Программный триггер с фильтром дребезга

[Urvin]

unsigned char button_state;
unsigned char old_button_state;

#define BUTTON_PIN 0
#define RELAY_PIN 1
void setup()
{
    button_state = digitalRead(BUTTON_PIN);
    trigger_relay = 0;
}
void loop()
{
    button_state = digitalRead(BUTTON_PIN);

    if (button_state != old_button_state)
    {
        if (button_state == 0)
        {
            if (digitalRead(RELAY_PIN) == 1) digitalWrite(RELAY_PIN, 0);
            else digitalWrite(RELAY_PIN, 1);
        }

        old_button_state = button_state;
    }
}