Sample Code for Arduino Programming Basics Class

analogWrite.ino

// Sample Code for Arduino Programming Basics Class
// Matt Richardson http://mattrichardson.com/

// With this code, use a button to try out analogWrite.
// It will dim an LED when you press it.

// Wire up a button to digital pin 2:
#define BUTTON_PIN 2

// Wire up an LED to pin 3:
#define GREEN_LED 3

// Everything in the setup() function runs once when the Arduino starts up.
void setup() { 
  pinMode(GREEN_LED, OUTPUT); // Set the LED pin to digital output.
  pinMode(BUTTON_PIN, INPUT); // Set the button to digital input.
}

// Everything in the loop() function runs over and over again after setup() is finished.
void loop() { 
  if (digitalRead(BUTTON_PIN) == HIGH) { // Is the button pressed?
    analogWrite(GREEN_LED, 10); // then make the LED dim.
  }
  else {                        // Otherwise,
    analogWrite(GREEN_LED, 255); // make the LED bright.
  }
}

int-AnalogRead.ino

// Sample Code for Arduino Programming Basics Class
// Matt Richardson http://mattrichardson.com/

// With this code, use a potentiometer (dial) to activate
// three LEDs and write the value via serial.

// Wire up a button to digital pin 2:
#define BUTTON_PIN 2

// Wire up three LEDs to digital pins 3, 4, and 5:
#define GREEN_LED 3
#define YELLOW_LED 4
#define RED_LED 5

// Wire up a potentiometer to analog input pin 0:
#define POTENTIOMETER 0

// Create a new variable with the type integer, call it value,
// and set it to zero.
int value = 0;

// Everything in the setup() function runs once when the Arduino starts up.
void setup() { 
  // Set the LED pins to digital output:
  pinMode(GREEN_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);

  // Set the button to digital input:
  pinMode(BUTTON_PIN, INPUT);

  // Set up the serial communication at 115200 baud:
  Serial.begin(115200);
}

// Everything in the loop() function runs over and over
// again after setup() is finished.
void loop() { 
  // Take the reading from the potentiometer's analog input pin,
  // and store it in the variable value:
  value = analogRead(POTENTIOMETER);

  // Remap the value, which had the range 0 - 1023 to 0 - 100:
  value = map(value, 0, 1023, 0, 100);

  // Print the number stored in value to serial:
  Serial.println(value);

  if (value > 25 ) { // is value greater than 25?
    digitalWrite(GREEN_LED, HIGH); // then turn the green LED on.
  }
  else { // otherwise, turn it off.
    digitalWrite(GREEN_LED, LOW); 
  }

  if (value > 50) { // is value greater than 50?
    digitalWrite(YELLOW_LED, HIGH); // then turn the yellow LED on.
  }
  else {
    digitalWrite(YELLOW_LED, LOW); // otherwise, turn it off.
  }

  if (value > 75) { // is value greater than 75?
    digitalWrite(RED_LED, HIGH); // then turn the red LED on.
  }
  else {
    digitalWrite(RED_LED, LOW); // otherwise turn it off.
  }
}

LEDFade-ForLoop.ino

// Sample Code for Arduino Programming Basics Class
// Matt Richardson http://mattrichardson.com/

// With this code, make an LED fade up and down using a
// for loop!

// Wire up an LED to pin 3 (or any PWM pin, they're marked with a ~)
#define GREEN_LED 3

// Everything in the setup() function runs once when the Arduino starts up.
void setup() {
  pinMode(GREEN_LED, OUTPUT); // set the LED pin to an output.
}

// Everything in the loop() function runs over and over
// again after setup() is finished.
void loop() {
  // syntax: for (INITIALIZER, CONDITION, AFTERTHOUGHT) { CODE }
  // pseudocode: At the start of this loop, set up a spot in memory called i
  //       and set it to 0. Run this loop as long as i is less than or equal to 255.
  //        At the end of every iteration, increment i by one.
  // This will fade the LED up slowly:
  for (int i = 0; i <= 255 ; i++) {
    analogWrite(GREEN_LED, i); // analog write the value of i to the green LED.
    delay(5); // slow things down a touch.
  }

  // When that loop is done, go into the next loop to fade the LED down slowly:
  for (int j = 255; j > 0; j--) {
    analogWrite(GREEN_LED, j);
    delay(5);
  }

}