Code
int D7 = 7;int D6 = 6;int D5 = 5;int D4 = 4;
void setup()
{
pinMode(D7,OUTPUT);pinMode(D6,OUTPUT);
pinMode(D5,OUTPUT);pinMode(D4,OUTPUT);
}
void loop()
{
digitalWrite(D7,HIGH);digitalWrite(D6,LOW);
digitalWrite(D5,LOW);digitalWrite(D4,LOW);
delay(1000);
digitalWrite(D7,LOW);digitalWrite(D6,HIGH);
digitalWrite(D5,LOW);digitalWrite(D4,LOW);
delay(1000);
digitalWrite(D7,LOW);digitalWrite(D6,LOW);
digitalWrite(D5,HIGH);digitalWrite(D4,LOW);
delay(1000);
digitalWrite(D7,LOW);digitalWrite(D6,LOW);
digitalWrite(D5,LOW);digitalWrite(D4,HIGH);
delay(1000);
}