int led1 = 6;
int led2 = 7;
int led3 = 8;
int led4 = 9;
int led5 = 10;
int led6 = 11;
int led7 = 12;
int led8 = 13;
#define ECHO_PIN 2
#define TRIG_PIN 3
float buzzer = 5;
void setup() {
Serial.begin(115200);
pinMode(TRIG_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
pinMode(led1, OUTPUT);
}
float readDistanceCM() {
digitalWrite(TRIG_PIN, LOW);

delayMicroseconds(2);
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
int duration = pulseIn(ECHO_PIN, HIGH);
return duration * 0.034 / 2;
}
void loop() {
Serial.print("Measured distance: ");
Serial.println(readDistanceCM());
if (readDistanceCM() < 50) {
digitalWrite(buzzer, HIGH);
delay(500);
} else {
digitalWrite(buzzer, LOW);
delay(500);
}
if (readDistanceCM() <= 400 &&
readDistanceCM() > 350) {
digitalWrite(led1, HIGH);
digitalWrite(led2, HIGH);
digitalWrite(led3, HIGH);
digitalWrite(led4, HIGH);
digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 350 &&
readDistanceCM() > 300) {
digitalWrite(led1, LOW);
digitalWrite(led2, HIGH);
digitalWrite(led3, HIGH);
digitalWrite(led4, HIGH);
digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 300 &&
readDistanceCM() > 250) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, HIGH);
digitalWrite(led4, HIGH);
digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 250 &&
readDistanceCM() > 200) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, LOW);
digitalWrite(led4, HIGH);
digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 200 &&
readDistanceCM() > 150) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, LOW);

digitalWrite(led4, LOW);
digitalWrite(led5, HIGH);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 150 &&
readDistanceCM() > 100) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, LOW);
digitalWrite(led4, LOW);
digitalWrite(led5, LOW);
digitalWrite(led6, HIGH);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 100 &&
readDistanceCM() > 50) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, LOW);
digitalWrite(led4, LOW);
digitalWrite(led5, LOW);
digitalWrite(led6, LOW);
digitalWrite(led7, HIGH);
digitalWrite(led8, HIGH);
}
if (readDistanceCM() <= 50 &&
readDistanceCM() >=
0) {
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);
digitalWrite(led3, LOW);
digitalWrite(led4, LOW);
digitalWrite(led5, LOW);
digitalWrite(led6, LOW);
digitalWrite(led7, LOW);
digitalWrite(led8, HIGH);
}

delay
(100);
}