Basic code to control 8 bit shift register

website_monitor.ino

/*
Adafruit Arduino - Lesson 4. 8 LEDs and a Shift Register - Brightness
*/
 
int latchPin = 5;
int clockPin = 6;
int dataPin = 4;
int outputEnablePin = 3;
 
byte leds = 0;

String inputString = ""; // a string to hold incoming data
boolean stringComplete = false; // for serial message complete
String location = "";
boolean california = false;
boolean uk = false;
boolean moscow = false;
boolean sydney = false;

void setup() 
{
  Serial.begin(9600);
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);  
  pinMode(clockPin, OUTPUT);
  pinMode(outputEnablePin, OUTPUT); 
  setBrightness(255);
  
  // set all to red
  Serial.println("All Red");
  bitSet(leds, 0);
  bitSet(leds, 2);
  bitSet(leds, 4);
  bitSet(leds, 6);
  updateShiftRegister();
//  delay(2000);
//  bitSet(leds, 1);
//  bitSet(leds, 3);
//  bitSet(leds, 5);
//  bitSet(leds, 7);
//  updateShiftRegister();
}
 
void loop() 
{
  if (stringComplete) {
    inputString.replace("\n","");
    location = inputString;
    Serial.println(location);
    changeLEDState();
    // clear the string:
    inputString = "";
    stringComplete = false;
  }
  delay(500);
}

void changeLEDState()
{
  if (location == "california") {
    // green for ok or true
    if (california == true) {
      Serial.println("updating California to down");
      bitClear(leds, 1);
      updateShiftRegister();
      bitSet(leds, 0);
      updateShiftRegister();
      california = !california; 
    } else {
      Serial.println("updating California to up");
      bitClear(leds, 0);
      updateShiftRegister();
      bitSet(leds, 1);
      updateShiftRegister();
      california = !california;
    }
  }
  else if (location == "uk") {
    // green for ok or true
    if (uk == true) {
      Serial.println("updating uk to down");
      bitClear(leds, 3);
      updateShiftRegister();
      bitSet(leds, 2);
      updateShiftRegister();
      uk = !uk; 
    } else {
      Serial.println("updating uk to up");
      bitClear(leds, 2);
      updateShiftRegister();
      bitSet(leds, 3);
      updateShiftRegister();
      uk = !uk;
    }
  } else if (location == "moscow") {
    // green for ok or true
    if (moscow == true) {
      Serial.println("updating moscow to down");
      bitClear(leds, 5);
      updateShiftRegister();
      bitSet(leds, 4);
      updateShiftRegister();
      moscow = !moscow; 
    } else {
      Serial.println("updating moscow to up");
      bitClear(leds, 4);
      updateShiftRegister();
      bitSet(leds, 5);
      updateShiftRegister();
      moscow = !moscow;
    }
  } else if (location == "sydney") {
    // green for ok or true
    if (sydney == true) {
      Serial.println("updating sydney to down");
      bitClear(leds, 7);
      updateShiftRegister();
      bitSet(leds, 6);
      updateShiftRegister();
      sydney = !sydney; 
    } else {
      Serial.println("updating sydney to up");
      bitClear(leds, 6);
      updateShiftRegister;
      bitSet(leds, 7);
      updateShiftRegister();
      sydney = !sydney;
    }
  }
}

void serialEvent() {
  while (Serial.available()) {
    // get the new byte:  
    char inChar = (char)Serial.read();
    // add it to the inputString:
    inputString += inChar;
    // if the incoming character is a newline, set a flag
    // so the main loop can do something about it:
    if (inChar == '\n') {
      stringComplete = true;
    }
  }
}

void updateShiftRegister()
{
   digitalWrite(latchPin, LOW);
   shiftOut(dataPin, clockPin, LSBFIRST, leds);
   digitalWrite(latchPin, HIGH);
}
 
void setBrightness(byte brightness) // 0 to 255
{
  analogWrite(outputEnablePin, 255-brightness);
}