#include <AccelStepper.h>



int en = 10;
int in1 = 9;
int in2 = 8;
int in3 = 7;
int in4 = 6;

int fullstep = 4; 
int halfstep = 8; 
int stepdrive = fullstep; 

AccelStepper stepper1(1, 3, 2);

int steps = 200; 
long last = 0;
int lag = 500; 
int dir = 1; 
float rpm, v, oldspeed, a;
int nsteps;

void setup() {

  stepper1.setMaxSpeed(900); 
  stepper1.setAcceleration(900); 
  
  stepper1.moveTo(2000000000000000000000000);

}

void loop() {

  if (millis() > last + lag ) 
  {
    v = stepper1.speed(); 
    nsteps = v * lag / pow(10, 3); 
    rpm = 60.0 * v / steps; 
    a = (v - oldspeed) * 1000.0 / lag; 
    oldspeed = v;
    last = millis(); 
  }
  stepper1.run(); 
}