Arduino键盘简单代码不起作用

Question

/* @file CustomKeypad.pde
|| @version 1.0
|| @author Alexander Brevig
|| @contact alexanderbrevig@gmail.com
||
|| @description
|| | Demonstrates changing the keypad size and key values.
|| #
*/

我不明白这个简单的代码，该代码经认证不起作用。 我收到消息：小键盘：41：错误：未在此范围内声明“ led_pin”，否则digitalWrite（led_pin，LOW）;

#include <Keypad.h>

int led_pin=13;
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
//define the cymbols on the buttons of the keypads
char hexaKeys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

//initialize an instance of class NewKeypad
Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); 

void setup(){
  pinMode(led_pin,OUTPUT);
  Serial.begin(9600);
}

void loop(){
  char customKey = customKeypad.getKey();

  if (customKey){
    digitalWrite(led_pin,HIGH);
    Serial.println(customKey);
    delay(100);
  }
   else digitalWrite(led_pin,LOW);
}

而且，如果我将另一个ledd_pin声明放入循环中，则会收到消息：在函数'void loop（）'中：Keyboard：35：error：在此范围内未声明'customKeypad'char char customKey = customKeypad.getKey（）;

这首歌很奇怪，因为Everythig必须在该非常简单的程序上工作。

Answer 1

我认为您应该在循环中检查'if语句的结构。

void loop(){
  char customKey = customKeypad.getKey();

  if (customKey){
    digitalWrite(led_pin,HIGH);
    Serial.println(customKey);
    delay(100);
  } else {
    digitalWrite(led_pin,LOW);
  }
}