RST\r\n"); //重启ESP8266
    delay_ms(500); 
    USART_SendString(USART1,"AT+CWMODE=1\r\n"); //设置WIFI模式为STA
    delay_ms(500);
    USART_SendString(USART1,"AT+CIPMUX=0\r\n"); //设置单连接模式
    delay_ms(500);
    USART_SendString(USART1,"AT+CIPSTART=\"TCP\",\"192.168.1.100\",8080\r\n"); //连接APP服务器
    delay_ms(500);
}

(2) 实现TCP/IP协议栈

使用lwIP协议栈实现TCP连接和数据传输，通过AT指令实现与ESP8266模块的通信，如下所示：

void lwip_demo(void)
{
    struct netconn *conn;
    struct netbuf *buf;
    char *data;
    uint16_t len;

    //创建TCP连接
    conn = netconn_new(NETCONN_TCP);
    netconn_connect(conn, IP_ADDR_ANY, 8080);

    //循环接收数据
    while (1) {
        if (netconn_recv(conn, &buf) == ERR_OK) {
            netbuf_data(buf, (void**)&data, &len);
            //处理接收到的数据
            //...
            netbuf_delete(buf);
        }
    }
}

(3) 实现控制逻辑

通过数据解析实现控制逻辑，将APP发送的控制指令解析成PWM输出和开关控制，如下所示：

void control_logic(char *data, uint16_t len)
{
    //解析JSON数据
    cJSON *root = cJSON_Parse(data);
    cJSON *cmd = cJSON_GetObjectItem(root, "cmd");
    cJSON *param = cJSON_GetObjectItem(root, "param");
    if (strcmp(cmd->valuestring, "switch") == 0) {
        //控制灯的开关
        if (strcmp(param->valuestring, "on") == 0) {
            GPIO_SetBits(GPIOA, GPIO_Pin_0);
        } else {
            GPIO_ResetBits(GPIOA, GPIO_Pin_0);
        }
    } else if (strcmp(cmd->valuestring, "brightness") == 0) {
        //控制灯的亮度
        uint8_t brightness = param->valueint;
        TIM_SetCompare1(TIM2, brightness*10);
    }
    cJSON_Delete(root);
}

3. 编写APP代码

在APP中实现控制界面，通过HTTP协议向ESP8266发送控制指令，如下所示：

public class MainActivity extends AppCompatActivity {

    private String host = "192.168.1.100";
    private int port = 8080;

    private Button btnOn, btnOff, btnBright;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btnOn = findViewById(R.id.btnOn);
        btnOff = findViewById(R.id.btnOff);
        btnBright = findViewById(R.id.btnBright);

        btnOn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String url = "http://" + host + ":" + port + "/?cmd=switch&param=on";
                new HttpTask().execute(url);
            }
        });

        btnOff.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String url = "http://" + host + ":" + port + "/?cmd=switch&param=off";
                new HttpTask().execute(url);
            }
        });

        btnBright.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String url = "http://" + host + ":" + port + "/?cmd=brightness&param=" + 50;
                new HttpTask().execute(url);
            }
        });
    }

    private class HttpTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... urls) {
            try {
                URL url = new URL(urls[0]);
                HttpURLConnection conn = (HttpURLConnection)url.openConnection();
                conn.setRequestMethod("GET");
                conn.setConnectTimeout(5000);
                conn.setReadTimeout(5000);
                conn.connect();

                if (conn.getResponseCode() == 200) {
                    InputStream is = conn.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                    StringBuilder sb = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        sb.append(line);
                    }
                    return sb.toString();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }
    }
}

需要注意的是，以上代码仅为示例代码，实现功能需根据具体需求进行修改和完善。