LCD 计数器

Mastertobe

一下是编程
[mw_shl_code=cpp,true]/* LiquidCrystal push button counter */
#include <LiquidCrystal.h>
LiquidCrystal lcd(12,11,5,4,3,2); //pins that lcd is attached to
const int buttonPin = 8; //the pin that pushbutton is attached to
const int ledPin = 13; //the pin that led is attached to
int buttonPushCounter = 0; //counter for the number of button presses
int buttonState = 0;  //current state of the button
int lastButtonState = 0; //previous state of the button
void setup(){
  pinMode(ledPin, OUTPUT); //initialize the button led pin as a out put
  lcd.begin(16,2); //set up the lcd's number of columns and rows
  lcd.setCursor(0,0); //set the column and row of the lcd print
  lcd.print("PBC:"); //print a message to lcd
}
void loop(){
  buttonState = digitalRead(buttonPin); //read the button input pin
  
  //compare the buttonState to its previous state
  if (buttonState != lastButtonState){
    //if the state has chaged, increment the counter
    if (buttonState ==HIGH){
      //if the current state is HIGH then the button went from off to on
    buttonPushCounter ++;
    lastButtonState = buttonState; //save the current state as the laststate
    lcd.setCursor (0,1); //set the column and row of the lcd print
    lcd.print (buttonPushCounter); //print the number of button presses
    digitalWrite (ledPin, HIGH); // if the led current state is HIGH then the led went from off to on
}
  else{
    lastButtonState = buttonState;  //save the current state as the laststate
    digitalWrite (ledPin, LOW);  // if the led current state is LOW then the led will be off
  }
}
}
[/mw_shl_code]


各位大神看看，有什么错误，为什么我有时候按键的时候数字会跳 两下

电网

八成是因为你的按钮机械杂波干扰，滤波即可。

硬件解决：按钮并联一个0.1u的小电容。
软件解决：在23行之后加一个delay(100)。

Mastertobe

电网 发表于 2013-2-12 21:30
八成是因为你的按钮机械杂波干扰，滤波即可。

硬件解决：按钮并联一个0.1u的小电容。

多谢啦，问题解决