#include <Stepper.h>

float ile = 50; //speed min 2

Stepper PAN(8, 8, 10, 9, 11);

//char znak;
unsigned znak;

int x = 1;
unsigned y = 1;

void setup(){


  Serial.begin(9600);

}

void loop(){

if(Serial.available()){
   String value = Serial.readStringUntil('\n');
  // Serial.println(value);
   if(value == "a")//zwalnianie
   ile=ile+1;
    if(value == "b")//przyspieszanie
   ile=ile-1;
    Serial.println(ile);
  }
PAN.step(1);
delay(ile);
}