   {
     ppm = readPPM();
   
-    Serial.print("6713 ppm: ");
-    Serial.println(ppm);
+    Serial.print("6713: ");
+    Serial.print(ppm);
+    Serial.println(" ppm");
      readVOC();
 	// 6713 sample CO2 every 5 seconds
     delay(5000);

void setup() {
  Serial.begin(115200);
  Wire.begin();
  delay(5000);
  attachInterrupt(1, rising, RISING);
}


  }
  pwm_co2 = 40*pwm_value1-1800;
  pwm_voc = 25*pwm_value2-125;
  
  Serial.print("SGX in PWM (%): CO2 ");  
  Serial.print(pwm_value1);
  Serial.print(" VOC ");
  Serial.println(pwm_value2);
  Serial.print("CO2: ");
  Serial.print(pwm_co2);
  Serial.print(" ppm ");
  Serial.print(" VOC: ");
  Serial.print(pwm_voc);
  Serial.println(" ppa");
}

// the loop function runs over and over again forever
