The GIFt of Light

SAM: William ... come see thine latest creation

WILLIE: Ser Samuel what discovery of wonder and creation of magic hath you delivered here today?!

S: It ish a curcuit my simple friend. One that uses both the simple LED circuitry I have shown you previously and a three-post variable potentiometer -- a dial, Ser William -- to control the brightness of said light.

W: fffaassssssccinating Samuel

S: But there is more! As I control this system and output feed is transfered back to my computer operating system, displaying to me the changes in intensity  and resistance of energy.

W: I am frozen in a state of amazement! 

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Below is a GIF of 

a) the process in motion 

b) sam represents what the LED is doing

c) willie represents what the dial is doing to control the LED

d) a gif of hands to represent the motion of electrons in our circuit

Our Code looks like this:

/*

  Analog input, analog output, serial output

 Reads an analog input pin, maps the result to a range from 0 to 255

 and uses the result to set the pulsewidth modulation (PWM) of an output pin.

 Also prints the results to the serial monitor.

 The circuit:

 * potentiometer connected to analog pin 0.

   Center pin of the potentiometer goes to the analog pin.

   side pins of the potentiometer go to +5V and ground

 * LED connected from digital pin 9 to ground

 created 29 Dec. 2008

 modified 9 Apr 2012

 by Tom Igoe

 This example code is in the public domain.

 */

// These constants won't change.  They're used to give names

// to the pins used:

const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to

const int analogOutPin = 9; // Analog output pin that the LED is attached to

int sensorValue = 0;        // value read from the pot

int outputValue = 0;        // value output to the PWM (analog out)

void setup() {

  // initialize serial communications at 9600 bps:

  Serial.begin(9600); 

}

void loop() {

  // read the analog in value:

  sensorValue = analogRead(analogInPin);            

  // map it to the range of the analog out:

  outputValue = map(sensorValue, 0, 1023, 0, 255);  

  // change the analog out value:

  analogWrite(analogOutPin, outputValue);           

  // print the results to the serial monitor:

  Serial.print("sensor = " );                       

  Serial.print(sensorValue);      

  Serial.print("\t output = ");      

  Serial.println(outputValue);   

  // wait 2 milliseconds before the next loop

  // for the analog-to-digital converter to settle

  // after the last reading:

  delay(2);                     

}