int ndrdy = A4;
int clck = A5; 
int pwm = 3;

void setup() {
    Serial.begin(115200);
    pinMode(pwm, OUTPUT);
    
    while (!Serial) {}
    digitalWrite(ndrdy, LOW);
    pinMode(ndrdy, INPUT);

    digitalWrite(clck, LOW);
    pinMode(clck, OUTPUT);

    while (digitalRead(ndrdy)) {}
    while (!digitalRead(ndrdy)) {}
}

long readADC() 
{
    if (digitalRead(ndrdy))
        return -1;

    long result = 0;

    for (int i = 0; i < 24; i++) 
    {
        digitalWrite(clck, HIGH);
        delayMicroseconds(1);
        int new_bit = digitalRead(ndrdy);
        digitalWrite(clck, LOW);
        delayMicroseconds(1);
        result <<= 1;
        result |= new_bit;
    }

    for (int i = 0; i < 3; i++) 
    {
        digitalWrite(clck, HIGH);
        delayMicroseconds(1);      
        digitalWrite(clck, LOW);
        delayMicroseconds(1);
    }

    return result; 
}


void loop() {  
  long adcValue = readADC();
  Serial.print("ADC reading: ");
  Serial.print(adcValue);
  if (adcValue >= 3400000)
  {
    delay(500);
    analogWrite(pwm,0);
    Serial.println(" End of Run ");
    delay(500);
  }
  else
  {
    if (is_run == true)
    {
      analogWrite(pwm,255);
      delay(500);
    }
  }
}