led control.ino

#include <Adafruit_DotStar.h>

// There is only one pixel on the board
#define NUMPIXELS 1 

//Use these pin definitions for the ItsyBitsy M4
#define DATAPIN    7
#define CLOCKPIN   8

Adafruit_DotStar strip(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);

void setup() {
  Serial.begin(9600);

  strip.begin(); // Initialize pins for output
  strip.setBrightness(80);
  strip.show();  // Turn all LEDs off ASAP
}

String lastLetter = "R";
void loop() {
  if (Serial && Serial.available()) {
    lastLetter = Serial.readStringUntil('\n');
    lastLetter.trim();
  }
  if (lastLetter == "G") {
    strip.setBrightness(80);
    strip.setPixelColor(0, strip.gamma32(strip.ColorHSV(0)));
    strip.show();
  } else if (lastLetter == "R") {
    strip.setBrightness(80);
    strip.setPixelColor(0, strip.gamma32(strip.ColorHSV(21846)));
    strip.show();    
  } else {
    strip.setBrightness(0);
    strip.show();
  }
  delay(100);
}