step motor

https://atceiling.blogspot.com/2013/04/arduino.html
https://www.youtube.com/watch?v=GyEa5MPJw_A

int apin=8;
int bpin=9;
int cpin=10;
int dpin=11;
int delaytime=10;
void setup()
{
  // put your setup code here, to run once:
  pinMode(apin,OUTPUT);
  pinMode(bpin,OUTPUT);
  pinMode(cpin,OUTPUT);
  pinMode(dpin,OUTPUT);
}

void loop()
{
  // put your main code here, to run repeatedly:
  digitalWrite(apin,HIGH);delay(delaytime);digitalWrite(apin,LOW);
  digitalWrite(bpin,HIGH);delay(delaytime);digitalWrite(bpin,LOW);
  digitalWrite(cpin,HIGH);delay(delaytime);digitalWrite(cpin,LOW);
  digitalWrite(dpin,HIGH);delay(delaytime);digitalWrite(dpin,LOW);
}