int pin = 9;
int data = 0;
char input;

void setup() {
  Serial.begin(9600);     // opens serial port, sets data rate to 9600 bps
}

void loop() {
  if(Serial.available()>0){
    input = Serial.read();
    Serial.println(input);
    
    if(input == 'g'){
      data = analogRead(pin);
      Serial.println(data);
    }
  }

}