RotaryEncoderLCD.ino

//example use of LCD4Bit_mod library

#include <LCD4Bit_mod.h> 
//create object to control an LCD.  
//number of lines in display=1
LCD4Bit_mod lcd = LCD4Bit_mod(2); 

//these pins can not be changed 2/3 are special pins
int encoderPin1 = 2;
int encoderPin2 = 3;
int encoderSwitchPin = 13; //push button switch

int encoderUpdated = 0;

//Key message
char msgs[5][15] = {"Right Key OK ", 
    				"Up Key OK    ", 
					"Down Key OK  ", 
					"Left Key OK  ", 
					"Select Key OK" };
int  adc_key_val[5] ={30, 150, 360, 535, 760 };
int NUM_KEYS = 5;
int adc_key_in;
int key=-1;
int oldkey=-1;

volatile int lastEncoded = 0;
volatile long encoderValue = 0;

long lastencoderValue = 0;

int lastMSB = 0;
int lastLSB = 0;


void setup() { 
      Serial.begin(19200);
      setupEncoder();
      
	lcd.init();
	//optionally, now set up our application-specific display settings, overriding whatever the lcd did in lcd.init()
	//lcd.commandWrite(0x0F);//cursor on, display on, blink on.  (nasty!)
	lcd.clear();
	lcd.printIn("KEYPAD testing... pressing");
    
	Serial.println("KEYPAD testing... pressing");
}

void setupEncoder() {
    pinMode(encoderPin1, INPUT); 
    pinMode(encoderPin2, INPUT);

    pinMode(encoderSwitchPin, INPUT);
      
    digitalWrite(encoderPin1, HIGH); //turn pullup resistor on
    digitalWrite(encoderPin2, HIGH); //turn pullup resistor on

    digitalWrite(encoderSwitchPin, HIGH); //turn pullup resistor on
      
    //call updateEncoder() when any high/low changed seen
    //on interrupt 0 (pin 2), or interrupt 1 (pin 3) 
    attachInterrupt(0, updateEncoder, CHANGE); 
    attachInterrupt(1, updateEncoder, CHANGE);
}

void loop() {

	adc_key_in = analogRead(0);    // read the value from the sensor  
	key = get_key(adc_key_in);		        // convert into key press
	
if (encoderUpdated > 0)
        {
          encoderUpdated = 0;
          
            char temp[16];
            dtostrf(encoderValue,8,8,temp);
            String tempAsString = String(temp);
            String s = "encoder: " + tempAsString + "      ";
            
            lcd.cursorTo(2, 0);  //line=2, x=0
            lcd.printIn(temp);
          
            Serial.println(s);
            
        } else if (key != oldkey)				    // if keypress is detected
	{
		delay(50);		// wait for debounce time
		adc_key_in = analogRead(0);    // read the value from the sensor  
		key = get_key(adc_key_in);		        // convert into key press
		if (key != oldkey)				
		{			
			oldkey = key;
			if (key >=0){
				lcd.cursorTo(2, 0);  //line=2, x=0
				lcd.printIn(msgs[key]);
				Serial.println(msgs[key]);
			}
		}
	} else if(!digitalRead(encoderSwitchPin)){
          //button is being pushed
          Serial.println("button pushed");
          
          lcd.cursorTo(2, 0);  //line=2, x=0
          lcd.printIn("button pushed");
        }

  delay(100); //just here to slow down the output, and show it will work  even during a delay
}

void updateEncoder(){
  int MSB = digitalRead(encoderPin1); //MSB = most significant bit
  int LSB = digitalRead(encoderPin2); //LSB = least significant bit

  int encoded = (MSB << 1) |LSB; //converting the 2 pin value to single number
  int sum  = (lastEncoded << 2) | encoded; //adding it to the previous encoded value

  if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue ++;
  if(sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue --;

  lastEncoded = encoded; //store this value for next time
  
  encoderUpdated = 1;
}

// Convert ADC value to key number
int get_key(unsigned int input)
{
	int k;
    
	for (k = 0; k < NUM_KEYS; k++)
	{
		if (input < adc_key_val[k])
		{
           
			return k;
		}
	}
    
	if (k >= NUM_KEYS)
		k = -1;     // No valid key pressed
    
	return k;
}