Lab 03 – Color Switcher

Description:

For this lab, I wanted to play around with all of the options available to me. I began with the pot controlling the blinking rate, then added a potentiometer to control the fade. After working through a minor issue with the digitalOut vs. analogOut that prevented the fade from working properly with the blinking, I was able to figure out how to make the two potentiometers play nice with each other.

Then I decided that I wanted to use the third potentiometer to control the mapping between the three LEDs—to use the rotation as a signal for which LED should be lit and which should be dark. So I added the third potentiometer and then did some research (and used the serial monitor) to read what values were being output by that new pot. I then set four increments, and had each individual LED light up for the first three (low values would be red, mid-low values would be green, mid-high values would be blue). Then I set the highest value to map to having all three LEDs lit at the same time. By using the serial monitor to troubleshoot from the beginning, I was able to get it to work with a minimum of trouble. So my first pot controls the blink rate, my second pot controls the fade level, and the third pot controls which LEDs are lit.

circuit board and LEDs

Components:

  • Arduino Uno
  • Breadboard
  • 3 potentiometers
  • 3 LEDs (red, green, blue)
  • 3 220Ω resistors
  • jumper wires
  • USB cable
  • computer

Code:


// EXTRA CREDIT CODE: mapping a third potentiometer so that I can control individual LEDs to fire one at a time,
// or have all three fire at once (when third pot is maxed out)

int fadepotPin = A1; // Analog input pin that the fade potentiometer is attached to
int fadepotValue = 0; // value read from the fade pot
int blinkpotPin = A0; // Analog input pin that the blink potentiometer is attached to
int blinkpotValue = 0; // value read from the blink pot
int mappingPin = A2; // this will be the one that maps rotation to LED color
int mappingValue = 0; // initially set the rotational mapping value to zero
int redledPin = 11;
int greenledPin = 10;
int blueledPin = 9;

void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
// declare the led pins as output:
pinMode(redledPin, OUTPUT);
pinMode(blueledPin, OUTPUT);
pinMode(greenledPin, OUTPUT);
}

void loop() {
fadepotValue = analogRead(fadepotPin); // read the fade pot value
blinkpotValue = analogRead(blinkpotPin); // read the blink pot value
mappingValue = analogRead(mappingPin); // read the value on the mapping pot

// turn on only the LED(s) that correspond to the value of the third pot
// minimum value for blue, middle values for green, and max value for red
// then that will turn on the LEDs according to the fade value and blink value

// print the results to the serial monitor:
Serial.print("mappingValue = ");
Serial.print(mappingValue);
Serial.print("\n");

if (mappingValue < 255) {
analogWrite(redledPin, fadepotValue/4); // PWM the LED with the pot value (divided by 4 to fit in a byte)
delay(blinkpotValue); // delay by the blink pot value in milliseconds
digitalWrite(redledPin, LOW); // then blink the LEDs off
}
else if (mappingValue >= 255 and mappingValue <; 610) {
analogWrite(greenledPin, fadepotValue/4); // PWM the LED with the pot value (divided by 4 to fit in a byte)
delay(blinkpotValue); // delay by the blink pot value in milliseconds
digitalWrite(greenledPin, LOW); // then blink the LEDs off
}
else if (mappingValue >= 610 and mappingValue < 770) {
analogWrite(blueledPin, fadepotValue/4); // PWM the LED with the pot value (divided by 4 to fit in a byte)
delay(blinkpotValue); // delay by the blink pot value in milliseconds
digitalWrite(blueledPin, LOW); // then blink the LEDs off
}
else if (mappingValue >= 770) {
analogWrite(redledPin, fadepotValue/4); // PWM the LED with the pot value (divided by 4 to fit in a byte)
analogWrite(blueledPin, fadepotValue/4);
analogWrite(greenledPin, fadepotValue/4);
delay(blinkpotValue); // delay by the blink pot value in milliseconds
digitalWrite(redledPin, LOW); // then blink the LEDs off
digitalWrite(blueledPin, LOW);
digitalWrite(greenledPin, LOW);
}
delay(blinkpotValue); // pause before blinking back on (also allows loop to run and pots to be adjusted)
}

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