#define led_red 13
#define pb_1 12

boolean last_stat = HIGH;
boolean current_stat = HIGH;
boolean led_stat  = LOW;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(led_red, OUTPUT);
  pinMode(pb_1, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
  current_stat = digitalRead(pb_1);
  if(current_stat == LOW && last_stat == HIGH){
    led_stat = !led_stat;
    digitalWrite(led_red, led_stat);
  }
  last_stat = current_stat;
  delay(10);
}