   
   Serial.println("---------------------");
   
-  // MAX 4466 amp
-  //Serial.println(analogRead(A0));  // read sound levels
-  //Serial.println();
+  // ADMP401 mic for sound level
+  Serial.print("Sound Level: ");
+  Serial.print(analogRead(A0));  // read sound levels
+  Serial.println();
 
 
   // TSL2561 light sensor

  //Serial.println(Rs);
  //Serial.println(R0);
  //Serial.println(ratio);
  Serial.println(concentration);
  return concentration;
}


// define MICS-4514 global variables
#define PRE_PIN          8
#define VNOX_PIN         A1
#define VRED_PIN         A2
#define PRE_HEAT_SECONDS 10
int vnox_value = 0;
int vred_value = 0;
