int cambien = 3;
int relay1 = 2;
int relay2 = 4;
int gtcb;
unsigned long timer;
int votay;
void setup() {
  Serial.begin(9600);
  pinMode(cambien, INPUT);
  pinMode(relay1, OUTPUT);
  pinMode(relay2,OUTPUT);
  gtcb = 0;
  timer =0;
}

void loop() {
gtcb = digitalRead(cambien);
Serial.print("Giá trị cảm biến 1: " );
Serial.println(gtcb);

votay = 0;
  if(gtcb == 1)
  {
    timer = millis();
    votay++;
    //delay(200);
    while(millis()-timer <2000)
    {
      gtcb = digitalRead(cambien);
      Serial.print("Giá trị cảm biến 2: " );
      Serial.println(gtcb);
     if(gtcb == 1)
     {
       votay++;
       delay(200);
     }
    }
  }
  Serial.print("Vỗ tay : " );
  Serial.print(votay );
  Serial.println(" lần");
  if(votay == 1)
  {
    digitalWrite(relay1,LOW);
    delay(500);

  }
  if(votay == 2)
  {
    digitalWrite(relay1,HIGH);
    delay(500);

  }

}