#define PB1 10
#define Led1 7
int period = 2000;  //periode in ms
unsigned long time_now = 0;
bool button_pressed = false;

void setup() {
  Serial.begin(9600);
  pinMode(PB1, INPUT);
  pinMode(Led1, OUTPUT);
}

void loop()
{
  if (digitalRead(PB1))
  {
    if (!button_pressed) time_now = millis();
    button_pressed = true;

    if (millis() - time_now > period)
    {
      digitalWrite(Led1, HIGH);
      time_now = millis();
    }
  } else
  {
    digitalWrite(Led1, LOW);
    button_pressed = false;
  }
}