/*control led brightness */
#define POTENTIOMETER_PIN 35 // ESP32 pin GPIO35 (ADC0) connected to Potentiometer pin
#define LED_PIN 26 // ESP32 pin GPIO26 connected to LED's pin
// the setup routine runs once when you press reset:
void setup() {
 // initialize serial communication at 9600 bits per second:
 Serial.begin(9600); 
 // declare LED pin to be an output:
 pinMode(LED_PIN, OUTPUT); 
} 
// the loop routine runs over and over again forever:
void loop() {
 // reads the input on analog pin A0 (value between 0 and 4095)
 int analogValue = analogRead(POTENTIOMETER_PIN); 
 // scales it to brightness (value between 0 and 255)
 int brightness = map(analogValue, 0, 4095, 0, 255); 
 // sets the brightness LED that connects to pin 3
 analogWrite(LED_PIN, brightness);
 // print out the value
 Serial.print("Analog value = "); 
 Serial.print(analogValue);
 Serial.print(" => brightness = "); 
 Serial.println(brightness);
 delay(100); 
}