ESP32 Control 4 RELAY by Node-Red MQTT
WOKWI程式
#include <WiFi.h>
#include <PubSubClient.h> //請先安裝PubSubClient程式庫
// ------ 以下修改成你自己的WiFi帳號密碼 ------
char* ssid = "Wokwi-GUEST"; //請修改為您連線的網路名稱
char* password = ""; //請修改為您連線的網路密碼
// ------ 以下修改成你MQTT設定 ------
char* MQTTServer = "mqttgo.io";//免註冊MQTT伺服器
int MQTTPort = 1883;//MQTT Port 除非加密，否則不用更改port
char* MQTTUser = "";//不須帳密
char* MQTTPassword = "";//不須帳密
// Topics 訂閱主題1:訂閱訊息(記得改Topic)
const char* relay_topic = "alex9ufo/esp32/relay";
char* MQTTPubTopic1 = "alex9ufo/esp32/relay_back";
// Relay pins
const int relay1 = 23; //繼電器1 ON =亮
const int relay2 = 22; //繼電器2 ON =亮
const int relay3 = 21; //繼電器3 ON =亮
const int relay4 = 19; //繼電器4 ON =亮
//建立MQTT與聯網物件
WiFiClient WifiClient;
PubSubClient MQTTClient(WifiClient);
//建立變數資料
int num=1234567890;
//==========================================================
// Callback function
void callback(char* topic, byte* payload, unsigned int length) {
payload[length] = '\0';
String message = String((char*)payload);
Serial.print("Message arrived in topic: ");
Serial.println(topic);
Serial.print("Message: ");
Serial.println( message);
if (String(topic) == relay_topic) {
// Control relay
if (message == "OFF1")
digitalWrite(relay1, LOW); // LOW to activate
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "ON1")
digitalWrite(relay1, HIGH);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "OFF2")
digitalWrite(relay2, LOW);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "ON2")
digitalWrite(relay2, HIGH);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "OFF3")
digitalWrite(relay3, LOW);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "ON3")
digitalWrite(relay3, HIGH);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "OFF4")
digitalWrite(relay4, LOW);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "ON4")
digitalWrite(relay4, HIGH);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
if (message == "ALLON")
{
digitalWrite(relay1, HIGH);
digitalWrite(relay2, HIGH);
digitalWrite(relay3, HIGH);
digitalWrite(relay4, HIGH);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
}
if (message == "ALLOFF")
{
digitalWrite(relay1, LOW);
digitalWrite(relay2, LOW);
digitalWrite(relay3, LOW);
digitalWrite(relay4, LOW);
MQTTClient.publish(MQTTPubTopic1,message.c_str());
Serial.print( "Published Topic:alex9ufo/esp32/relay_back-->");
Serial.println(message);
}
}
}
//==========================================================
//開始WiFi連線
void WifiConnecte() {
//開始WiFi連線
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("WiFi連線成功");
Serial.print("IP Address:");
Serial.println(WiFi.localIP());
}
//==========================================================
//開始MQTT連線
void MQTTConnecte() {
MQTTClient.setServer(MQTTServer, MQTTPort);
while (!MQTTClient.connected()) {
//以亂數為ClietID
String MQTTClientid = "esp32-" + String(random(1000000, 9999999));//建立一個id，MQTT要求id要不一樣，所以使用亂數
if (MQTTClient.connect(MQTTClientid.c_str(), MQTTUser, MQTTPassword)) {
//連結成功，顯示「已連線」。
Serial.println("MQTT已連線");
} else {
//若連線不成功，則顯示錯誤訊息，並重新連線
Serial.print("MQTT連線失敗,狀態碼=");
Serial.println(MQTTClient.state());
Serial.println("五秒後重新連線");
delay(5000);
}
}
}
//==========================================================
//==========================================================
void setup() {
Serial.begin(115200);
Serial.begin(115200);
pinMode(relay1, OUTPUT); //輸出模式
pinMode(relay2, OUTPUT);
pinMode(relay3, OUTPUT);
pinMode(relay4, OUTPUT);
digitalWrite(relay1, LOW); //LED熄滅
digitalWrite(relay2, LOW);
digitalWrite(relay3, LOW);
digitalWrite(relay4, LOW);
//開始WiFi連線
WifiConnecte();
//開始MQTT連線
MQTTConnecte();
MQTTClient.setCallback(callback);
MQTTClient.subscribe(relay_topic);
}
//==========================================================
void loop() {
//如果WiFi連線中斷，則重啟WiFi連線
if (WiFi.status() != WL_CONNECTED) { WifiConnecte(); }
//如果MQTT連線中斷，則重啟MQTT連線
if (!MQTTClient.connected()) { MQTTConnecte(); }
MQTTClient.loop();//更新訂閱狀態
delay(50);
}
//==========================================================
