Gas Leakage Detector

#include <Servo.h> 
Servo servo;

int gas = A0;
int green1 = 2;
int green2 = 4;
int green3 = 7;
int yellow1 = 8;
int yellow2 = 9;
int red1 = 10;
int red2 = 11;
int buzz = 5;
int motor = 3;
int pp = A1;

void setup() {
  pinMode(gas, INPUT);
  pinMode(green1, OUTPUT);
  pinMode(green2, OUTPUT);
  pinMode(green3, OUTPUT);
  pinMode(yellow1, OUTPUT);
  pinMode(yellow2, OUTPUT);
  pinMode(red1, OUTPUT);
  pinMode(red2, OUTPUT);
  pinMode(buzz, OUTPUT);
  pinMode(motor, OUTPUT);
  servo.attach(6);

  Serial.begin(9600);
}

void loop() {
  int pv = analogRead(pp);                          
  int range = map(pv, 0, 1023, 180, 600);            
  int gasValue = analogRead(gas);                    

  
  Serial.print("gas- ");
  Serial.print(gasValue);
  Serial.print("  threshold base- ");
  Serial.println(range);

  delay(200);

  digitalWrite(green1, LOW);
  digitalWrite(green2, LOW);
  digitalWrite(green3, LOW);
  digitalWrite(yellow1, LOW);
  digitalWrite(yellow2, LOW);
  digitalWrite(red1, LOW);
  digitalWrite(red2, LOW);
  digitalWrite(buzz, LOW);
  digitalWrite(motor, LOW);


  if (gasValue > range) {
    digitalWrite(green1, HIGH);
    servo.write(0);
  }
  if (gasValue > range + 70) {
    digitalWrite(green2, HIGH);
  }
  if (gasValue > range + 100) {
    digitalWrite(green3, HIGH);
  }
  if (gasValue > range + 130) {
    digitalWrite(yellow1, HIGH);
  }
  if (gasValue > range + 160) {
    digitalWrite(yellow2, HIGH);
  }
  if (gasValue > range + 220) {
    digitalWrite(red1, HIGH);
    digitalWrite(buzz, HIGH);
    digitalWrite(motor, HIGH);
    servo.write(90);
  }
  if (gasValue > range + 240) {
    digitalWrite(red2, HIGH);
  }

  delay(500);
}