我想通过arduino上连接sim900a模块实现连接onenet物联网平台的mqtt服务器(新版),想用sim900 a提供网络,不想用esp8266模块,应该如何写代码?下面这段代码在修改了对应值之后,创建mqtt客户端处有误,应如何修改?
#include <SoftwareSerial.h>
#include <PubSubClient.h>
// Sim900A配置
SoftwareSerial sim900aSerial(2, 3); // RX, TX
const char apn[] = "your_apn"; // 替换为您的APN
const char user[] = "your_user"; // 替换为您的APN用户名
const char pass[] = "your_pass"; // 替换为您的APN密码
// OneNET云平台配置
const char mqttServer[] = "oneNET_mqtt_broker_address"; // 替换为OneNET MQTT服务器地址
const uint16_t mqttPort = 1883; // MQTT默认端口
const char deviceId[] = "your_device_id"; // 替换为您的设备ID
const char apiKey[] = "your_api_key"; // 替换为您的API密钥
// 创建MQTT客户端实例
PubSubClient mqttClient(sim900aSerial);
void setup() {
// 初始化串口
Serial.begin(9600);
sim900aSerial.begin(19200);
// 设置Sim900A为GPRS模式
sim900aSerial.println("AT+CGATT=1");
delay(1000);
sim900aSerial.println("AT+CGDCONT=1,\"IP\",\"your_apn\""); // 替换为您的APN
delay(1000);
sim900aSerial.println("AT+CIPSHUTDOWN");
delay(1000);
sim900aSerial.println("AT+CIPMUX=0");
delay(1000);
sim900aSerial.println("AT+CSTT=\"your_apn\""); // 替换为您的APN
delay(1000);
sim900aSerial.println("AT+CIICR");
delay(3000);
}
void reconnect() {
// 尝试重新连接到MQTT服务器
while (!mqttClient.connected()) {
Serial.print("Attempting MQTT connection...");
// 创建一个随机的客户端ID
String clientId = "ArduinoClient-";
clientId += String(random(0xffff), HEX);
// 连接到MQTT服务器
if (mqttClient.connect(clientId.c_str(), deviceId, apiKey)) {
Serial.println("Connected to MQTT broker!");
// 订阅主题
mqttClient.subscribe("your_topic"); // 替换为您想订阅的主题
} else {
Serial.print("Failed with state ");
Serial.print(mqttClient.state());
Serial.println(" try again in 5 seconds");
// 等待5秒钟再次尝试
delay(5000);
}
}
}
void loop() {
// 保持MQTT客户端连接
if (!mqttClient.connected()) {
reconnect();
}
mqttClient.loop();
// 模拟数据,实际应用中应替换为传感器数据
float temperature = random(20, 30);
float humidity = random(40, 60);
// 构建JSON数据
String payload = "{\"temperature\":";
payload += String(temperature);
payload += ",\"humidity\":";
payload += String(humidity);
payload += "}";
// 发布数据到OneNET云平台
mqttClient.publish("your_topic", payload.c_str());
// 延迟一段时间再次发送数据
delay(10000);
}