const int l1=13;
int td=1000;
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(l1, OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
if(td<=0){
td=1000;
}
else if (td<550){
td=td-250;
}
else {
td=td-100;
}
digitalWrite(l1, HIGH);
Serial.println(td);
delay(td);
digitalWrite(l1, LOW);
Serial.println(td);
delay(td);
}