#include <LiquidCrystal.h>

const int POT_R_PIN = A0;
const int POT_G_PIN = A1;
const int POT_B_PIN = A2;
const int POT_BRIGHTNESS_PIN = A3;
const int LED_R_PIN = 3;
const int LED_G_PIN = 5;
const int LED_B_PIN = 6;

LiquidCrystal lcd(13, 12, 11, 10, 9, 8);

void setup() {
  Serial.begin(115200);
  lcd.begin(16, 2);
  pinMode(LED_R_PIN, OUTPUT);
  pinMode(LED_G_PIN, OUTPUT);
  pinMode(LED_B_PIN, OUTPUT);
}

void loop() {
  byte r = map(analogRead(POT_R_PIN), 0, 1023, 0, 255);
  byte g = map(analogRead(POT_G_PIN), 0, 1023, 0, 255);
  byte b = map(analogRead(POT_B_PIN), 0, 1023, 0, 255);
  byte brightness = map(analogRead(POT_BRIGHTNESS_PIN), 0, 1023, 0, 255);

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("RGB= ");
  lcd.print(r);
  lcd.print(",");
  lcd.print(g);
  lcd.print(",");
  lcd.print(b);
  lcd.setCursor(0,1);
  lcd.print("Brightness: ");
  lcd.print(brightness);

  Serial.print("Brightness: ");
  Serial.print(brightness);
  Serial.print(" [R,G,B]={");
  Serial.print(r);
  Serial.print(", ");
  Serial.print(g);
  Serial.print(", ");
  Serial.print(b);
  Serial.print("} hex {0x");
  Serial.print(r, HEX);
  Serial.print(", 0x");
  Serial.print(g, HEX);
  Serial.print(", 0x");
  Serial.print(b, HEX);
  Serial.println("}");

  r = (byte)(((uint16_t)r*brightness) / 255);
  g = (byte)(((uint16_t)g*brightness) / 255);
  b = (byte)(((uint16_t)b*brightness) / 255);

  analogWrite(LED_R_PIN, r);
  analogWrite(LED_G_PIN, g);
  analogWrite(LED_B_PIN, b);
  delay(200);
}