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Fading an LED with PWM and a Potentiometer

Using a potentiometer and PWM on an Arduino to fade an LED.

  1.  
  2. /* POT to LED test -> by Owen Mundy March 11, 2010
  3.    from: http://itp.nyu.edu/physcomp/Labs/AnalogIn
  4. —————————————————————*/
  5.  
  6. int potPin = 0;    // Analog input pin that the potentiometer is attached to
  7. int potValue = 0;  // value read from the pot
  8. int led = 9;      // PWM pin that the LED is on.  n.b. PWM 0 is on digital pin 9
  9.  
  10. void setup() {
  11.   // initialize serial communications at 9600 bps:
  12.   Serial.begin(9600);
  13.   // declare the led pin as an output:
  14.   pinMode(led, OUTPUT);
  15. }
  16.  
  17. void loop() {
  18.   potValue = analogRead(potPin); // read the pot value
  19.   analogWrite(led, potValue/4);  // PWM the LED with the pot value (divided by 4 to fit in a byte)
  20.   Serial.println("hello");      // print the pot value back to the debugger pane
  21.   delay(10);                     // wait 10 milliseconds before the next loop
  22. }
  23.  

Here is the schematic for the above project.

Using PWM and a potentiometer to fade an LED and drive a stepper motor, powered by a Boarduino RBBB.

  1.  
  2. /*
  3.   Owen Mundy
  4.  July 29, 2009
  5.  
  6.  p. 262 of Physical Computing
  7.  Using BBB to run stepper motor by manually moving steppers
  8.  
  9.  */
  10.  
  11. int pin1 = 3;                 // PWM
  12. int pin2 = 5;                 // PWM
  13. int pin3 = 6;                 // PWM
  14. int pin4 = 9;                 // PWM
  15. int ledpin = 13;              // LED
  16. int led = false;              // LED monitor
  17. int motor_time_lapse = 80;
  18.  
  19. int potPin = 0;      // Analog input pin that the potentiometer is attached to
  20. int potValue = 0;    // value read from the pot
  21. int ledPotPin = 11;  // PWM pin that the LED is on.  n.b. PWM 0 is on digital pin 9
  22.  
  23.  
  24. void setup()
  25. {
  26.   pinMode(pin1, OUTPUT);      // sets the pin as output
  27.   pinMode(pin2, OUTPUT);      // sets the pin as output
  28.   pinMode(pin3, OUTPUT);      // sets the pin as output
  29.   pinMode(pin4, OUTPUT);      // sets the pin as output
  30.   pinMode(ledpin, OUTPUT);    // sets the pin as output
  31.  
  32.   // initialize serial communications at 9600 bps:
  33.   Serial.begin(9600);
  34.   // declare the led pin as an output:
  35.   pinMode(ledPotPin, OUTPUT);
  36. }
  37.  
  38. void loop()
  39. {
  40.   potValue = analogRead(potPin); // read the pot value
  41.   analogWrite(ledPotPin, potValue/4);  // PWM the LED with the pot value (divided by 4 to fit in a byte)
  42.   Serial.println(potValue);
  43.  
  44.   digitalWrite(pin1, HIGH);   // on
  45.   digitalWrite(pin2, LOW);    // off
  46.   digitalWrite(pin3, HIGH);   // on
  47.   digitalWrite(pin4, LOW);    // off
  48.   delay(motor_time_lapse);    // wait
  49.  
  50.  
  51.   digitalWrite(pin1, LOW);    // off
  52.   digitalWrite(pin2, HIGH);   // on
  53.   digitalWrite(pin3, HIGH);   // on
  54.   digitalWrite(pin4, LOW);    // off
  55.   delay(motor_time_lapse);    // wait
  56.  
  57.   digitalWrite(pin1, LOW);    // off
  58.   digitalWrite(pin2, HIGH);   // on
  59.   digitalWrite(pin3, LOW);    // off
  60.   digitalWrite(pin4, HIGH);   // on
  61.   delay(motor_time_lapse);    // wait
  62.  
  63.  
  64.   digitalWrite(pin1, HIGH);   // on
  65.   digitalWrite(pin2, LOW);    // off
  66.   digitalWrite(pin3, LOW);    // off
  67.   digitalWrite(pin4, HIGH);   // on
  68.   delay(motor_time_lapse);    // wait
  69.  
  70.   blink();
  71. }
  72.  
  73. void blink()
  74. {
  75.   if (led == false)
  76.   {
  77.     led = true;
  78.     digitalWrite(ledpin, HIGH); // on  
  79.   }
  80.   else
  81.   {
  82.     led = false;
  83.     digitalWrite(ledpin, LOW); // on  
  84.   }
  85. }

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This entry was posted on Saturday, May 8th, 2010 at 11:48 am and is filed under sketches. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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