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    • Projects 1 >
      • 1.01: Blink
      • 1.02 Blink x2
      • 1.03 Blink Faster
      • 1.04 LED Chase!
      • 1.05 Wait To Blink
      • 1.06 Blink a Little Faster Now
      • 1.07 LED Fade
      • 1.08 RGB Blink
      • 1.09 Change RGB Color with SW1
      • 1.10 Fade RGB Colors
      • 1.11 Reaction Time Game
    • Projects 2 >
      • 2.01 Hello World
      • 2.02 Talk Back
      • 2.03 ASCII Values
      • 2.04 Ski Game
      • 2.05 Demonstration of the String Object
    • Projects 3 >
      • 3.01 Read the Potentiometer
      • 3.02 ASCIIbet Soup
      • 3.03 Potentiometer sets LED Brightness
      • 3.04 Potentiometer Sets Blink Rate
      • 3.05 LED Chase, Part II
    • Projects 4 >
      • 4.01 Bringing the Piezo to Life
      • 4.02 Controlling the Piezo with a Function
      • 4.03 Piezo C Major
      • 4.04 Piezo Greensleaves
      • 4.05 Piezo Metronome
      • 4.06 Piezo as an Input
      • 4.07 Piezo as an Input 2
      • 4.08 Metronome II
      • 4.09 Piezo Playback
      • 4.10 Piezo Fireworks
      • 4.11 Piezo Mosquito
    • Projects 5 >
      • 5.01 The Phototransistor
      • 5.02 Light and Sound
      • 5.03 Light and Sound II
    • Projects 6 >
      • 6.01 EEPROM
      • 6.02 I2C Address Scan
      • 6.03 Read the I2C Temperature Sensor
      • 6.04 High Temperature Alarm
    • Projects 7 >
      • 7.01 Arno Phone Home
      • 7.02 Keyboard Alphabet
      • 7.03 Move Mouse
      • 7.04 Draw Squares
    • Special Projects >
      • Bike Light Demo
  • References
    • Arno Pin Key
    • Arno Schematic
    • Project Index

Project 3.03 Potentiometer sets LED Brightness

 Now that we’re able to read the value of the thumbwheel potentiometer, we can use it to control any of the outputs on the Arno.  In this project, we use it to set the brightness of the red channel of the RGB LED.


Concepts:  ADC, analogRead, analogWrite

Circuits:
  • Circuit 3
  • Circuit 7


  • Select Sketch

    ///////////////////////////////////////////////////
    //Project 3.03
    //use potentiometer output to set redLED brightness
    int POT1 = A0;
    int potRead = 0;
    int redLED = 9;
    void setup(){
    pinMode(redLED,OUTPUT);
    pinMode(POT1,INPUT);
    }
    void loop(){
    potRead = analogRead(POT1);
    analogWrite(redLED,potRead/4);
    delay(100);
    }
    ///////////////////////////////////////////////////

    Instead of using a function like map, we simply divide the value of the potentiometer by 4 so that it fits within the range used by analogWrite:

      analogWrite(redLED,potRead/4);

    Back to Projects 3

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