esp32_relay

#include <WiFi.h>
#include <PubSubClient.h>
int a[8] = { 13, 27, 26, 25, 23, 19, 18, 4 };
const char* ssid = "NAMA WIFI";
const char* password = "PASSWORD WIFI";
const char* mqtt_server = "xxx.xxx.xxx.xxx"; //ALAMAT IP RASPBERRY
WiFiClient espClient;
PubSubClient client(espClient);
void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  randomSeed(micros());
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}
void callback(char* topic, byte* payload, unsigned int length) {
  char data1 = (char)payload[0];
  char data2 = (char)payload[1];
  switch (data1) {
    case 'a':
      if (data2 == '1') digitalWrite(a[0], LOW);
      if (data2 == '0') digitalWrite(a[0], HIGH);
      break;
    case 'b':
      if (data2 == '1') digitalWrite(a[1], LOW);
      if (data2 == '0') digitalWrite(a[1], HIGH);
      break;
    case 'c':
      if (data2 == '1') digitalWrite(a[2], LOW);
      if (data2 == '0') digitalWrite(a[2], HIGH);
      break;
    case 'd':
      if (data2 == '1') digitalWrite(a[3], LOW);
      if (data2 == '0') digitalWrite(a[3], HIGH);
      break;
    case 'e':
      if (data2 == '1') digitalWrite(a[4], LOW);
      if (data2 == '0') digitalWrite(a[4], HIGH);
      break;
    case 'f':
      if (data2 == '1') digitalWrite(a[5], LOW);
      if (data2 == '0') digitalWrite(a[5], HIGH);
      break;
    case 'g':
      if (data2 == '1') digitalWrite(a[6], LOW);
      if (data2 == '0') digitalWrite(a[6], HIGH);
      break;
    case 'h':
      if (data2 == '1') digitalWrite(a[7], LOW);
      if (data2 == '0') digitalWrite(a[7], HIGH);
      break;
  }
}
void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      client.subscribe("/esp32/relay"); // TOPIK UNTUK SUBSCRIBER
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}
void setup() {
  for (int i = 0; i < 8; i++) {
    pinMode(a[i], OUTPUT);
    digitalWrite(a[i], HIGH);
  }
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}
void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}