LED Arduino

This circuit uses Arduino to light 13 LED's in a way that it looks like they charge/discharge the central, blue LED.

int ledPins[] = {1,2,3,4,5,6,7,8,9,10,11,12,13};//n 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 < 13; 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(); t 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 = 200; //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 digitalWrite(ledPins[8], HIGH); //Turns on LED #1 (connected to pin 3 ) delay(delayTime); digitalWrite(ledPins[9], HIGH); //Turns on LED #1 (connected to pin 3 ) delay(delayTime); digitalWrite(ledPins[10], HIGH); //Turns on LED #1 (connected to pin 3 ) delay(delayTime); digitalWrite(ledPins[11], HIGH); //Turns on LED #1 (connected to pin 3 ) delay(delayTime); digitalWrite(ledPins[12], HIGH); //Turns on LED #1 (connected to pin 3 ) delay(delayTime); //Turns Each LED Off digitalWrite(ledPins[12], LOW); delay(delayTime); digitalWrite(ledPins[11], LOW); delay(delayTime); digitalWrite(ledPins[10], LOW); delay(delayTime); digitalWrite(ledPins[9], LOW); delay(delayTime); digitalWrite(ledPins[8], LOW); delay(delayTime); 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 <= 12; 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 = 12; 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 <= 12; 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 = 12; //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(50); } } /* * 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 <= 6; 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 = 6; //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 = 6 - i; //this is the first LED to go on ie. LED #3 when i = 0 and LED //#0 when i = 3 int onLED2 = 7 + i; //this is the first LED to go on ie. LED #4 when i = 0 and LED //#7 when i = 3 int offLED1 = 6 - offLED; //turns off the LED we turned on last time int offLED2 = 7 + 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 = 5; i >= 0; i--){ int offLED = i + 1; //Calculate which LED was turned on last time through if(i == 5) { //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 =5 - i; //this is the first LED to go on ie. LED #3 when i = 0 and LED //#0 when i = 3 int onLED2 = 6 + i; //this is the first LED to go on ie. LED #4 when i = 0 and LED //#7 when i = 3 int offLED1 = 5 - offLED; //turns off the LED we turned on last time int offLED2 = 6 + 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); } }

Building the circuit is quite simple. Attach the LED's positive end to one of the input pins, and the negative pin to a resistor (we used a 560 Ohm resistor) that goes to ground. Repeat this setup 12 more times to get the same number of resistors that we used.