ArduinoUNO+ESP8266实现MQTT简单发布（不烧录ESP8266）

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.h>
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.h>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 MSBmqttMessage[13] = 0xff & clientIdLen; for(u8 i = 0; i < clientIdLen; i++){mqttMessage[14 + i] = *((u8*)"arduino_pub" + i);    }baseIndex = 14 + clientIdLen;mqttMessage[baseIndex++] = (0xff00 & UserNameLen)>>8; //username length MSB    mqttMessage[baseIndex++] = 0xff & UserNameLen;        //username length LSB for(u8 i = 0; i < UserNameLen ; 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 < UserNameLen ; i++){mqttMessage[baseIndex + i] = *((u8*)"[password]" + i);    }send_tcp_package(mqttMessage, packetLen);
}void pub_msg(){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 < topicLen; i++){mqttMessage[index + i] = *((u8 *)"test_topic" + i);}index += topicLen;for(i = 0; i < messageLen; 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<len; i++)wifiSerial.write(data[i]);wifiSerial.println();delay(500);}
}void clear_serial(){while(wifiSerial.read()>= 0);while(Serial.read()>= 0);
}

总结

还是有很多让人疑惑的问题的，比如：
ESP8266很多指令执行后必须等几秒才能进行下一步操作。
也有收获：
每次编程后使用AT+RST进行重置并在烧写完成后复位Arduino能解决很多奇怪的问题。
更理解通信协议、协议栈、wireshark的使用、、、等知识了
下一步：
考虑多买几块8266，学习直接使用8266的方法，因为看起来好像很方便，并实现一个远程控制LED的Deeeeeemo。再然后怎么不做一套智能家居？