#include <AccelStepper.h>
AccelStepper stepper(1, 12, 11);
int but = 10;
int relay = 2;

void setup() {
  pinMode(but, INPUT);
  pinMode(relay, OUTPUT);
  stepper.setMaxSpeed(4000);
  Serial.begin(9600);
}

void loop() {
  stepper.setSpeed(500);
  stepper.runSpeed();
  if (digitalRead(but) == HIGH) {
    digitalWrite(relay, HIGH);
    Serial.print("Motor On\n");
  }
  else {
    Serial.print("Motor Off\n");
    digitalWrite(relay, LOW);
  }
}