Result in the in-lab exercises

The photo is attached.

In this part, i use three variables redCount, greenCount, and blueCount to count how many repetitions of each r, g, b are. Then, i set the brightness based on the calcucated percentage.

Code

/*
 * Serial RGB LED
 * ---------------
 * Serial commands control the brightness of R,G,B LEDs
 
 * Command structure is "<colorCode>*", where "colorCode" is
 * one of "r","g", or "b".
 * For example, pressing ‘r’ 5 times will set the brightness to 50% (or brightness = 127)
 * and pressing ‘r’ 10 times will set it to 100% (or brightness = 255).
 *
 *
 *
 */
 
//include support for manipulating strings.
//for a useful string comparison function, see the bottom of this file... stringsEqual()
#include <stdio.h>
#include <string.h>

char serInString[100];  // array that will hold the different bytes of the string. 100=100characters;
                        // -> you must state how long the array will be else it won't work properly
char colorCode;
int colorVal;

int redPin   = 9;   // Red LED,   connected to digital pin 9
int greenPin = 10;  // Green LED, connected to digital pin 10
int bluePin  = 11;  // Blue LED,  connected to digital pin 11

int redValue = 127;
int greenValue = 127;
int blueValue = 127;

void setup() {
  pinMode(redPin,   OUTPUT);   // sets the pins as output
  pinMode(greenPin, OUTPUT);  
  pinMode(bluePin,  OUTPUT);
  Serial.begin(9600);
  analogWrite(redPin,   redValue);   // set them all to mid brightness
  analogWrite(greenPin, greenValue);   // set them all to mid brightness
  analogWrite(bluePin,  blueValue);   // set them all to mid brightness
  Serial.println("enter color command (e.g. 'r43 or rrrrrrrrbbbb') :"); 
}

void loop () {
  //read the serial port and create a string out of what you read
  readSerialString(serInString, 100);

   
  //UNCOMMENT ONE OF THE FOLLOWING COMMANDS, OR NOTHING WILL HAPPEN WHEN YOU
  //RUN THE PROGRAM...
  
  myProcessRepeatKeyCommands(serInString, 100);

  //Erase anything left in the serial string, preparing it for the
  //next loop
  resetSerialString(serInString, 100); 

  delay(100);  // wait a bit, for serial data
}

void resetSerialString (char *strArray, int length) {
  for (int i = 0; i < length; i++) {
    strArray[i] = '\0';
  }
}

//read a string from the serial and store it in an array
//you must supply the array variable
void readSerialString (char *strArray, int maxLength) {
  int i = 0;

  if(!Serial.available()) {
    return;
  }
  while (Serial.available() && i < maxLength) {
    strArray[i] = Serial.read();
    i++;
  }
}

void myProcessRepeatKeyCommands(char *strArray, int maxLength) {
  int i = 0;
 
 
  int redCount = 0, greenCount = 0, blueCount = 0;
  //loop through the string (strArray)
  //i = the current position in the string
  //Stop when either (a) i reaches the end of the string or
  //                 (b) there is an empty character '\0' in the string
  while (i < maxLength && strArray[i] != '\0') {
    //Read in the character at position i in the string
    colorCode = serInString[i];
   
    //If the character is r (red)...
    if (colorCode == 'r') {
      redCount ++;
     
    //If the character is g (green)...
    } else if (colorCode == 'g') {
      greenCount ++;
   
    //If the character is b (blue)...
    } else if (colorCode == 'b') {
      blueCount ++;
    }
   
    //Move on to the next character in the string
    //From here, the code continues executing from the "while" line above...
    i++;
  }
 
  if (i > 0) {
 
      redValue = 255 * redCount / 10;
      analogWrite(redPin, redValue);
      Serial.print("setting color r to ");
      Serial.println(redValue);
      greenValue = 255 * greenCount / 10;
      analogWrite(greenPin, greenValue);
      Serial.print("setting color g to ");
      Serial.println(greenValue); 
      blueValue = 255 * blueCount / 10;
      analogWrite(bluePin, blueValue);
      Serial.print("setting color b to ");
      Serial.println(blueValue);

  }
 
}