// manually define all the An ports on ESP32 board
#if defined(ESP32)
#define A0       (36)
#define A1       (39)
#define A2       (34)
#define A3       (35)
#define A4       (32)
#define A5       (33)
#endif

// define the divident of sizeof()'s return value
#if defined(ESP32)
#define SIZE_DIV 4  // for esp32, the resolution is doubled than the usual arduino board, so we double the factor, too
#else
#define SIZE_DIV 2
#endif
#define WAIT_TIME  1000UL
#define SENSOR1    36
// FILE *f = fopen("file.txt", "w");
int pins[] = {A0, A1, A2, A3, A4, A5};
int i, j;
unsigned long currTime;  // non-blocking time tracker

void setup() {
  Serial.begin(19200);
  currTime = millis();
  analogReadResolution(12);
  // adcAttachPin(A0);
  // analogSetClockDiv(255);
  
}

void loop() {
  // we might need analogSetAttenuation to make the measurement more accurate and less noisy?
  if (millis() - currTime >= WAIT_TIME) {  // non-blocking time delay
    // Serial.println();
    Serial.print("[");
    for (i = 0; i < sizeof(pins)/SIZE_DIV; i++) {

      // float volts = analogRead(pins[i]);
      // float result = volts * 3.3 / 4095;
      // Serial.print(result);

      float volts = analogReadMilliVolts(pins[i]);
      Serial.print(volts);
      // Serial.print(61319 * (3.3/volts - 1));
      if (i != sizeof(pins)/SIZE_DIV - 1) {
        Serial.print(", ");
      }
  
    }
    Serial.println("]");
    // Serial.println(analogReadMilliVolts(SENSOR1));
    currTime = millis();    
  }
  
}