void setup() {

// put your setup code here, to run once:
Serial. begin(115200) ;
if(!Serial) Serial. println("serial is not ok") ;
pinMode(16, OUTPUT);
pinMode(17, OUTPUT);
pinMode(18, OUTPUT);
pinMode(19, INPUT);
}


void loop() {
int switcher=digitalRead(19);
if (switcher==1)
{
digitalWrite(16, HIGH);
Serial.println("STOP");
delay(5000);
digitalWrite(16, LOW);
digitalWrite(17, HIGH);
Serial.println("LOOK");
delay(2000);
digitalWrite(17, LOW);
digitalWrite(18, HIGH);
Serial.println("GO");
delay(5000);
digitalWrite(18, LOW);
digitalWrite(17, HIGH);
Serial.println("LOOK");
delay(2000);
digitalWrite(17, LOW);
}
else
{
  digitalWrite(16, LOW);
  digitalWrite(17, LOW);
  digitalWrite(18, LOW);
}
}