Clock – Tutorials

In this tutorial you will make a simple clock. Doing this you will learn how to replace a tangled set of if's with state machine. If you don't know how state machine works, please read first my Control actions with state machine tutorial.

Table of contents:

Iteration 1
Iteration 2
- General idea of states and actions flow
- An inital code taking control on the small subset of states and actions
Iteration 3
Iteration 4

Iteration 1

In this iteration you:

make initial cicruit consisting of microcontroller, LCD with I2C adapter and one tact switch (button);
measure the passage of time using millis() function;
reset time after pressing the button.

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

#define PIN_RESET 7
#define UPDATE_INTERVAL 1000

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock
unsigned long vcCurrentTime;
unsigned long vcDeltaTime;
unsigned long vcLastUpdate;
// END: For my virtual clock

char hours, minutes, seconds;
unsigned long deltaTime;
unsigned long currentTime; // Current time in milli seconds
unsigned long ct; // Current time in seconds
unsigned long lastUpdate;
char buff[64];

void setup() {
  vcLastUpdate = 0;
  lastUpdate = 0;
  Serial.begin(9600);
  pinMode(PIN_RESET, INPUT);

  lcd.init();
  lcd.backlight();
}

void getTime() {
  ct = currentTime/1000;
  hours = ct / 3600;
  minutes = (ct - hours * 3600) / 60;
  seconds = ct - hours * 3600 - minutes * 60;

  if (hours == 24) {
    hours = 0;
  }
}

// Create my virtual clock to control it independently
// of the actual passage of time.
unsigned long updateVirtualClock() {
  vcCurrentTime = millis();
  if (vcCurrentTime >= vcLastUpdate) {
    vcDeltaTime = vcCurrentTime - vcLastUpdate;
    currentTime += vcDeltaTime;
  } else {
    vcDeltaTime = vcLastUpdate - vcCurrentTime;
    currentTime = vcDeltaTime;
  }
  vcLastUpdate = vcCurrentTime;
}

void updateDisplay() {
  deltaTime = currentTime - lastUpdate;
  
  // Non-blocking time print once every second
  if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {
    lastUpdate = currentTime;
    getTime();
    sprintf(buff, "%02d:%02d:%02d", hours, minutes, seconds);
    Serial.println(buff);

    lcd.setCursor(0,0);
    lcd.print(buff);
  }
}

void loop() {
  updateVirtualClock();
  
  updateDisplay();

  if(digitalRead(PIN_RESET) == HIGH){
    delay(20);

    currentTime = 0;
  }
}

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

#define PIN_RESET 7

#define UPDATE_INTERVAL 1000

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock

unsigned long vcCurrentTime;

unsigned long vcDeltaTime;

unsigned long vcLastUpdate;

// END: For my virtual clock

char hours, minutes, seconds;

unsigned long deltaTime;

unsigned long currentTime; // Current time in milli seconds

unsigned long ct; // Current time in seconds

unsigned long lastUpdate;

char buff[64];

void setup() {

vcLastUpdate = 0;

lastUpdate = 0;

Serial.begin(9600);

pinMode(PIN_RESET, INPUT);

lcd.init();

lcd.backlight();

}

void getTime() {

ct = currentTime/1000;

hours = ct / 3600;

minutes = (ct - hours * 3600) / 60;

seconds = ct - hours * 3600 - minutes * 60;

if (hours == 24) {

hours = 0;

}

// Create my virtual clock to control it independently

// of the actual passage of time.

unsigned long updateVirtualClock() {

vcCurrentTime = millis();

if (vcCurrentTime >= vcLastUpdate) {

vcDeltaTime = vcCurrentTime - vcLastUpdate;

currentTime += vcDeltaTime;

} else {

vcDeltaTime = vcLastUpdate - vcCurrentTime;

currentTime = vcDeltaTime;

}

vcLastUpdate = vcCurrentTime;

}

void updateDisplay() {

deltaTime = currentTime - lastUpdate;

// Non-blocking time print once every second

if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {

lastUpdate = currentTime;

getTime();

sprintf(buff, "%02d:%02d:%02d", hours, minutes, seconds);

Serial.println(buff);

lcd.setCursor(0,0);

lcd.print(buff);

}

void loop() {

updateVirtualClock();

updateDisplay();

if(digitalRead(PIN_RESET) == HIGH){

delay(20);

currentTime = 0;

}

Iteration 2

In this iteration you:

add all buttons required to control your clock;
make a diagram showing actions and how they reflect state changes;
implement initial code for small subset of actions and states.

General idea of states and actions flow

An inital code taking control on the small subset of states and actions

Below you can find inital code taking control on the small subset of states and actions:

This should give you an overwiew how you can continue this approach to make fully functional clock. Just after the code you will find an animation how it works.

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

#define PIN_MENU 2
#define PIN_ENTER 3
#define PIN_NEXT 4
#define PIN_PREV 5

#define UPDATE_INTERVAL 1000

#define STATE_UNDEFINED 0
#define STATE_WAIT 1
#define STATE_SET_TIME 2
#define STATE_SET_ALARM 3
#define STATE_ALARM_ON_OFF 4

#define ACTION_NONE 0
#define ACTION_MENU 1
#define ACTION_ENTER 2
#define ACTION_NEXT 3
#define ACTION_PREV 4

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock
unsigned long vcCurrentTime;
unsigned long vcDeltaTime;
unsigned long vcLastUpdate;
// END: For my virtual clock

char hours, minutes, seconds;
unsigned long deltaTime;
unsigned long currentTime; // Current time in milli seconds
unsigned long ct; // Current time in seconds
unsigned long lastUpdate;
char buff[64];

int currentState = STATE_WAIT;
int lastState;
int action = ACTION_NONE;

void setup() {
  vcLastUpdate = 0;
  lastUpdate = 0;
  Serial.begin(9600);
  pinMode(PIN_MENU, INPUT);
  pinMode(PIN_ENTER, INPUT);
  pinMode(PIN_NEXT, INPUT);
  pinMode(PIN_PREV, INPUT);
  
  lcd.init();
  lcd.backlight();
}

void getTime() {
  ct = currentTime/1000;
  hours = ct / 3600;
  minutes = (ct - hours * 3600) / 60;
  seconds = ct - hours * 3600 - minutes * 60;

  if (hours == 24) {
    hours = 0;
  }
}

// Create my virtual clock to control it independently
// of the actual passage of time.
unsigned long updateVirtualClock() {
  vcCurrentTime = millis();
  if (vcCurrentTime >= vcLastUpdate) {
    vcDeltaTime = vcCurrentTime - vcLastUpdate;
    currentTime += vcDeltaTime;
  } else {
    vcDeltaTime = vcLastUpdate - vcCurrentTime;
    currentTime = vcDeltaTime;
  }
  vcLastUpdate = vcCurrentTime;
}

void displayCurrentTime() {
  deltaTime = currentTime - lastUpdate;
  
  // Non-blocking time print once every second
  if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {
    lastUpdate = currentTime;
    getTime();
    sprintf(buff, "%02d:%02d:%02d        ", hours, minutes, seconds);
    //Serial.println(buff);

    lcd.setCursor(0,0);
    lcd.print(buff);
  }
}

void menuLevel1(int option) {
    if (option == 1) {
      lcd.clear();
      lcd.print("1. Set time");
    } else if (option == 2) {
      lcd.clear();
      lcd.print("2. Set alarm");
    } else if (option == 3) {
      lcd.clear();
      lcd.print("3. Alarm on/off");
    }
    
}

void makeAnAction(int newAction) {
  action = newAction;
}

void changeState(int newState) {
  currentState = newState;
}


void testButtons() {
  if(digitalRead(PIN_MENU) == HIGH){
    delay(20);
    while(digitalRead(PIN_MENU) == HIGH);
    delay(20);

    makeAnAction(ACTION_MENU);
  } else if(digitalRead(PIN_ENTER) == HIGH){
    delay(20);
    while(digitalRead(PIN_ENTER) == HIGH);
    delay(20);

    makeAnAction(ACTION_ENTER);
  } else if(digitalRead(PIN_NEXT) == HIGH){
    delay(20);
    while(digitalRead(PIN_NEXT) == HIGH);
    delay(20);

    makeAnAction(ACTION_NEXT);
  } else if(digitalRead(PIN_PREV) == HIGH){
    delay(20);
    while(digitalRead(PIN_PREV) == HIGH);
    delay(20);

    makeAnAction(ACTION_PREV);
  }
}


void loop() {
  updateVirtualClock();
  
  testButtons();

  if (currentState == STATE_WAIT) {
    displayCurrentTime();

    if (action == ACTION_MENU) {
      changeState(STATE_SET_TIME);
    }
    makeAnAction(ACTION_NONE);
    lastState = STATE_WAIT;
  } else if (currentState == STATE_SET_TIME) {
    if (lastState != currentState) {
      menuLevel1(1);
    }

    if (action == ACTION_MENU) {
      changeState(STATE_WAIT);
    } else if (action == ACTION_NEXT) {
      changeState(STATE_SET_ALARM);
    } else if (action == ACTION_PREV) {
      changeState(STATE_ALARM_ON_OFF);
    }
    makeAnAction(ACTION_NONE);
    lastState = STATE_SET_TIME;
  } else if (currentState == STATE_SET_ALARM) {
    if (lastState != currentState) {
      menuLevel1(2);
    }

    if (action == ACTION_MENU) {
      changeState(STATE_WAIT);
    } else if (action == ACTION_NEXT) {
      changeState(STATE_ALARM_ON_OFF);
    } else if (action == ACTION_PREV) {
      changeState(STATE_SET_TIME);
    }
    makeAnAction(ACTION_NONE);
    lastState = STATE_SET_ALARM;
  } else if (currentState == STATE_ALARM_ON_OFF) {
    if (lastState != currentState) {
      menuLevel1(3);
    }

    if (action == ACTION_MENU) {
      changeState(STATE_WAIT);
    } else if (action == ACTION_NEXT) {
      changeState(STATE_SET_TIME);
    } else if (action == ACTION_PREV) {
      changeState(STATE_SET_ALARM);
    }
    makeAnAction(ACTION_NONE);
    lastState = STATE_ALARM_ON_OFF;
  }
}

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#include <Wire.h>

#include <LiquidCrystal_I2C.h>

#define PIN_MENU 2

#define PIN_ENTER 3

#define PIN_NEXT 4

#define PIN_PREV 5

#define UPDATE_INTERVAL 1000

#define STATE_UNDEFINED 0

#define STATE_WAIT 1

#define STATE_SET_TIME 2

#define STATE_SET_ALARM 3

#define STATE_ALARM_ON_OFF 4

#define ACTION_NONE 0

#define ACTION_MENU 1

#define ACTION_ENTER 2

#define ACTION_NEXT 3

#define ACTION_PREV 4

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock

unsigned long vcCurrentTime;

unsigned long vcDeltaTime;

unsigned long vcLastUpdate;

// END: For my virtual clock

char hours, minutes, seconds;

unsigned long deltaTime;

unsigned long currentTime; // Current time in milli seconds

unsigned long ct; // Current time in seconds

unsigned long lastUpdate;

char buff[64];

int currentState = STATE_WAIT;

int lastState;

int action = ACTION_NONE;

void setup() {

vcLastUpdate = 0;

lastUpdate = 0;

Serial.begin(9600);

pinMode(PIN_MENU, INPUT);

pinMode(PIN_ENTER, INPUT);

pinMode(PIN_NEXT, INPUT);

pinMode(PIN_PREV, INPUT);

lcd.init();

lcd.backlight();

}

void getTime() {

ct = currentTime/1000;

hours = ct / 3600;

minutes = (ct - hours * 3600) / 60;

seconds = ct - hours * 3600 - minutes * 60;

if (hours == 24) {

hours = 0;

}

// Create my virtual clock to control it independently

// of the actual passage of time.

unsigned long updateVirtualClock() {

vcCurrentTime = millis();

if (vcCurrentTime >= vcLastUpdate) {

vcDeltaTime = vcCurrentTime - vcLastUpdate;

currentTime += vcDeltaTime;

} else {

vcDeltaTime = vcLastUpdate - vcCurrentTime;

currentTime = vcDeltaTime;

}

vcLastUpdate = vcCurrentTime;

}

void displayCurrentTime() {

deltaTime = currentTime - lastUpdate;

// Non-blocking time print once every second

if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {

lastUpdate = currentTime;

getTime();

sprintf(buff, "%02d:%02d:%02d ", hours, minutes, seconds);

//Serial.println(buff);

lcd.setCursor(0,0);

lcd.print(buff);

}

void menuLevel1(int option) {

if (option == 1) {

lcd.clear();

lcd.print("1. Set time");

} else if (option == 2) {

lcd.clear();

lcd.print("2. Set alarm");

} else if (option == 3) {

lcd.clear();

lcd.print("3. Alarm on/off");

}

void makeAnAction(int newAction) {

action = newAction;

}

void changeState(int newState) {

currentState = newState;

}

void testButtons() {

if(digitalRead(PIN_MENU) == HIGH){

delay(20);

while(digitalRead(PIN_MENU) == HIGH);

delay(20);

makeAnAction(ACTION_MENU);

} else if(digitalRead(PIN_ENTER) == HIGH){

delay(20);

while(digitalRead(PIN_ENTER) == HIGH);

delay(20);

makeAnAction(ACTION_ENTER);

} else if(digitalRead(PIN_NEXT) == HIGH){

delay(20);

while(digitalRead(PIN_NEXT) == HIGH);

delay(20);

makeAnAction(ACTION_NEXT);

} else if(digitalRead(PIN_PREV) == HIGH){

delay(20);

while(digitalRead(PIN_PREV) == HIGH);

delay(20);

makeAnAction(ACTION_PREV);

}

void loop() {

updateVirtualClock();

testButtons();

if (currentState == STATE_WAIT) {

displayCurrentTime();

if (action == ACTION_MENU) {

changeState(STATE_SET_TIME);

}

makeAnAction(ACTION_NONE);

lastState = STATE_WAIT;

} else if (currentState == STATE_SET_TIME) {

if (lastState != currentState) {

menuLevel1(1);

}

if (action == ACTION_MENU) {

changeState(STATE_WAIT);

} else if (action == ACTION_NEXT) {

changeState(STATE_SET_ALARM);

} else if (action == ACTION_PREV) {

changeState(STATE_ALARM_ON_OFF);

}

makeAnAction(ACTION_NONE);

lastState = STATE_SET_TIME;

} else if (currentState == STATE_SET_ALARM) {

if (lastState != currentState) {

menuLevel1(2);

}

if (action == ACTION_MENU) {

changeState(STATE_WAIT);

} else if (action == ACTION_NEXT) {

changeState(STATE_ALARM_ON_OFF);

} else if (action == ACTION_PREV) {

changeState(STATE_SET_TIME);

}

makeAnAction(ACTION_NONE);

lastState = STATE_SET_ALARM;

} else if (currentState == STATE_ALARM_ON_OFF) {

if (lastState != currentState) {

menuLevel1(3);

}

if (action == ACTION_MENU) {

changeState(STATE_WAIT);

} else if (action == ACTION_NEXT) {

changeState(STATE_SET_TIME);

} else if (action == ACTION_PREV) {

changeState(STATE_SET_ALARM);

}

makeAnAction(ACTION_NONE);

lastState = STATE_ALARM_ON_OFF;

}

An inital code taking control on the small subset of states and actions in action

Iteration 3

In this iteration you:

turn a set of ifs into state machine which simplifies code development.

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

#define PIN_MENU 2
#define PIN_ENTER 3
#define PIN_NEXT 4
#define PIN_PREV 5

#define UPDATE_INTERVAL 1000

#define STATE_UNDEFINED 0
#define STATE_WAIT 1
#define STATE_SET_TIME 2
#define STATE_SET_ALARM 3
#define STATE_ALARM_ON_OFF 4

#define ACTION_NONE 0
#define ACTION_TICK 1
#define ACTION_MENU 2
#define ACTION_ENTER 3
#define ACTION_NEXT 4
#define ACTION_PREV 5

#define INDEX_STATE_CURRENT 0
#define INDEX_ACTION 1
#define INDEX_STATE_NEW 2

#define NUMBER_OF_ROUTES 11
 
// Warning!!!
// Remember to update NUMBER_OF_ROUTES when changing routing table
byte   routes[][3] = 
                   {{STATE_WAIT, ACTION_TICK, STATE_WAIT},
                   {STATE_WAIT, ACTION_MENU, STATE_SET_TIME},
                   
                   {STATE_SET_TIME, ACTION_NEXT, STATE_SET_ALARM},
                   {STATE_SET_TIME, ACTION_PREV, STATE_ALARM_ON_OFF},
                   {STATE_SET_TIME, ACTION_MENU, STATE_WAIT},
                   
                   {STATE_SET_ALARM, ACTION_NEXT, STATE_ALARM_ON_OFF},
                   {STATE_SET_ALARM, ACTION_PREV, STATE_SET_TIME},
                   {STATE_SET_ALARM, ACTION_MENU, STATE_WAIT},
                   
                   {STATE_ALARM_ON_OFF, ACTION_NEXT, STATE_SET_TIME},
                   {STATE_ALARM_ON_OFF, ACTION_PREV, STATE_SET_ALARM},
                   {STATE_ALARM_ON_OFF, ACTION_MENU, STATE_WAIT}
                   };

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock
unsigned long vcCurrentTime;
unsigned long vcDeltaTime;
unsigned long vcLastUpdate;
// END: For my virtual clock

char hours, minutes, seconds;
unsigned long deltaTime;
unsigned long currentTime; // Current time in milli seconds
unsigned long ct; // Current time in seconds
unsigned long lastUpdate;
char buff[64];

int currentState = STATE_WAIT;
int lastState;
int action = ACTION_TICK;
int lastAction;

void setup() {
  vcLastUpdate = 0;
  lastUpdate = 0;
  Serial.begin(9600);
  pinMode(PIN_MENU, INPUT);
  pinMode(PIN_ENTER, INPUT);
  pinMode(PIN_NEXT, INPUT);
  pinMode(PIN_PREV, INPUT);

  lcd.init();
  lcd.backlight();
}

void getTime() {
  ct = currentTime/1000;
  hours = ct / 3600;
  minutes = (ct - hours * 3600) / 60;
  seconds = ct - hours * 3600 - minutes * 60;

  if (hours == 24) {
    hours = 0;
  }
}

// Create my virtual clock to control it independently
// of the actual passage of time.
unsigned long updateVirtualClock() {
  vcCurrentTime = millis();
  if (vcCurrentTime >= vcLastUpdate) {
    vcDeltaTime = vcCurrentTime - vcLastUpdate;
    currentTime += vcDeltaTime;
  } else {
    vcDeltaTime = vcLastUpdate - vcCurrentTime;
    currentTime = vcDeltaTime;
  }
  vcLastUpdate = vcCurrentTime;
}

void displayCurrentTime() {
  deltaTime = currentTime - lastUpdate;
  
  // Non-blocking time print once every second
  if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {
    lastUpdate = currentTime;
    getTime();
    sprintf(buff, "%02d:%02d:%02d        ", hours, minutes, seconds);
    //Serial.println(buff);

    lcd.setCursor(0,0);
    lcd.print(buff);
  }
}

void menuLevel1(int option) {
    if (option == 1) {
      lcd.clear();
      lcd.print("1. Set time");
    } else if (option == 2) {
      lcd.clear();
      lcd.print("2. Set alarm");
    } else if (option == 3) {
      lcd.clear();
      lcd.print("3. Alarm on/off");
    }
    
}

void makeAnAction(int newAction) {
  action = newAction;
}

void changeState(int newState) {
  currentState = newState;
}

void testButtons() {
  if(digitalRead(PIN_MENU) == HIGH){
    delay(20);
    while(digitalRead(PIN_MENU) == HIGH);
    delay(20);

    makeAnAction(ACTION_MENU);
  } else if(digitalRead(PIN_ENTER) == HIGH){
    delay(20);
    while(digitalRead(PIN_ENTER) == HIGH);
    delay(20);

    makeAnAction(ACTION_ENTER);
  } else if(digitalRead(PIN_NEXT) == HIGH){
    delay(20);
    while(digitalRead(PIN_NEXT) == HIGH);
    delay(20);

    makeAnAction(ACTION_NEXT);
  } else if(digitalRead(PIN_PREV) == HIGH){
    delay(20);
    while(digitalRead(PIN_PREV) == HIGH);
    delay(20);

    makeAnAction(ACTION_PREV);
  }
}

void loop() {
  updateVirtualClock();
  
  testButtons();
  
  stateMachine();
}

void stateWait() {
  displayCurrentTime();
  makeAnAction(ACTION_TICK);
}

void stateSetTime() {
  menuLevel1(1);
}

void stateSetAlarm() {
  menuLevel1(2);
}

void stateAlarmOnOff() {
  menuLevel1(3);
}

void executeStateAction(){
  switch(currentState)
  {
    case STATE_WAIT:
      stateWait();
      break;
    case STATE_SET_TIME:
      stateSetTime();
      break;
    case STATE_SET_ALARM:
      stateSetAlarm();
      break;
    case STATE_ALARM_ON_OFF:
      stateAlarmOnOff();
      break;
  }
}

void stateMachine(){
  byte i;

  //while(true) {
    if(action != ACTION_NONE){
      lastAction = action;
      makeAnAction(ACTION_NONE);
      for(i=0; i<NUMBER_OF_ROUTES; ++i){
        if(routes[i][INDEX_STATE_CURRENT] == currentState &&
          routes[i][INDEX_ACTION] == lastAction){
          changeState(routes[i][INDEX_STATE_NEW]);
          break;
        }
      }
      executeStateAction();
      lastState = currentState;
    }
  //}
}

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#include <Wire.h>

#include <LiquidCrystal_I2C.h>

#define PIN_MENU 2

#define PIN_ENTER 3

#define PIN_NEXT 4

#define PIN_PREV 5

#define UPDATE_INTERVAL 1000

#define STATE_UNDEFINED 0

#define STATE_WAIT 1

#define STATE_SET_TIME 2

#define STATE_SET_ALARM 3

#define STATE_ALARM_ON_OFF 4

#define ACTION_NONE 0

#define ACTION_TICK 1

#define ACTION_MENU 2

#define ACTION_ENTER 3

#define ACTION_NEXT 4

#define ACTION_PREV 5

#define INDEX_STATE_CURRENT 0

#define INDEX_ACTION 1

#define INDEX_STATE_NEW 2

#define NUMBER_OF_ROUTES 11

// Warning!!!

// Remember to update NUMBER_OF_ROUTES when changing routing table

byte routes[][3] =

{{STATE_WAIT, ACTION_TICK, STATE_WAIT},

{STATE_WAIT, ACTION_MENU, STATE_SET_TIME},

{STATE_SET_TIME, ACTION_NEXT, STATE_SET_ALARM},

{STATE_SET_TIME, ACTION_PREV, STATE_ALARM_ON_OFF},

{STATE_SET_TIME, ACTION_MENU, STATE_WAIT},

{STATE_SET_ALARM, ACTION_NEXT, STATE_ALARM_ON_OFF},

{STATE_SET_ALARM, ACTION_PREV, STATE_SET_TIME},

{STATE_SET_ALARM, ACTION_MENU, STATE_WAIT},

{STATE_ALARM_ON_OFF, ACTION_NEXT, STATE_SET_TIME},

{STATE_ALARM_ON_OFF, ACTION_PREV, STATE_SET_ALARM},

{STATE_ALARM_ON_OFF, ACTION_MENU, STATE_WAIT}

};

LiquidCrystal_I2C lcd(0x27,16,2);

// BEGIN: For my virtual clock

unsigned long vcCurrentTime;

unsigned long vcDeltaTime;

unsigned long vcLastUpdate;

// END: For my virtual clock

char hours, minutes, seconds;

unsigned long deltaTime;

unsigned long currentTime; // Current time in milli seconds

unsigned long ct; // Current time in seconds

unsigned long lastUpdate;

char buff[64];

int currentState = STATE_WAIT;

int lastState;

int action = ACTION_TICK;

int lastAction;

void setup() {

vcLastUpdate = 0;

lastUpdate = 0;

Serial.begin(9600);

pinMode(PIN_MENU, INPUT);

pinMode(PIN_ENTER, INPUT);

pinMode(PIN_NEXT, INPUT);

pinMode(PIN_PREV, INPUT);

lcd.init();

lcd.backlight();

}

void getTime() {

ct = currentTime/1000;

hours = ct / 3600;

minutes = (ct - hours * 3600) / 60;

seconds = ct - hours * 3600 - minutes * 60;

if (hours == 24) {

hours = 0;

}

// Create my virtual clock to control it independently

// of the actual passage of time.

unsigned long updateVirtualClock() {

vcCurrentTime = millis();

if (vcCurrentTime >= vcLastUpdate) {

vcDeltaTime = vcCurrentTime - vcLastUpdate;

currentTime += vcDeltaTime;

} else {

vcDeltaTime = vcLastUpdate - vcCurrentTime;

currentTime = vcDeltaTime;

}

vcLastUpdate = vcCurrentTime;

}

void displayCurrentTime() {

deltaTime = currentTime - lastUpdate;

// Non-blocking time print once every second

if ( deltaTime > UPDATE_INTERVAL || deltaTime < 0) {

lastUpdate = currentTime;

getTime();

sprintf(buff, "%02d:%02d:%02d ", hours, minutes, seconds);

//Serial.println(buff);

lcd.setCursor(0,0);

lcd.print(buff);

}

void menuLevel1(int option) {

if (option == 1) {

lcd.clear();

lcd.print("1. Set time");

} else if (option == 2) {

lcd.clear();

lcd.print("2. Set alarm");

} else if (option == 3) {

lcd.clear();

lcd.print("3. Alarm on/off");

}

void makeAnAction(int newAction) {

action = newAction;

}

void changeState(int newState) {

currentState = newState;

}

void testButtons() {

if(digitalRead(PIN_MENU) == HIGH){

delay(20);

while(digitalRead(PIN_MENU) == HIGH);

delay(20);

makeAnAction(ACTION_MENU);

} else if(digitalRead(PIN_ENTER) == HIGH){

delay(20);

while(digitalRead(PIN_ENTER) == HIGH);

delay(20);

makeAnAction(ACTION_ENTER);

} else if(digitalRead(PIN_NEXT) == HIGH){

delay(20);

while(digitalRead(PIN_NEXT) == HIGH);

delay(20);

makeAnAction(ACTION_NEXT);

} else if(digitalRead(PIN_PREV) == HIGH){

delay(20);

while(digitalRead(PIN_PREV) == HIGH);

delay(20);

makeAnAction(ACTION_PREV);

}

void loop() {

updateVirtualClock();

testButtons();

stateMachine();

}

void stateWait() {

displayCurrentTime();

makeAnAction(ACTION_TICK);

}

void stateSetTime() {

menuLevel1(1);

}

void stateSetAlarm() {

menuLevel1(2);

}

void stateAlarmOnOff() {

menuLevel1(3);

}

void executeStateAction(){

switch(currentState)

{

case STATE_WAIT:

stateWait();

break;

case STATE_SET_TIME:

stateSetTime();

break;

case STATE_SET_ALARM:

stateSetAlarm();

break;

case STATE_ALARM_ON_OFF:

stateAlarmOnOff();

break;

}

void stateMachine(){

byte i;

//while(true) {

if(action != ACTION_NONE){

lastAction = action;

makeAnAction(ACTION_NONE);

for(i=0; i<NUMBER_OF_ROUTES; ++i){

if(routes[i][INDEX_STATE_CURRENT] == currentState &&

routes[i][INDEX_ACTION] == lastAction){

changeState(routes[i][INDEX_STATE_NEW]);

break;

}

executeStateAction();

lastState = currentState;

}

//}

}

Iteration 4

In this iteration you:

add LED to signal alarm activation;
implement all required functionality according to description from iteration 2.

Code from this iteration is much longer than from previous. It's not more complicated but is longer simply because it implements all functionality. I also added to the circuit LED and buzzer. Because it's long I divided it into parts:

This code works - see the video (approx. 128MiB).