Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>
#include <WebServer.h>
#include <HTTPClient.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";

String writeAPIKey = "4OXS308W9OG4KTHH";
String serverTS = "http://api.thingspeak.com/update?api_key=";

const int ledPin1 = 19;
const int ledPin2 = 18;
const int ledPin3 = 5;
const int ledPin4 = 17;

const int btn1 = 16;
const int btn2 = 4;
const int btn3 = 0;
const int btn4 = 2;

int lastBtn1 = HIGH, lastBtn2 = HIGH, lastBtn3 = HIGH, lastBtn4 = HIGH;

WebServer server(80);

String htmlPage = 
  "<!DOCTYPE html><html><head><title>ESP32 LED Control</title></head><body>"
  "<h2>Kontrol LED IoT (ESP32 + ThingSpeak)</h2>"
  "<form action='/led' method='POST'>"
  "<button name='nyala_1'>NYALAKAN LED 1</button>"
  "<button name='mati_1'>MATIKAN LED 1</button><br><br>"
  "<button name='nyala_2'>NYALAKAN LED 2</button>"
  "<button name='mati_2'>MATIKAN LED 2</button><br><br>"
  "<button name='nyala_3'>NYALAKAN LED 3</button>"
  "<button name='mati_3'>MATIKAN LED 3</button><br><br>"
  "<button name='nyala_4'>NYALAKAN LED 4</button>"
  "<button name='mati_4'>MATIKAN LED 4</button><br><br>"
  "</form></body></html>";

// ===== Variabel countdown =====
unsigned long lastUpdate = 0;
const unsigned long updateInterval = 15000; // 15 detik
bool countdownAktif = false;
unsigned long countdownStart = 0;

void updateThingSpeak(int field, int value) {
  unsigned long now = millis();
  if (now - lastUpdate >= updateInterval) {
    if (WiFi.status() == WL_CONNECTED) {
      HTTPClient http;
      String url = serverTS + writeAPIKey + "&field" + String(field) + "=" + String(value);
      http.begin(url);
      int httpCode = http.GET();
      if (httpCode > 0) {
        Serial.println("ThingSpeak updated: field" + String(field) + " = " + String(value));
      } else {
        Serial.println("Error updating ThingSpeak");
      }
      http.end();

      lastUpdate = now;

      // mulai countdown
      countdownAktif = true;
      countdownStart = millis();
    }
  } else {
    Serial.println("Update diblokir, tunggu cooldown selesai.");
  }
}

void setup() {
  Serial.begin(115200);

  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);

  digitalWrite(ledPin1, LOW);
  digitalWrite(ledPin2, LOW);
  digitalWrite(ledPin3, LOW);
  digitalWrite(ledPin4, LOW);

  pinMode(btn1, INPUT_PULLUP);
  pinMode(btn2, INPUT_PULLUP);
  pinMode(btn3, INPUT_PULLUP);
  pinMode(btn4, INPUT_PULLUP);

  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" Connected!");
  Serial.print("IP ESP32: ");
  Serial.println(WiFi.localIP());

  server.on("/", HTTP_GET, []() {
    server.send(200, "text/html", htmlPage);
  });

  server.on("/led", HTTP_POST, []() {
    if (server.hasArg("nyala_1")) {
      digitalWrite(ledPin1, HIGH);
      updateThingSpeak(1, 1);
    } else if (server.hasArg("mati_1")) {
      digitalWrite(ledPin1, LOW);
      updateThingSpeak(1, 0);
    } else if (server.hasArg("nyala_2")) {
      digitalWrite(ledPin2, HIGH);
      updateThingSpeak(2, 1);
    } else if (server.hasArg("mati_2")) {
      digitalWrite(ledPin2, LOW);
      updateThingSpeak(2, 0);
    } else if (server.hasArg("nyala_3")) {
      digitalWrite(ledPin3, HIGH);
      updateThingSpeak(3, 1);
    } else if (server.hasArg("mati_3")) {
      digitalWrite(ledPin3, LOW);
      updateThingSpeak(3, 0);
    } else if (server.hasArg("nyala_4")) {
      digitalWrite(ledPin4, HIGH);
      updateThingSpeak(4, 1);
    } else if (server.hasArg("mati_4")) {
      digitalWrite(ledPin4, LOW);
      updateThingSpeak(4, 0);
    }
    server.send(200, "text/html", htmlPage);
  });

  server.begin();
  Serial.println("Web server started!");
}

void loop() {
  server.handleClient();

  int btnState1 = digitalRead(btn1);
  if (btnState1 == LOW && lastBtn1 == HIGH) {
    digitalWrite(ledPin1, !digitalRead(ledPin1));
    updateThingSpeak(1, digitalRead(ledPin1));
  }
  lastBtn1 = btnState1;

  int btnState2 = digitalRead(btn2);
  if (btnState2 == LOW && lastBtn2 == HIGH) {
    digitalWrite(ledPin2, !digitalRead(ledPin2));
    updateThingSpeak(2, digitalRead(ledPin2));
  }
  lastBtn2 = btnState2;

  int btnState3 = digitalRead(btn3);
  if (btnState3 == LOW && lastBtn3 == HIGH) {
    digitalWrite(ledPin3, !digitalRead(ledPin3));
    updateThingSpeak(3, digitalRead(ledPin3));
  }
  lastBtn3 = btnState3;

  int btnState4 = digitalRead(btn4);
  if (btnState4 == LOW && lastBtn4 == HIGH) {
    digitalWrite(ledPin4, !digitalRead(ledPin4));
    updateThingSpeak(4, digitalRead(ledPin4));
  }
  lastBtn4 = btnState4;

  // ===== countdown display =====
  if (countdownAktif) {
    unsigned long elapsed = millis() - countdownStart;
    int detikSisa = updateInterval / 1000 - elapsed / 1000;

    if (detikSisa >= 0) {
      static int lastShown = -1;
      if (detikSisa != lastShown) {
        Serial.println("Cooldown: " + String(detikSisa) + " detik");
        lastShown = detikSisa;
      }
    } else {
      countdownAktif = false;
      Serial.println("Siap update lagi!");
    }
  }
}