Driving Multiple LEDs with an Arduino

I have had a bunch of white LEDs in my Amazon shopping cart for quite some time. I was tossing around the idea of doing a 5×5 cube a while ago, but ran out of steam on that project. I blame the PowerSwitch Tail…I had relays on the brain, big time. Still drafting out my big project on that front; stay tuned for some sweet garage door action. I rarely find my self with two projects in flight, that may actually turn into something, but I just might have stumbled back into the LED arena.

Long story short, I had my Arduino, Mini 9, some white LEDs, and exactly seven jumper wires in my backpack. I stepped upstairs at work for lunch, and decided to horse around with them…see what it takes to run multiple LEDs. Seems basic, and it is. Fortunately…

Here is he setup…

six shooter

not much to it

I put together a little sketch. I managed to grab the time-stamp notion from this sketch that is included with the IDE, and run with the rest of it. There will be snippet, but snippet will follow A SWEET VIDEO FTW

Video / snippet / wrap-up after the bump


//LED Sandbox

// Joseph Swanson | 2011
// http://swantron.com

// Setup… LEDs connected to digi 1-6, grounded

// Pin assignment
const int ledPin1 = 1;
const int ledPin2 = 2;
const int ledPin3 = 3;
const int ledPin4 = 4;
const int ledPin5 = 5;
const int ledPin6 = 6;

// Create variables to store LED states
int ledState1 = LOW;
int ledState2 = LOW;
int ledState3 = LOW;
int ledState4 = LOW;
int ledState5 = LOW;
int ledState6 = LOW;

// Create timestamp holder

long timeStore1 = 0;
long timeStore2 = 0;
long timeStore3 = 0;
long timeStore4 = 0;
long timeStore5 = 0;
long timeStore6 = 0;

// Configure interval for off/on
long interval1 = 600;
long interval2 = 800;
long interval3 = 1000;
long interval4 = 600;
long interval5 = 800;
long interval6 = 1000;

void setup() {

//Define pins 1-6 as output
pinMode(ledPin1, OUTPUT);
pinMode(ledPin2, OUTPUT);
pinMode(ledPin3, OUTPUT);
pinMode(ledPin4, OUTPUT);
pinMode(ledPin5, OUTPUT);
pinMode(ledPin6, OUTPUT);


void loop()
// Loop area…compare config for time to current
// time…write when config time is reached
if (millis() – timeStore1 > interval1) {
// re-write timestore
timeStore1 = millis();

// if the LED is off turn it on and vice-versa:
if (ledState1 == LOW)
ledState1 = HIGH;
ledState1 = LOW;}

if (millis() – timeStore2 > interval2) {
// re-write timestore
timeStore2 = millis();

if (ledState2 == LOW)
ledState2 = HIGH;
ledState2 = LOW; }

if (millis() – timeStore3 > interval3) {
// re-write timestore
timeStore3 = millis();

if (ledState3 == LOW)
ledState3 = HIGH;
ledState3 = LOW; }

if (millis() – timeStore4 > interval4) {
// re-write timestore
timeStore4 = millis();

if (ledState4 == LOW)
ledState4 = HIGH;
ledState4 = LOW; }

if (millis() – timeStore5 > interval5) {
// re-write timestore
timeStore5 = millis();

if (ledState5 == LOW)
ledState5 = HIGH;
ledState5 = LOW; }

if (millis() – timeStore6 > interval6) {
// re-write timestore
timeStore6 = millis();

if (ledState6 == LOW)
ledState6 = HIGH;
ledState6 = LOW; }

// digi-write LED state
digitalWrite(ledPin1, ledState1);
digitalWrite(ledPin2, ledState2);
digitalWrite(ledPin3, ledState3);
digitalWrite(ledPin4, ledState4);
digitalWrite(ledPin5, ledState5);
digitalWrite(ledPin6, ledState6);


So, I configured the times to have bulbs one and four blast at 6/10ths of a second, two and five to go at 8/10ths, and three and six to blink every second. Pretty boring, huh. The next plan is to bump that number to 8 LEDs and put together a little binary timer. Then learn how to drive multiple LEDs from the same pin. After that…who knows. I can do whatever I feel like doing, really.

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