/*control LED brightness*/
// constants won't change
#define LIGHT_SENSOR_PIN 13 // ESP32 pin GPIO13 connected to light sensor
#define LED_PIN 22 // ESP32 pin GPIO22 connected to LED
#define ANALOG_THRESHOLD 500
void setup() {
 pinMode(LED_PIN, OUTPUT); // set ESP32 pin to output mode
} 
void loop() {
 int analogValue = analogRead(LIGHT_SENSOR_PIN); // read the value on analog pin
 if (analogValue < ANALOG_THRESHOLD)
 digitalWrite(LED_PIN, HIGH); // turn on LED
 else
 digitalWrite(LED_PIN, LOW); // turn off LED
}