LCD Keypad Shield

#include <LiquidCrystal.h>

/******************************************************* 这个程序用来测试LCD液晶显示模块和5个按键。 ********************************************************/

// 选择LCD上使用到的引脚
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// 定义各按键
int lcd_key     = 0;
int adc_key_in  = 0;

#define btnRIGHT 0
#define btnUP 1
#define btnDOWN 2
#define btnLEFT 3
#define btnSELECT 4
#define btnNONE 5

//读取按键值
int read_LCD_buttons()
{ 
   
 adc_key_in = analogRead(0);          // 从模拟口0读值 
 // 直接读到的5个按键值在以下值附近：0,144,329,504,741
 // 通过设定不同的阀值，就可以对应读到相应的按键
 if (adc_key_in > 1000) return btnNONE; 
 if (adc_key_in < 50)   return btnRIGHT;  
 if (adc_key_in < 250)  return btnUP; 
 if (adc_key_in < 450)  return btnDOWN; 
 if (adc_key_in < 650)  return btnLEFT; 
 if (adc_key_in < 850)  return btnSELECT;  

 // V1.0的版本使用以下的阀值：
/* if (adc_key_in < 50) return btnRIGHT; if (adc_key_in < 195) return btnUP; if (adc_key_in < 380) return btnDOWN; if (adc_key_in < 555) return btnLEFT; if (adc_key_in < 790) return btnSELECT; */

 return btnNONE; 
}

void setup()
{ 
   
 lcd.begin(16, 2);              // 开始
 lcd.setCursor(0,0);
 lcd.print("Push the buttons"); // 输出“Push the buttons”
}
 
void loop()
{ 
   
 lcd.setCursor(9,1);            // 光标定在第二行，空开9格
 lcd.print(millis()/1000);      // 输出等待时间


 lcd.setCursor(0,1);            // 光标移动到第二行开头
 lcd_key = read_LCD_buttons();  // 读取按键

 switch (lcd_key)               // 选择按键
 { 
   
   case btnRIGHT:
     { 
   
     lcd.print("RIGHT ");
     break;
     }
   case btnLEFT:
     { 
   
     lcd.print("LEFT ");
     break;
     }
   case btnUP:
     { 
   
     lcd.print("UP ");
     break;
     }
   case btnDOWN:
     { 
   
     lcd.print("DOWN ");
     break;
     }
   case btnSELECT:
     { 
   
     lcd.print("SELECT");
     break;
     }
     case btnNONE:
     { 
   
     lcd.print("NONE ");
     break;
     }
 }
}

样例代码
/******************************************************* Description: Reads an analog input on pin 1, prints the result to the LCD. This program takes the temperture sensor LM35 for example. Connection: Plug the LCD Keypad to the UNO(or other controllers) Temperture sensor: S(blue) -- A1() Note: A0 has been occupied. VCC(red) -- VCC GND(black) -- GND ********************************************************/

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);        // select the pins used on the LCD panel

unsigned long tepTimer ;    

void setup(){ 
    
    lcd.begin(16, 2);                       // start the library
}

void loop(){ 
    
    lcd.setCursor(0, 0);                   // set the LCD cursor position 
    int val;                               // variable to store the value coming from the analog pin 
    double data;                           // variable to store the temperature value coming from the conversion formula
    val=analogRead(1);                     // read the analog in value:
    data = (double) val * (5/10.24);       // temperature conversion formula
    
    if(millis() - tepTimer > 500){ 
            // output a temperature value per 500ms 
             tepTimer = millis();

             // print the results to the lcd
             lcd.print("T: ");               
             lcd.print(data);             
             lcd.print("C");              
     } 
}