gistfile1.txt

char val; // variable to receive data from the serial port


void setup() {
  Serial.begin(9600);       // start serial communication at 9600bps

}

void loop() {

  if( Serial.available() )       // if data is available to read
  {
    val = Serial.read();         // read it and store it in 'val'
  }
  if( val == 'd' )               // if 'H' was received
  {
   int mq3_value = analogRead(A0);
   Serial.print(" {'luminosity': ");
   Serial.print(mq3_value);
   Serial.println("}"); 
   delay(500);

}