미세먼지 센서에서 값을 받아서 모터를 돌리는 구성입니다. 
모터만 따로 구동하는 코드로는 모터가 작동하고
미세먼지센서로 lcd모니터에 값을 띄우는 코드도 작동합니다.
두 코드를 결합하면 모터가 구동이 안돼서 그러는데 피드백 부탁드립니다 ㅜㅜ
 
#include <LiquidCrystal_I2C.h>
#include <Wire.h>

#define DIR 5
#define STEP 4

#define STEP_DELAY 500
#define STEP_COUNT 1000

LiquidCrystal_I2C lcd (0x27, 16, 2);

int Dust = 0;
char str1[10];

int Vo = A0;
int V_LED = 2;

float Vo_value = 0;
float Voltage = 0;

void setup()
{
  Wire.begin();
  Serial.begin(9600);
  while(!Serial);
  Serial.println("\nI2C Scanner");

  pinMode(V_LED, OUTPUT);
  pinMode(Vo, INPUT);

  pinMode(DIR, OUTPUT);
  pinMode(STEP, OUTPUT);
  digitalWrite(DIR, HIGH);

  lcd.begin();
  lcd.noBacklight();
  lcd.clear();
  delay(500);

  lcd.backlight();
  delay(500);

  lcd.setCursor(6, 0);
  lcd.print("SENSOR");
  delay(1000);
  lcd.clear();
}

void loop()
{
  digitalWrite(V_LED, LOW);
  delayMicroseconds(280);
  Vo_value = analogRead(Vo);
  delayMicroseconds(40);
  digitalWrite(V_LED, HIGH);
  delayMicroseconds(9680);

  Voltage = Vo_value * 5.0 / 1023.0;

  Serial.print(" Volatage: ");
  Serial.println(Voltage);

  if (Voltage < 0.1) {
    Dust = 0;
  }
  else if (Voltage < 0.8) {
    Dust = 10 * (5 * (Voltage - 0.1));
  }
  else if (Voltage < 1) {
    Dust = 10 + 15 * ((Voltage - 0.8) * 10);
  }
  else if (Voltage > 1) {
    Dust = 40 + 16 * ((Voltage - 1) * 10);
  }

  Serial.print("Dust : ");
  Serial.println(Dust);
  Serial.println(" ");

  delay(10);

  lcd.setCursor(1, 0);
  lcd.print("Dust : ");
  sprintf(str1, "%03d", Dust);
  lcd.print(str1);

  lcd.write(0);
  lcd.print("g/m");
  lcd.write(1);

  digitalWrite(DIR, HIGH);
  for(int i = 0; i < STEP_COUNT; i++) {
    digitalWrite(STEP, HIGH);
    delayMicroseconds(STEP_DELAY);
    digitalWrite(STEP, LOW);
    delayMicroseconds(STEP_DELAY);
  }

  digitalWrite(DIR, LOW);
  for(int i = 0; i < STEP_COUNT; i++) {
    digitalWrite(STEP, HIGH);
    delayMicroseconds(STEP_DELAY);
    digitalWrite(STEP, LOW);
    delayMicroseconds(STEP_DELAY);
  }
  
  delay(10);
}