const int bluePin = 25; // The pretty blue LED
const int redPin = 27; // Red LED const 
int greenPin = 26; // Green LED 
String incomingByte; // A variable to read incoming serial data into 

void setup() { 
    // Initialize serial communication: 
    Serial.begin(9600); 

    // Declare outputs: 
    pinMode(bluePin, OUTPUT); 
    pinMode(redPin, OUTPUT); 
    pinMode(greenPin, OUTPUT); 
} 
    
void loop() { 
    incomingByte = Serial.read();
    if (incomingByte == "b"){
      digitalWrite (bluePin, HIGH);
      digitalWrite (redPin, LOW);
      digitalWrite (greenPin, LOW);
            } 
     else if (incomingByte == "r"){
      digitalWrite (bluePin, LOW);
      digitalWrite (redPin, HIGH);
      digitalWrite (greenPin, LOW); 
     }
    else if (incomingByte == "g"){
      digitalWrite (bluePin, LOW);
      digitalWrite (redPin, LOW);
      digitalWrite (greenPin, HIGH);
    }

}