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分为以下部分： 1：接线并使用AT指令验证连接 2：使用软串口 3：搭建/配置/测试MQTT服务端 4：在Arduino实现MQTT的PUB客户端 5：总结
接线并使用AT指令验证连接
需要各种线+10k电阻*1 ESP8266的3V3/VCC 接到 3.3V ESP8266的EN 串联一个10k电阻 接到3.3V ESP8266的RX 接到 Arduino的RX0 ESP8266的TX 接到 Arduino的TX1 ESP8266的GND 接地
//验证程序
const int tx = 1;
const int rx = 0;
void setup() {
pinMode(rx,INPUT_PULLUP);
pinMode(tx,INPUT_PULLUP);
}
void loop() {
}
将Serial Monitor调整为Both NL&CR，115200 baud 输入AT，ESP8266蓝色灯光闪烁，返回OK 输入AT+GMR，返回版本等信息 如下：  至此，可以验证连接成功。
一些其他常用的AT命令：
AT+RST 重置wifi模块
AT+CWLAP 扫AP
AT+CWJAP=”SSID”,”PASSWORD” 连接到AP
AT+CWJAP=””,”” 与所有访问点断开连接
AT+CIFSR 显示获得的IP和MAC
AT+UART=9600,8,1,0,0 修改波特率等
AT+CWMODE= 设置工作模式，可有Station\AP\Station+AP三种
使用软串口
修改ESP8266的波特率为9600 假设将2，3分别作为RX，TX 则将ESP8266的RX与3（Arduino的TX）相连，反之亦如此 代码：
#include
SoftwareSerial mySerial(2, 3);
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
mySerial.println("AT+GMR");
}
void loop() {
if(wifiSerial.available()) {
Serial.write(wifiSerial.read());
}
if(Serial.available()){
wifiSerial.write(Serial.read());
}
}
之后打开Serial Monitor即可看到AT+GMR的执行结果了，也可以使用AT指令查看其他信息。
搭建/配置/测试MQTT服务端
服务器使用Ubuntu+mosquitto
apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
apt-get update
apt-get install mosquitto
cd /etc/mosquitto/conf.d
touch myconfig.conf
vim myconfig.conf
echo allow_anonymous false >> myconfig.conf
echo password_file /etc/mosquitto/pwfile.txt >> myconfig.conf
echo port 1883 >> myconfig.conf
mosquitto_passwd -c /etc/mosquitto/pwfile.txt [username]
service mosquitto start
在云平台调整服务器的安全组，放行出入1883端口的数据 使用python测试服务是否正常：
#sub.py
import paho.mqtt.client as mqtt
def on_connect(client, userdata, flags, rc):
print("Connect result:" + str(rc))
client.subscribe("test_topic")
def on_message(client, userdata, msg):
print(msg.topic+":" +str(msg.payload))
client = mqtt.Client("admin_sub")
client.username_pw_set("[username]","[password]")
client.on_connect = on_connect
client.on_message = on_message
print("Connectting…")
client.connect("[IP]", 1883, 60)
client.loop_forever()
#pub.py
import paho.mqtt.client as mqtt
def on_connect(client, userdata, flags, rc):
print("Connect result:" + str(rc))
def on_message(client, userdata, msg):
print(msg.topic + " " + str(msg.payload))
client = mqtt.Client("admin_pub")
client.on_connect = on_connect
client.on_message = on_message
client.connect('[IP]', 1883, 60)
client.publish('test_topic', payload='test_pub_content', qos=0)
可以连接/通讯，如图： 
在Arduino实现MQTT的PUB客户端
网上能找到的资料都需要烧写ESP8266，因为怕写坏自己唯一的板子，所以实现了软串口+TCP协议的MQTT客户端，站在别人肩膀上先实现Pub功能。没有做安全保护0.0。 最终实现效果及代码： 
#include
SoftwareSerial wifiSerial(2, 3);
bool on;
void setup()
{
Serial.begin(9600);
wifiSerial.begin(9600);
while (!Serial);
while (!wifiSerial);
wifiSerial.println("AT+RST");
on=false;
while(!on){
if(wifiSerial.find("OK")){
Serial.println("ESP8266 Resetting");
on = true;
}
}
on = false;
delay(5000); //Give enough time for ESP8266's reset
connect_wifi();
delay(1000);
pub_msg();
}
void loop() {
if(wifiSerial.available())
Serial.write(wifiSerial.read());
if(Serial.available()){
wifiSerial.write(Serial.read());
}
}
void connect_wifi(){
wifiSerial.println("AT+RST");
while(!on){
if(wifiSerial.find("ready")){
delay(1000);
on = true;
}
}
clear_serial();
on=false;
wifiSerial.println("AT+CWMODE=1");
wifiSerial.println("\"hausahan\",\"[password]\"");
delay(3000);
if(wifiSerial.find("OK")){
Serial.println("WIFI Connected!");
delay(1000);
clear_serial();
tcp_connect();
}
}
void tcp_connect(){
wifiSerial.println("AT+CIPSTART=\"TCP\",\"114.116.239.164\",1883");
delay(1000);
while(!on){
on = true;
if(wifiSerial.find("OK")){
Serial.println("TCP Connected!");
}
}
mqtt_connect();
}
void mqtt_connect(){
u8 mqttMessage[128]={0};
u8 packetLen;
u8 baseIndex = 0;
u8 clientIdLen = strlen("arduino_pub");
u8 UserNameLen = strlen("hausa");
u8 passwordLen = strlen("[password]");
packetLen = 16 + clientIdLen + UserNameLen + passwordLen;
mqttMessage[0] = 16;
mqttMessage[1] = packetLen - 2;
mqttMessage[3] = 4; // Protocol Name Length LSB
mqttMessage[4] = 77; // ASCII Code for M
mqttMessage[5] = 81; // ASCII Code for Q
mqttMessage[6] = 84; // ASCII Code for T
mqttMessage[7] = 84; // ASCII Code for T
mqttMessage[8] = 4; // MQTT Protocol version = 4
mqttMessage[9] = 130; // conn flags
mqttMessage[10] = 0; // Keep-alive Time Length MSB
mqttMessage[11] = 60; // Keep-alive Time Length LSB
mqttMessage[12] = (0xff00 & clientIdLen)>>8;// Client ID length MSB
mqttMessage[13] = 0xff & clientIdLen;
for(u8 i = 0; i
mqttMessage[baseIndex + i] = *((u8*)"hausa" + i);
}
baseIndex = 14 + clientIdLen + UserNameLen;
mqttMessage[baseIndex++] = (0xff00 & UserNameLen)>>8; //password length MSB
mqttMessage[baseIndex++] = 0xff & UserNameLen; //password length LSB
for(u8 i = 0; i
u8 mqttMessage[100]={0};
u16 i,index=0;
u16 topicLen = strlen("test_topic");
u16 messageLen = strlen("arduino_say_hi");
mqttMessage[index++] = 48;
mqttMessage[index++] = 2 + topicLen + messageLen;
mqttMessage[index++] = (0xff00 & topicLen)>>8;
mqttMessage[index++] = 0xff & topicLen;
for(i = 0; i
mqttMessage[index + i] = *((u8*)"arduino_say_hi" + i);
}
send_tcp_package(mqttMessage, 4 + topicLen + messageLen);
}
void send_tcp_package(u8 *data,u16 len){
clear_serial();
wifiSerial.print("AT+CIPSEND=");
wifiSerial.println(len);
delay(500);
if(wifiSerial.find(">")){
for(u16 i=0; i |