Week 3: Multiple LEDs and Arrays

Array of LEDs on an Arduino
UnoArduSim
UnoArduSim

Following on from week 1 and week 2, we will be continuing our way through Oomlout’s Arduino Guide, at this point however we hit a snag with using iCircuit. Annoyingly iCircuit is unable to deal with arrays. An array is a cunning way of holding multiple variables inside a single variable without musshing them together.

However UnoArduSim does manage arrays, so will work with that.

The code we are running above is

/*     ---------------------------------------------------------
 *     |  Arduino Experimentation Kit Example Code             |
 *     |  CIRC-02 .: 8 LED Fun :. (Multiple LEDs)   |
 *     ---------------------------------------------------------
 *  
 *  A few Simple LED animations
 *
 * For more information on this circuit http://tinyurl.com/d2hrud
 *
 */
 
//LED Pin Variables
int ledPins[] = {2,3,4,5,6,7,8,9}; //An array to hold the pin each LED is connected to
                                   //i.e. LED #0 is connected to pin 2, LED #1, 3 and so on
                                   //to address an array use ledPins[0] this would equal 2
                                   //and ledPins[7] would equal 9
 
/*
 * setup() - this function runs once when you turn your Arduino on
 * We the three control pins to outputs
 */
void setup()
{
  
  //Set each pin connected to an LED to output mode (pulling high (on) or low (off)
  for(int i = 0; i < 8; i++){         //this is a loop and will repeat eight times
      pinMode(ledPins[i],OUTPUT);     //we use this to set each LED pin to output
  }                                   //the code this replaces is below
 
  /* (commented code will not run)
   * these are the lines replaced by the for loop above they do exactly the
   * same thing the one above just uses less typing
  pinMode(ledPins[0],OUTPUT);
  pinMode(ledPins[1],OUTPUT);
  pinMode(ledPins[2],OUTPUT);
  pinMode(ledPins[3],OUTPUT);
  pinMode(ledPins[4],OUTPUT);
  pinMode(ledPins[5],OUTPUT);
  pinMode(ledPins[6],OUTPUT);
  pinMode(ledPins[7],OUTPUT);
  (end of commented code)*/
}
 
 
/*
 * loop() - this function will start after setup finishes and then repeat
 * we call a function called oneAfterAnother(). if you would like a different behaviour
 * uncomment (delete the two slashes) one of the other lines
 */
void loop()                     // run over and over again
{
  oneAfterAnotherNoLoop();   //this will turn on each LED one by one then turn each off
  //oneAfterAnotherLoop();   //does the same as oneAfterAnotherNoLoop but with much less typing
  //oneOnAtATime();          //this will turn one LED on then turn the next one
                             //on turning the former off (one LED will look like it is scrolling along the line
  //inAndOut();              //lights the two middle LEDs then moves them out then back in again
}
 
/*
 * oneAfterAnotherNoLoop() - Will light one LED then delay for delayTime then light
 * the next LED until all LEDs are on it will then turn them off one after another
 *
 * this does it without using a loop which makes for a lot of typing. 
 * oneOnAtATimeLoop() does exactly the same thing with less typing
 */
void oneAfterAnotherNoLoop(){
  int delayTime = 100; //the time (in milliseconds) to pause between LEDs
                       //make smaller for quicker switching and larger for slower
  digitalWrite(ledPins[0], HIGH);  //Turns on LED #0 (connected to pin 2 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[1], HIGH);  //Turns on LED #1 (connected to pin 3 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[2], HIGH);  //Turns on LED #2 (connected to pin 4 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[3], HIGH);  //Turns on LED #3 (connected to pin 5 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[4], HIGH);  //Turns on LED #4 (connected to pin 6 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[5], HIGH);  //Turns on LED #5 (connected to pin 7 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[6], HIGH);  //Turns on LED #6 (connected to pin 8 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[7], HIGH);  //Turns on LED #7 (connected to pin 9 )
  delay(delayTime);                //waits delayTime milliseconds  
 
//Turns Each LED Off
  digitalWrite(ledPins[7], LOW);  //Turns on LED #0 (connected to pin 2 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[6], LOW);  //Turns on LED #1 (connected to pin 3 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[5], LOW);  //Turns on LED #2 (connected to pin 4 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[4], LOW);  //Turns on LED #3 (connected to pin 5 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[3], LOW);  //Turns on LED #4 (connected to pin 6 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[2], LOW);  //Turns on LED #5 (connected to pin 7 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[1], LOW);  //Turns on LED #6 (connected to pin 8 )
  delay(delayTime);                //waits delayTime milliseconds
  digitalWrite(ledPins[0], LOW);  //Turns on LED #7 (connected to pin 9 )
  delay(delayTime);                //waits delayTime milliseconds  
}
 
/*
 * oneAfterAnotherLoop() - Will light one LED then delay for delayTime then light
 * the next LED until all LEDs are on it will then turn them off one after another
 *
 * this does it using a loop which makes for a lot less typing. 
 * than oneOnAtATimeNoLoop() does exactly the same thing with less typing
 */
void oneAfterAnotherLoop(){
  int delayTime = 100; //the time (in milliseconds) to pause between LEDs
                       //make smaller for quicker switching and larger for slower
 
//Turn Each LED on one after another
  for(int i = 0; i <= 7; i++){ digitalWrite(ledPins[i], HIGH); //Turns on LED #i each time this runs i delay(delayTime); //gets one added to it so this will repeat } //8 times the first time i will = 0 the final //time i will equal 7; //Turn Each LED off one after another for(int i = 7; i >= 0; i--){  //same as above but rather than starting at 0 and counting up
                                //we start at seven and count down
    digitalWrite(ledPins[i], LOW);  //Turns off LED #i each time this runs i
    delay(delayTime);                //gets one subtracted from it so this will repeat 
  }                                  //8 times the first time i will = 7 the final
                                     //time it will equal 0
                                     
                                     
}
 
/*
 * oneOnAtATime() - Will light one LED then the next turning off all the others
 */
void oneOnAtATime(){
  int delayTime = 100; //the time (in milliseconds) to pause between LEDs
                       //make smaller for quicker switching and larger for slower
  
  for(int i = 0; i <= 7; i++){
    int offLED = i - 1;  //Calculate which LED was turned on last time through
    if(i == 0) {         //for i = 1 to 7 this is i minus 1 (i.e. if i = 2 we will
      offLED = 7;        //turn on LED 2 and off LED 1)
    }                    //however if i = 0 we don't want to turn of led -1 (doesn't exist)
                         //instead we turn off LED 7, (looping around)
    digitalWrite(ledPins[i], HIGH);     //turn on LED #i
    digitalWrite(ledPins[offLED], LOW); //turn off the LED we turned on last time
    delay(delayTime);
  }
}
 
/*
 * inAndOut() - This will turn on the two middle LEDs then the next two out
 * making an in and out look
 */
void inAndOut(){
  int delayTime = 100; //the time (in milliseconds) to pause between LEDs
                       //make smaller for quicker switching and larger for slower
  
  //runs the LEDs out from the middle
  for(int i = 0; i <= 3; i++){ int offLED = i - 1; //Calculate which LED was turned on last time through if(i == 0) { //for i = 1 to 7 this is i minus 1 (i.e. if i = 2 we will offLED = 3; //turn on LED 2 and off LED 1) } //however if i = 0 we don't want to turn of led -1 (doesn't exist) //instead we turn off LED 7, (looping around) int onLED1 = 3 - i; //this is the first LED to go on ie. LED #3 when i = 0 and LED //#0 when i = 3 int onLED2 = 4 + i; //this is the first LED to go on ie. LED #4 when i = 0 and LED //#7 when i = 3 int offLED1 = 3 - offLED; //turns off the LED we turned on last time int offLED2 = 4 + offLED; //turns off the LED we turned on last time digitalWrite(ledPins[onLED1], HIGH); digitalWrite(ledPins[onLED2], HIGH); digitalWrite(ledPins[offLED1], LOW); digitalWrite(ledPins[offLED2], LOW); delay(delayTime); } //runs the LEDs into the middle for(int i = 3; i >= 0; i--){
    int offLED = i + 1;  //Calculate which LED was turned on last time through
    if(i == 3) {         //for i = 1 to 7 this is i minus 1 (i.e. if i = 2 we will
      offLED = 0;        //turn on LED 2 and off LED 1)
    }                    //however if i = 0 we don't want to turn of led -1 (doesn't exist)
                         //instead we turn off LED 7, (looping around)
    int onLED1 = 3 - i;       //this is the first LED to go on ie. LED #3 when i = 0 and LED 
                             //#0 when i = 3 
    int onLED2 = 4 + i;       //this is the first LED to go on ie. LED #4 when i = 0 and LED 
                             //#7 when i = 3 
    int offLED1 = 3 - offLED; //turns off the LED we turned on last time
    int offLED2 = 4 + offLED; //turns off the LED we turned on last time
    
    digitalWrite(ledPins[onLED1], HIGH);
    digitalWrite(ledPins[onLED2], HIGH);    
    digitalWrite(ledPins[offLED1], LOW);    
    digitalWrite(ledPins[offLED2], LOW);        
    delay(delayTime);
  }
}

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