{"id":542,"date":"2010-05-08T11:48:18","date_gmt":"2010-05-08T19:48:18","guid":{"rendered":"http:\/\/owenmundy.com\/blog\/?p=542"},"modified":"2010-11-11T04:02:45","modified_gmt":"2010-11-11T12:02:45","slug":"fading-an-led-with-pwm-and-a-potentiometer","status":"publish","type":"post","link":"https:\/\/owenmundy.com\/blog\/2010\/05\/fading-an-led-with-pwm-and-a-potentiometer\/","title":{"rendered":"Fading an LED with PWM and a Potentiometer"},"content":{"rendered":"

<\/param><\/param><\/param><\/object><\/p>\n

Using a potentiometer and PWM on an Arduino to fade an LED.<\/p>\n

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

    Here is the schematic for the above project.
    \n\"\"<\/p>\n

    <\/param><\/param><\/param><\/object><\/p>\n

    Using PWM and a potentiometer to fade an LED and drive a stepper motor, powered by a Boarduino RBBB.<\/p>\n

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

      Using a potentiometer and PWM on an Arduino to fade an LED.   \/* POT to LED test -> by Owen Mundy March 11, 2010    from: http:\/\/itp.nyu.edu\/physcomp\/Labs\/AnalogIn —————————————————————*\/   int potPin = 0;    \/\/ Analog input pin that the potentiometer is attached to int potValue = 0;  \/\/ value read from the pot […]<\/p>\n

      Read More… from Fading an LED with PWM and a Potentiometer<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[35],"tags":[55,165,57,38,56],"class_list":["post-542","post","type-post","status-publish","format-standard","hentry","category-sketches","tag-arduino","tag-code","tag-electronics","tag-interactive","tag-physical-computing"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2ovQg-8K","_links":{"self":[{"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/posts\/542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/comments?post=542"}],"version-history":[{"count":15,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/posts\/542\/revisions"}],"predecessor-version":[{"id":551,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/posts\/542\/revisions\/551"}],"wp:attachment":[{"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/media?parent=542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/categories?post=542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/owenmundy.com\/blog\/wp-json\/wp\/v2\/tags?post=542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}