https://dev.hackster.io/amal-
shaji/reading-the-encoder-value-
of-n20-motor-using-esp32-56575a

#define EncoderPinA 18
#define EncoderPinB 21
#define ForwardPin 27
#define BackwardPin 26
#define EnablePin 25
volatile long Encodervalue=0;
void setup() {
  pinMode(ForwardPin,OUTPUT);
  pinMode(BackwardPin,OUTPUT);
  pinMode(EnablePin,OUTPUT);
  pinMode(EncoderPinA, INPUT);
  pinMode(EncoderPinB, INPUT);
  
attachInterrupt(digitalPinToInterr
upt(EncoderPinA), updateEncoder, 
RISING);
  Serial.begin(9600);
}

void loop() {
    digitalWrite(ForwardPin,HIGH);
    digitalWrite(BackwardPin,LOW);
    analogWrite(EnablePin,255);
    
    Serial.println(Encodervalue);
    delay(100);
    
}

void updateEncoder()
{
  if (digitalRead(EncoderPinA)> 
digitalRead(EncoderPinB))
    Encodervalue++;
  else
    Encodervalue--;
}