i2c LCD display with rotary encoder 1

Sunday 2 April 2017

i2c LCD display with rotary encoder 1

My first test of trying a rotary encoder with a LCD display.

Many thanks to John Miller for his excellent video.

https://www.youtube.com/watch?v=vUjf8l35uy4

Project Source: https://github.com/jpsrmiller/rotary-encoder-i2c-lcd

I've had to adjust the code a bit along with the wiring of the encoder as I didn't have a ky-040 encoder

The KY-040 has a breakout board which adds a Vcc pin

The virgin encoder doesn't have this.

It has 5 pins:

1. CLK - Clock (Out B)

2. DT - data (Out A)

3. SW - switch (when we press the shaft, the switch connects to GND. Otherwise it is floating.)

4. GND

5. GND

You most often will find encoders without the breakout board.

They still have 5 pins.

Here there are two GNDs

There is no Vcc

The bare Rotary Encoder is connected to the following Arduino Uno pins
//      o CLK (out B) --> Pin 2
//      o DT (Out A) --> Pin 3
//      o SW --> Pin 4
//      o GND --> Pin 6 & GND on arduino

Here is my adapted code:

// ********************************************

// *************************************************************************************
// LCDRotaryTest16x2.ino - Test Program for Character LCD with I2C and KY-040 Rotary Encoder
//    Author:         John Miller
//    Revision:       1.0.1
//    Date:           5/25/2020
//    Project Source: https://github.com/jpsrmiller/rotary-encoder-i2c-lcd
//
// This Arduino program provides an example for using a KY-040 Rotary Encoder and
//   a 16x2 or 20x4 Character LCD with I2C interface
//
// The program may be freely copied, modified, and used for any Arduino projects
//
// The KY-040 Rotary Encoder is connected to the following Arduino Uno pins
//      o CLK --> Pin 2
//      o DT --> Pin 3
//      o SW --> Pin 4
//      o +   --> Pin 5
//      o GND --> Pin 6
//
// The LCD is connected to the following Arduino Uno pins
//      o GND --> GND
//      o VCC --> 5V
//      o SDA --> Pin A4 (SDA)
//      o SCL --> Pin A5 (SCL)
//
// The Rotary Encoder uses Arduino pins for the GND and +5V so that the remaining
//   5V and GND pins on the Arduino Uno can be used for other peripheral devices
// This works because the the Rotary Encoder draws less than the 40 mA
//   maximum current allowed on the Arduino Uno I/O pins
//
// *** External Libraries Required ***
// The following libraries must be downloaded and copied into the Arduino "libraries"
// folder in order for the program to compile:
//    o OneButton - https://github.com/mathertel/OneButton
//    o LiquidCrystal_I2C - https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library
//
// *********************************************************************************

#include <Arduino.h>
#include <Wire.h>
#include <OneButton.h>
#include <LiquidCrystal_I2C.h>

// Define the IO Pins Used
#define PIN_ROTARY_CLK    2   // Used for generating interrupts using CLK signal
#define PIN_ROTARY_DAT    3   // Used for reading DT signal
#define PIN_ROTARY_SW     4   // Used for the Rotary push button switch
#define PIN_ROTARY_5V     5   // Set to HIGH to be the 5V pin for the Rotary Encoder
#define PIN_ROTARY_GND    6   // Set to LOW to be the GND pin for the Rotary Encoder

// Most I2C LCD's have an I2C Address of either 0x27 or 0x3F
// If the LCD doesn't work with one address, try the other
//#define LCD_I2C_ADDRESS 0x27
//#define LCD_I2C_ADDRESS     0x3F

// Define the size of the LCD. Most LCD's are either 16x2 or 20x4
//#define LCD_ROW_COUNT       2    // Number of Rows
//#define LCD_COL_COUNT       16   // Number of Characters per Row

// OneButton class handles Debounce and detects button press
OneButton btnRot(PIN_ROTARY_SW, HIGH);      // Rotary Select button

LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
// LiquidCrystal_I2C lcd(LCD_I2C_ADDRESS, LCD_COL_COUNT, LCD_ROW_COUNT);

// Used for the Rotary Encoder interrupt routines PinA() and PinB()
volatile int rotaryCount = 0;

// Disables the Rotary Encoder interrupts while the LCD is being updated
byte rotaryDisabled;

volatile byte aFlag = 0; // lets us know when we're expecting a rising edge on pinA
             // to signal that the encoder has arrived at a detent
volatile byte bFlag = 0; // lets us know when we're expecting a rising edge on pinB
             // to signal that the encoder has arrived at a detent
             // (opposite direction to when aFlag is set)
volatile byte reading = 0; //somewhere to store the direct values we read from our interrupt
               // pins before checking to see if we have moved a whole detent

// ****************************************************************************
// PinA() - Called by the Interrupt pin when the Rotary Encoder Turned
//    Routine based on Simon Merrett - Improved Arduino Rotary Encoder Reading
//    https://www.instructables.com/id/Improved-Arduino-Rotary-Encoder-Reading/
// ****************************************************************************
void PinA() {

if (rotaryDisabled) return;

cli(); //stop interrupts happening before we read pin values
       // read all eight pin values then strip away all but pinA and pinB's values
reading = PIND & 0xC;

//check that both pins at detent (HIGH) and that we are expecting detent on this pin's rising edge
if (reading == B00001100 && aFlag) {
    rotaryRight();
    bFlag = 0; //reset flags for the next turn
    aFlag = 0; //reset flags for the next turn
}
//signal that we're expecting pinB to signal the transition to detent from free rotation
else if (reading == B00000100) bFlag = 1;
sei(); //restart interrupts
}

// ****************************************************************************
// PinB() - Called by the Interrupt pin when the Rotary Encoder Turned
//    Routine based on Simon Merrett - Improved Arduino Rotary Encoder Reading
//    https://www.instructables.com/id/Improved-Arduino-Rotary-Encoder-Reading/
// ****************************************************************************
void PinB() {

if (rotaryDisabled) return;

cli(); //stop interrupts happening before we read pin values
       //read all eight pin values then strip away all but pinA and pinB's values
reading = PIND & 0xC;
//check that both pins at detent (HIGH) and that we are expecting detent on this pin's rising edge
if (reading == B00001100 && bFlag) {
    rotaryLeft();
    bFlag = 0; //reset flags for the next turn
    aFlag = 0; //reset flags for the next turn
}
//signal that we're expecting pinA to signal the transition to detent from free rotation
else if (reading == B00001000) aFlag = 1;
sei(); //restart interrupts
}

// ****************************************************************************
// rotaryRight() - Rotary Encoder is turned 1 detent to the Right (clockwise)
//              Insert your own code here.
// ****************************************************************************
void rotaryRight()
{
rotaryCount++;
}

// **********************************************************************************
// rotaryLeft() - Rotary Encoder is turned 1 detent to the Left (counter-clockwise)
//                Insert your own code here.
// **********************************************************************************
void rotaryLeft()
{
rotaryCount--;
}

// ****************************************************************************
// rotaryClick() - Rotary Encoder Select Switch is pressed
//                 Insert your own code here.
// ****************************************************************************
void rotaryClick()
{
rotaryCount += 100;
}

// ****************************************************************************
// rotaryLongPress() - Rotary Encoder Select Switch is Held Down (Long Press)
//                     Insert your own code here.
// ****************************************************************************
void rotaryLongPress()
{
rotaryCount = 0;
}

// ****************************************************************************
// initializeRotaryEncoder() - Initialize the pins and interrupt functions
//                             for the Rotary Encoder
// ****************************************************************************
void initializeRotaryEncoder()
{
// Set the Directions of the I/O Pins
pinMode(PIN_ROTARY_CLK, INPUT_PULLUP);
pinMode(PIN_ROTARY_DAT, INPUT_PULLUP);
pinMode(PIN_ROTARY_SW, INPUT_PULLUP);
pinMode(PIN_ROTARY_GND, OUTPUT);
pinMode(PIN_ROTARY_5V, OUTPUT);

// Set the 5V and GND pins for the Rotary Encoder
digitalWrite(PIN_ROTARY_GND, LOW);
digitalWrite(PIN_ROTARY_5V, HIGH);

// set an interrupt on PinA and PinB, looking for a rising edge signal and
// executing the "PinA" and "PinB" Interrupt Service Routines
attachInterrupt(0, PinA, RISING);
attachInterrupt(1, PinB, RISING);

// Define the functions for Rotary Encoder Click and Long Press
btnRot.attachClick(&rotaryClick);
btnRot.attachLongPressStart(&rotaryLongPress);
btnRot.setPressTicks(2000);

rotaryDisabled = 0;
}

// ****************************************************************************
// initializeLcd() - Initialize the LCD
// ****************************************************************************
void initializeLcd()
{
lcd.begin(16,2);
lcd.backlight();
lcd.clear();
lcd.setCursor(0, 0);
lcd.print(F("Test LCD & Rotry"));
}

// ****************************************************************************
// updateLcd() - Update the LCD with current Rotary Encoder detent count
// ****************************************************************************
void updateLcd()
{
rotaryDisabled = 1;
lcd.setCursor(0, 1);
lcd.print(F("Count = "));
lcd.print(rotaryCount);
lcd.print(F("       "));
rotaryDisabled = 0;
}

// ****************************************************************************
// setup() - Initialization Function
// ****************************************************************************
void setup()
{
initializeRotaryEncoder();
initializeLcd();
}

// ****************************************************************************
// loop() - Main Program Loop Function
// ****************************************************************************
void loop()
{
updateLcd();
btnRot.tick();
delay(50);
}

// ***********************************