arduino按钮切换led状态：

arduino按钮切换led状态：

int LED=13;
int BUTTON=3;

int val=0;
int old_val=0;
int state=0;



void setup() {
    
    
  // put your setup code here, to run once:
  pinMode(LED,OUTPUT);
  pinMode(BUTTON,INPUT);
  

}

void loop() {
    
    
  // put your main code here, to run repeatedly:

val = digitalRead(BUTTON);

    if (val == HIGH && old_val == LOW) {
    
      // 注释2
      state = 1 - state;
    }
    old_val = val;  //  注释1

    if (state == 1) {
    
    
      digitalWrite(LED, HIGH);
    } else {
    
    
      digitalWrite(LED, LOW);
    }
  

}