• MCU board: ESP32 DevKitC 38-pin / esp32dev
• Framework: Arduino
• Build system: PlatformIO
• Library: madhephaestus/ESP32Servo

Ini
[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
lib_deps =
  madhephaestus/ESP32Servo@^3.0.6
build_flags =
  -DCORE_DEBUG_LEVEL=1

Cpp
#include <Arduino.h>
#include <WiFi.h>
#include <ESP32Servo.h>

constexpr uint8_t PIN_US_TRIG = 4;
constexpr uint8_t PIN_US_ECHO = 5;
constexpr uint8_t PIN_SERVO = 13;
constexpr uint8_t PIN_MIC = 34;
constexpr uint8_t PIN_SENSITIVITY = 35;
constexpr uint8_t LED_PINS[] = {12, 14, 27, 26, 25, 33};
constexpr size_t LED_COUNT = sizeof(LED_PINS) / sizeof(LED_PINS[0]);

const char *WIFI_SSID = "YOUR_SSID";
const char *WIFI_PASSWORD = "YOUR_PASSWORD";

Servo cityServo;
unsigned long lastSampleMs = 0;
unsigned long lastWiFiRetryMs = 0;

float readDistanceCm() {
  digitalWrite(PIN_US_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(PIN_US_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_US_TRIG, LOW);

  const unsigned long pulseUs = pulseIn(PIN_US_ECHO, HIGH, 30000UL);
  if (pulseUs == 0) return NAN;
  return static_cast<float>(pulseUs) * 0.0343f * 0.5f;
}

void setBuildingLevel(uint8_t activeChannels) {
  if (activeChannels > LED_COUNT) activeChannels = LED_COUNT;
  for (size_t i = 0; i < LED_COUNT; ++i) {
    digitalWrite(LED_PINS[i], i < activeChannels ? HIGH : LOW);
  }
}

void connectWiFi() {
  if (strcmp(WIFI_SSID, "YOUR_SSID") == 0) {
    Serial.println("Wi-Fi credentials not configured; continuing offline.");
    return;
  }
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("Connecting to Wi-Fi");
  for (int i = 0; i < 20 && WiFi.status() != WL_CONNECTED; ++i) {
    delay(500);
    Serial.print('.');
  }
  if (WiFi.status() == WL_CONNECTED) {
    Serial.printf("\nWi-Fi connected: %s\n", WiFi.localIP().toString().c_str());
  } else {
    Serial.println("\nWi-Fi unavailable; continuing offline.");
  }
}

void setup() {
  Serial.begin(115200);
  delay(200);

  pinMode(PIN_US_TRIG, OUTPUT);
  digitalWrite(PIN_US_TRIG, LOW);
  pinMode(PIN_US_ECHO, INPUT);

  for (uint8_t pin : LED_PINS) {
    pinMode(pin, OUTPUT);
    digitalWrite(pin, LOW); // GPIO12 must remain low during startup
  }

  analogReadResolution(12);
  analogSetPinAttenuation(PIN_MIC, ADC_11db);
  analogSetPinAttenuation(PIN_SENSITIVITY, ADC_11db);

  ESP32PWM::allocateTimer(0);
  cityServo.setPeriodHertz(50);
  cityServo.attach(PIN_SERVO, 500, 2400);
  cityServo.write(90);

  connectWiFi();
  Serial.println("Smart City Controller initialized.");
}

void loop() {
  const unsigned long now = millis();

  if (now - lastSampleMs >= 250) {
    lastSampleMs = now;

    const float distanceCm = readDistanceCm();
    const int micRaw = analogRead(PIN_MIC);
    const int sensitivityRaw = analogRead(PIN_SENSITIVITY);

    const uint8_t activeBuildings = map(sensitivityRaw, 0, 4095, 0, LED_COUNT + 1);
    setBuildingLevel(activeBuildings);

    int servoAngle = 90;
    if (!isnan(distanceCm)) {
      servoAngle = constrain(map(static_cast<long>(distanceCm), 5, 100, 0, 180), 0, 180);
      cityServo.write(servoAngle);
    }

    Serial.printf("distance_cm=%s mic=%d sensitivity=%d leds=%u servo=%d wifi=%s\n",
                  isnan(distanceCm) ? "timeout" : String(distanceCm, 1).c_str(),
                  micRaw, sensitivityRaw, activeBuildings, servoAngle,
                  WiFi.status() == WL_CONNECTED ? "connected" : "offline");
  }

  if (WiFi.status() != WL_CONNECTED &&
      strcmp(WIFI_SSID, "YOUR_SSID") != 0 &&
      now - lastWiFiRetryMs >= 30000) {
    lastWiFiRetryMs = now;
    WiFi.disconnect();
    connectWiFi();
  }

  delay(1);
}

Bash
pio run
pio run -t upload
pio device monitor