First we are going to look at flashing an LED, this is the 'hello world' of electronics. 

  • Open the Arduino environment
  • Go to the 'File' menu and open the 'Examples => 01.Basics => Blink' sketch.
  • Plug the Arduino board USB cable into your computer and hit the Upload button in the software (the arrow in a circle) 
  • Marvel as the on-board LED flashes!!

Lets do this properly and flash an LED on some breadboard. There are different types of breadboard

 

 

 

 

 

The original code for this example can be found here

RGB Mixer Circuit

/*
* Code for making one potentiometer control 3 LEDs, red, grn and blu, or one tri-color LED
* The program cross-fades from red to grn, grn to blu, and blu to red
* Clay Shirky <clay.shirky@nyu.edu> 
* 
* Adapted for common anode RGB LEDs by Luke Woodbury 
* 11th March 2016
*/

// INPUT: Potentiometer should be connected to 5V and GND
int potPin = 0; // Potentiometer output connected to analog pin 3
int potVal = 0; // Variable to store the input from the potentiometer

// OUTPUT: Use digital pins 9-11, the Pulse-width Modulation (PWM) pins
// LED's cathodes should be connected to digital GND
int redPin = 9;   // Red LED,   connected to digital pin 9
int grnPin = 10;  // Green LED, connected to digital pin 10
int bluPin = 11;  // Blue LED,  connected to digital pin 11

// Program variables
int redVal = 0;   // Variables to store the values to send to the pins
int grnVal = 0;
int bluVal = 0;

void setup()
{
  pinMode(redPin, OUTPUT);   // sets the pins as output
  pinMode(grnPin, OUTPUT);   
  pinMode(bluPin, OUTPUT);
  Serial.begin(9600); 
}

// Main program
void loop()
{
  potVal = analogRead(potPin);   // read the potentiometer value at the input pin

  if (potVal < 341)  // Lowest third of the potentiometer's range (0-340)
  {                  
    potVal = (potVal * 3) / 4; // Normalize to 0-255
//Serial.println(potVal);
    redVal = potVal;  // Red from full to off
    grnVal = 255 - potVal;        // Green from off to full
    bluVal = 255;             // Blue off
  }
   else if (potVal < 682) // Middle third of potentiometer's range (341-681)
  {
    potVal = ( (potVal-341) * 3) / 4; // Normalize to 0-255

    redVal = 255;            // Red off
    grnVal = potVal; // Green from full to off
    bluVal = 255 - potVal;       // Blue from off to full
  }
  else  // Upper third of potentiometer"s range (682-1023)
  {
    potVal = ( (potVal-683) * 3) / 4; // Normalize to 0-255

    redVal = 255 - potVal;       // Red from off to full
    grnVal = 255;            // Green off
    bluVal = potVal; // Blue from full to off
  }
  analogWrite(redPin, redVal);   // Write values to LED pins
  analogWrite(grnPin, grnVal); 
  analogWrite(bluPin, bluVal); 
  
}