物联网设备通信协议开发指南：从选型到落地的实操技巧

import paho.mqtt.client as mqtt
import random
import time

def on_connect(client, userdata, flags, rc):
    print(f"连接成功，返回码：{rc}")
    client.subscribe("iot/device/control", qos=1)  # 订阅命令主题

def on_message(client, userdata, msg):
    print(f"收到命令：{msg.payload.decode()}")
    if msg.payload.decode() == "turn_on_light":
        print("执行开灯操作")

# 初始化客户端
client = mqtt.Client(client_id=f"device_{random.randint(1000, 9999)}")
client.on_connect = on_connect
client.on_message = on_message
client.username_pw_set("iot_user", "iot_pass")  # 可选：用户名密码认证
client.connect("broker.emqx.io", 1883, 60)  # 连接公共EMQX Broker

client.loop_start()  # 启动循环

# 模拟温度上报（每5秒一次）
while True:
    temp = round(random.uniform(20, 30), 2)
    client.publish("iot/sensor/temp", f"{{"temp":{temp}}}", qos=1)
    print(f"上报温度：{temp}℃")
    time.sleep(5)

#include <stdio.h>
#include <coap3/coap.h>

// 响应回调函数
static void response_handler(coap_session_t *session, const coap_pdu_t *sent, const coap_pdu_t *received, const coap_mid_t mid) {
    if (!received) { printf("请求超时
"); return; }
    if (coap_pdu_get_code(received) == COAP_RESPONSE_CONTENT) {
        size_t len;
        const uint8_t *payload = coap_pdu_get_payload(received, &len);
        printf("温度：%.*s℃
", (int)len, payload);
    }
}

int main() {
    coap_context_t *ctx = coap_new_context(NULL);
    coap_address_t server_addr;
    coap_address_init(&server_addr);
    server_addr.addr.sa_family = AF_INET;
    inet_pton(AF_INET, "127.0.0.1", &((struct sockaddr_in *)&server_addr.addr)->sin_addr);
    ((struct sockaddr_in *)&server_addr.addr)->sin_port = htons(5683);  // CoAP默认端口

    coap_session_t *session = coap_new_client_session(ctx, NULL, &server_addr, COAP_PROTO_UDP);
    coap_pdu_t *pdu = coap_pdu_create(COAP_MESSAGE_CON, COAP_REQUEST_GET, coap_new_message_id(session), coap_session_get_mtu(session));

    // 设置URI路径（/sensor/temp）
    coap_uri_t uri;
    coap_uri_parse("coap://127.0.0.1/sensor/temp", &uri);
    coap_add_option(pdu, COAP_OPTION_URI_PATH, uri.path.length, uri.path.s);

    // 订阅观察模式
    uint8_t observe[] = {0};
    coap_add_option(pdu, COAP_OPTION_OBSERVE, sizeof(observe), observe);

    coap_register_response_handler(session, response_handler);
    coap_send(session, pdu);

    printf("等待温度更新...
");
    while (1) coap_run_once(ctx, 1000);  // 每秒运行一次事件循环

    coap_session_release(session);
    coap_free_context(ctx);
    return 0;
}

#include <LoRa.h>

// LoRa模块引脚（根据硬件调整）
const int ssPin = 10, rstPin = 9, dio0Pin = 2;
// LoRaWAN参数（从ChirpStack获取）
const char* devEui = "0011223344556677";
const char* appEui = "8877665544332211";
const char* appKey = "0123456789ABCDEF0123456789ABCDEF";

void setup() {
  Serial.begin(9600);
  LoRa.setPins(ssPin, rstPin, dio0Pin);
  if (!LoRa.begin(868E6)) {  // EU868频段
    while (1) Serial.println("LoRa初始化失败！");
  }
  LoRa.setSpreadingFactor(7);  // SF7，平衡距离和速率
  joinLoRaWAN();  // 加入网络
}

void loop() {
  // 每30秒上传温度
  static unsigned long lastSend = 0;
  if (millis() - lastSend > 30000) {
    lastSend = millis();
    int temp = analogRead(A0);  // 读取模拟传感器
    sendData(temp);
    Serial.print("上传温度："); Serial.println(temp);
  }
}

// 发送Join请求，加入LoRaWAN
void joinLoRaWAN() {
  Serial.println("发送Join请求...");
  LoRa.beginPacket();
  LoRa.write(0x00);  // MHDR：Join Request
  LoRa.write((const uint8_t*)devEui, 8);
  LoRa.write((const uint8_t*)appEui, 8);
  LoRa.write((const uint8_t*)appKey, 16);
  LoRa.endPacket();
  // 等待Join Accept（Class A接收窗口）
  LoRa.receive(); delay(1000);  // Rx1窗口
  LoRa.receive(); delay(2000);  // Rx2窗口
}

// 上传数据到LoRaWAN
void sendData(int data) {
  LoRa.beginPacket();
  LoRa.write(0x40);  // MHDR：Unconfirmed Data Up（非确认上行）
  LoRa.write(0x01);  // DevAddr（设备地址）
  LoRa.write(0x00);  // FCtrl
  LoRa.write(0x00);  // FCnt
  LoRa.write(0x01);  // FPort
  LoRa.write(data);  // Payload：温度数据
  LoRa.endPacket();
}