Arduino から MQTT サーバーにメッセージを投げます。
使用機材
| 項目 | 設定値 |
|---|---|
| 使用している Arduino | arduino nano |
| 書き込みブートローダ | atmega328old |
| LAN シールド | ENC28J60 |
IPアドレス
| 端末 | IPアドレス |
|---|---|
| ルーター | 192.168.0.1 |
| Arduino | 192.168.0.117 |
| MQTT Server | 192.168.0.104 |
MQTT設定
| MQTT | 設定値 |
|---|---|
| server | 192.168.0.104 |
| ポート | 1883 |
| ルーム | test |
| クライアントID | myArduinoID |
| メッセージ | Hello World from arduino |
ソースコード
mqtt_pub.ino
# include <SPI.h>
# include <UIPEthernet.h>
# include <PubSubClient.h>
EthernetClient ethClient;
PubSubClient mqttClient(ethClient);
// Function prototypes
void subscribeReceive(char* topic, byte* payload, unsigned int length);
byte mac[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x78, 0xEE };
IPAddress ip(192, 168, 0, 117);
IPAddress myDns(192, 168, 0, 1);
// Make sure to leave out the http and slashes!
const char* server = "192.168.0.104";
void setup()
{
// Useful for debugging purposes
Serial.begin(9600);
// Start the ethernet connection
Ethernet.begin(mac, ip ,myDns);
// Ethernet takes some time to boot!
delay(3000);
// Set the MQTT server to the server stated above ^
mqttClient.setServer(server, 1883);
if (mqttClient.connect("myArduinoID")) {
Serial.println("Connection has been established, well done");
// Establish the subscribe event
mqttClient.setCallback(subscribeReceive);
} else {
Serial.println("Looks like the server connection failed...");
}
}
void loop(){
mqttClient.loop();
mqttClient.subscribe("test");
if(mqttClient.publish("test", "Hello World from arduino")){
Serial.println("Publish message success");
}else{
Serial.println("Could not send message :(");
}
// Dont overload the server!
delay(4000);
}
void subscribeReceive(char* topic, byte* payload, unsigned int length){
Serial.print("Topic: ");
Serial.println(topic);
Serial.print("Message: ");
for(int i = 0; i < length; i ++){
Serial.print(char(payload[i]));
}
Serial.println("");
}