https://www.tinkercad.com/things/0UIHZ8vmQ1d-start-simulating/editel?lessonid=EHD2303J3YPUS5Z&projectid=OIYJ88OJ3OPN3EA&collectionid=OIYJ88OJ3OPN3EA&tenant=circuits#/lesson-viewer?sharecode=x_UukBJ2BlqMUS-sHPRXNPcjNtv9lO-RbWwYgqYj-ng

thermal-fishing-tinkercad.ino

/*
 * Thermal fishing
 * https://www.circuitbasics.com/arduino-thermistor-temperature-sensor-tutorial/
 */
 
// Pins 3, 5, and 6 are the red, green and blue LEDs on the Arduino board.
// give them names:
int redPin = 3;
int greenPin = 5;
int bluePin = 6;
int thermistorPin = 1;
int thermistorValue;
int startVal;

void setup() {
  // start with current ambient temp = blue/cold
  startVal = analogRead(thermistorPin); // 0-1023
}

// the loop routine runs over and over again forever:
void loop() {
  thermistorValue = analogRead(thermistorPin); // 0-1023

  int hue = map(thermistorValue, startVal, startVal + 4, 250, 0); // map it to 0-360

  Serial.print(thermistorValue);
  Serial.print(" - ");
  Serial.println(hue);
  setLedColorHSV(hue, 1, 1);

}



// http://www.hobbitsandhobos.com/wp-content/uploads/2011/06/colorWheel.png
// Convert a given HSV (Hue Saturation Value) to RGB (Red Green Blue)
// and set the led to the color
//  h is hue value, integer between 0 and 360
//  s is saturation value, double between 0 and 1
//  v is value, double between 0 and 1
// http://splinter.com.au/blog/?p=29
void setLedColorHSV(int h, double s, double v) {
  
  double r=0; 
  double g=0; 
  double b=0;

  double hf=h/60.0;

  int i=(int)floor(h/60.0);
  double f = h/60.0 - i;
  double pv = v * (1 - s);
  double qv = v * (1 - s*f);
  double tv = v * (1 - s * (1 - f));

  switch (i)
  {
  case 0: // rojo dominante
    r = v;
    g = tv;
    b = pv;
    break;
  case 1: // verde
    r = qv;
    g = v;
    b = pv;
    break;
  case 2: 
    r = pv;
    g = v;
    b = tv;
    break;
  case 3: // azul
    r = pv;
    g = qv;
    b = v;
    break;
  case 4:
    r = tv;
    g = pv;
    b = v;
    break;
  case 5: // rojo
    r = v;
    g = pv;
    b = qv;
    break;
  }

  // set each component to a integer value between 0 and 255
  int red = constrain(255-(int)255*r,0,255);
  int green = constrain(255-(int)255*g,0,255);
  int blue = constrain(255-(int)255*b,0,255);

  setLedColor(red,green,blue);
}

void setLedColor(int red, int green, int blue) {
  analogWrite(redPin,   red);
  analogWrite(greenPin, green);
  analogWrite(bluePin,  blue);
}