void setup() {
  pinMode(7, OUTPUT);//wheel
  pinMode(2, INPUT);
  Serial.begin(9600);
}

void loop() {


  int a;
  a=digitalRead(2);//reading the value of senor
  Serial.println("a value:");
  Serial.println(a);
  delay(1000);

if (a==1){
  digitalWrite(7,LOW);
}
else{
  digitalWrite(7, HIGH);
}
}