School Cafeteria's Trash Can Upgrade Project Lv.2

int trigPin = 9;
3int echoPin = 8;
4int led = 7;
5int led2 = 6;
6int led3 = 5;
7int led4 = 4;
8long distance;
9long duration;
10void setup() {
11Serial.begin(9600);
12pinMode(trigPin, OUTPUT);
13pinMode(echoPin, INPUT);
14pinMode (led,OUTPUT);
15pinMode (led2,OUTPUT);
16pinMode (led3,OUTPUT);
17pinMode (led4,OUTPUT);
18}
19void loop() {
20  ultra();// put your main code here, to run repeatedly:
21  Serial.println(distance);
22  LV0();
23  delay(50);
24  LV1();
25  delay(50);
26  LV2();
27  delay(50);
28  LV3();
29  delay(50);
30  LV4();
31  delay(50);
32    if (distance>=5){
33    digitalWrite(led4,LOW);
34  }
35}
36void ultra(){ // Clears the trigPin
37digitalWrite(trigPin, LOW);
38delayMicroseconds(2);// Sets the trigPin on HIGH state for 10 micro seconds
39digitalWrite(trigPin, HIGH);
40delayMicroseconds(10);
41digitalWrite(trigPin, LOW);// Reads the echoPin, returns the sound wave travel time in microseconds
42duration = pulseIn(echoPin, HIGH);// Calculating the distance
43distance= duration*0.034/2;
44}
45void LV0(){
46  if(distance>30){
47    digitalWrite(led,LOW);
48    delay(100);
49    digitalWrite(led2,LOW);
50    delay(100);
51    digitalWrite(led3,LOW);
52    delay(100);
53    digitalWrite(led4,LOW);
54    delay(100);
55  }
56}
57void LV1(){
58  if(distance<=30 and distance>21){
59    digitalWrite(led,HIGH);
60    delay(100);
61    digitalWrite(led,LOW);
62    delay(100);
63  }
64}/*1단계 led만 점멸등 2,3,4단계는 항상 off*/
65void LV2(){
66  if(distance<=21 and distance>12){
67    digitalWrite(led,HIGH);
68    digitalWrite(led2,HIGH);
69    delay(100);
70    digitalWrite(led2,LOW);
71    delay(100);
72  }
73}/*2단계 led만 점멸등 1단계는 항상 on 3,4단계는 항상 off*/
74void LV3(){
75  if (distance<=12 and distance>5){
76    digitalWrite(led,HIGH);
77    digitalWrite(led2,HIGH);
78    digitalWrite(led3,HIGH);
79    delay(100);
80    digitalWrite(led3,LOW);
81    delay(100);
82  }
83}/*3단계 led만 점멸등 1,2단계는 항상 on 4단계는 항상 off*/
84void LV4(){
85  if (distance<=5){
86    digitalWrite(led,HIGH);
87    digitalWrite(led2,HIGH);
88    digitalWrite(led3,HIGH);
89    digitalWrite(led4,HIGH);
90  }
91}/*4단계 led만 점멸등 1,2,3단계는 항상 on*/