const int flexPin = A0;

float vref = 3.3;
int adcMax = 4095;

void setup() {

  Serial.begin(115200);

  Serial.println("Flex Sensor Reading");

}

void loop() {

  // Leer sensor
  int rawValue = analogRead(flexPin);

  // Convertir a voltaje
  float voltage = (rawValue * vref) / adcMax;

  // Mostrar datos
  Serial.print("Raw: ");
  Serial.print(rawValue);

  Serial.print(" | Voltage: ");
  Serial.print(voltage, 5);

  Serial.println(" V");

  delay(200);
}