In this demo I wanted to understand how an analog tool, such as a soft potentiometer could change the color of an RGB Led. I also made an attempt to connect sound through the use of a piezo buzzer in association with a change in the color, but was unsuccessful in the output.

In the demo video the RGB led is not visible. To optimize the ability to notice the change in color I placed a foam cube on top of the led to slow the diffusion of the light.

The circuit was created with help from a few websites noted in the code below.

// Help from SparkFun guide to use of a soft potentiometer and HackerScapes
Buzzer Reacts to a Specific RGB LED Color


//Create a system where a spectrasymbol soft potentiometer changes the color of an RGB light.
// setup pins for rgb color constants (Digital Pins)

 

const int SoftPotentiometer_PIN = 0; // Analog input pin a0

const int RED_COLOR= 8;
const int GREEN_COLOR= 9;
const int BLUE_COLOR= 10;

int PIEZO_sound = 12;
int PIEZO_value = 0;

// Global variables for Pulse with Modulation values of the RGB LED.For interpretation in the rgb function and loop.
//PWM controls the LED brightness, the color becomes mixed when dimming in different amounts.
int redValue, greenValue, blueValue;

void setup()
{
pinMode(RED_COLOR, OUTPUT);
pinMode(GREEN_COLOR, OUTPUT);
pinMode(BLUE_COLOR , OUTPUT);
pinMode(PIEZO_value, OUTPUT);

Serial.begin(9600); // serial communication at bits/second
}

 

void loop()
{
// Soft Potentiometer Value, analog input value ranges from (0-1023)
int pValue;

pValue = analogRead(SoftPotentiometer_PIN);

setRGB(pValue); // set the rgb led color to potentiometer value

// or &gt for (>) and &lt(<) / &amp ... syntax???
// some reason the syntax below did not create an "not declared" error message.
if (pValue > 0 , pValue <=200)
{
digitalWrite(PIEZO_value,HIGH);// turn on piezo buzzer sound
}
else:
digitalWrite(PIEZO_value, LOW); // if minimum voltage not recieved or larger, no sound from the piezo buzzer.
}

// begin setting up sections of the potentiometer for different color "peaks."
void setRGB(int RGBposition)
{
int mapRGB1, mapRGB2, constrain1, constrain2;

// (Red at 0 and the midpoint)

mapRGB1 = map(RGBposition, 0, 341, 255, 0);
constrain1 = constrain(mapRGB1, 0, 255);

mapRGB2 = map(RGBposition, 682, 1023, 0, 255);
constrain2 = constrain(mapRGB2, 0, 255);

redValue = constrain1 + constrain2;

// Green at 341
// (one-third of the way to 1023):

greenValue = constrain(map(RGBposition, 0, 341, 0, 255), 0, 255)
- constrain(map(RGBposition, 341, 682, 0,255), 0, 255);

// Blue at 682
// (two-thirds of the way to 1023):

blueValue = constrain(map(RGBposition, 341, 682, 0, 255), 0, 255)
- constrain(map(RGBposition, 682, 1023, 0, 255), 0, 255);

analogWrite(RED_COLOR, redValue);
analogWrite(GREEN_COLOR, greenValue);
analogWrite(BLUE_COLOR, blueValue);

}