Arduino thermostat on 7-segment LED display

   I designed a thermostat with few components using an Arduino board.

   I use LM35DZ for temperture sensor, KW4-563ASA display (4 digit 7-segment with common anode), RGB led, 3 button (push button) for select and change the value for desired temperature and for hysteresis.

   I designed this schematic:

who is used also for an thermostat with 2 thesholds (must change the sketch).

   If measured temperature is less than desired temperture, blue led is on:

and if is to much, red led is on:

   If I push the MENU buton, display is change in:

(in right side, is "c" instead "C"). 

   If I push "-" button, temperature value decrease with 0.1 degree Celsius for each push, if I push "+" button, temperature increase with 0,1 degree Celsius for each push.

   After that, if I push again MENU button, I will see:

and I can change the value with 0.1 degree, like at desired temperature.

   Values for desired temperature and hysteresis are write and stored in internal EEPROM memory of microcontroler (any Arduno board has an microcontroller on it.)

   For easy understund this, I made a movie named Arduino thermostat

   Skech for this thermostat is put on https://github.com/tehniq3/thermostat !!!

PS:  Fist time when upload the sketch, must write default value for desired temprature and hysteresis:

after that, must comment the 3 lines:

   Actual sketch work with Arduino Uno board and you can see:

but for work with Arduino Mega board you must comment first line and uncomment second line:

PS2: If you want to connect a relay for control a heater system, subroutine leduri() must be changed in:

void leduri() {
 digitalWrite(CALD, LOW);
 digitalWrite(RECE, LOW);

if ( t0*10 < tset ) 
{  digitalWrite(RECE, HIGH);
   digitalWrite(CALD, LOW);
   pornire = 1;
}
if ( t0*10 > tset + dt ) 
{  digitalWrite(CALD, HIGH);
   digitalWrite(RECE, LOW);
   pornire = 0;
}

if (( t0*10 <= tset+dt ) && ( t0*10 >= tset )) {
if (pornire == 1)
{  digitalWrite(CALD, LOW);
   digitalWrite(RECE, HIGH);
}
if (pornire == 0)
{  digitalWrite(CALD, LOW);
   digitalWrite(RECE, LOW);
}
}
}

and at begin of sketch must define int pornire; and in setup must put pornire = 0; !!
   You can download changed sketch from https://github.com/tehniq3.
   In movie namend Arduino thermostat (2) you can see the changed style, like usual thermostat for a heater:

Manual adjust for RTC clock with Arduino and 7-segment LED display

   For a good clock must use a RTC (real-time clock) like DS1307. For Arduino enthusiasts and hobbylist exists some RTC module with DS1307, but you can made yourself a good RTC module like me.

   Original schematic is from DS1307 datasheet, but I redesigned schematic using freeversion of Eagle PCB Software:

   Note: Battery is CR2032, like in schematic... in boards is a little error

   A full schematic for RTC clock with Arduino is:

   Compared to other schematics that can adjust time (reset clock at 0:00, adjust hours and minutes). Original schematic, design and sketch is from article Using Arduino with a DS1307 Real Time Clock by Lewis Loflin.

   If you want to change time, must push and hold S3 (adjust) switch and display is change on 0:00, then push S1 (hour) or S2 (minute) repeatedly until time is ok, after this realise S3, and time is put in RTC.

   I use a multiplexed 4-digit 7-segment display with common anode same in article named Arduino UNO running 4-digit 7-segment display from http://www.hobbytronics.co.uk/. Is a unusual schematic, but works fine; a usual schematic use resistors for current limit.

   My sketch is:

/*
 4 digit 7 segment display: http://www.sparkfun.com/products/9483
 Datasheet: http://www.sparkfun.com/datasheets/Components/LED/7-Segment/YSD-439AR6B-35.pdf
 7 segments + 4 digits + 1 colon = 12 pins required for full control 
 */
// modified connexion by niq_ro from http://nicuflorica.blogspot.com
// for my Luckylight KW4-563ASA
// dataseet: http://www.tme.eu/ro/Document/dfc2efde2e22005fd28615e298ea2655/KW4-563XSA.pdf

int digit1 = 11; //PWM Display pin 12 (digit1 is common anonds A1 from right side)
int digit2 = 10; //PWM Display pin 9 (digit2 is  common A2)
int digit3 = 9; //PWM Display pin 8 (digit3 is common anods A3)
int digit4 = 6; //PWM Display pin 6 (digit4 is common anods, from left side)

//Pin mapping from Arduino to the ATmega DIP28 if you need it
//http://www.arduino.cc/en/Hacking/PinMapping
int segA = 2; //Display pin 11
int segB = 3; //Display pin 7
int segC = 4; //Display pin 4
int segD = 5; //Display pin 2
int segE = 12; //Display pin 1
int segF = 7; //Display pin 10
int segG = 8; //Display pin 5
int segDP = 13; // Display pin 3

#include <Wire.h>
#include "RTClib.h"
RTC_DS1307 RTC;

// Date and time functions using a DS1307 RTC connected via I2C and Wire lib
// original sketck from http://learn.adafruit.com/ds1307-real-time-clock-breakout-board-kit/
// add part with SQW=1Hz from http://tronixstuff.wordpress.com/2010/10/20/tutorial-arduino-and-the-i2c-bus/
// add part with manual adjust http://www.bristolwatch.com/arduino/arduino_ds1307.htm




byte SW0 = A0;
byte SW1 = A1;
byte SW2 = A2;

// use for hexa in zecimal conversion
int zh, uh, ore;
int zm, um, miniti;

void setup() {
  
 //  Serial.begin(57600);
  Wire.begin();
  RTC.begin();
// RTC.adjust(DateTime(__DATE__, __TIME__));
// if you need set clock... just remove // from line above this

// part code for flashing LED
Wire.beginTransmission(0x68);
Wire.write(0x07); // move pointer to SQW address
// Wire.write(0x00); // turns the SQW pin off
 Wire.write(0x10); // sends 0x10 (hex) 00010000 (binary) to control register - turns on square wave at 1Hz
// Wire.write(0x13); // sends 0x13 (hex) 00010011 (binary) 32kHz

Wire.endTransmission();

  if (! RTC.isrunning()) {
    Serial.println("RTC is NOT running!");
    // following line sets the RTC to the date & time this sketch was compiled
    RTC.adjust(DateTime(__DATE__, __TIME__));
  }
  
  
// dht.begin();

  pinMode(segA, OUTPUT);
  pinMode(segB, OUTPUT);
  pinMode(segC, OUTPUT);
  pinMode(segD, OUTPUT);
  pinMode(segE, OUTPUT);
  pinMode(segF, OUTPUT);
  pinMode(segG, OUTPUT);
  pinMode(segDP, OUTPUT);

  pinMode(digit1, OUTPUT);
  pinMode(digit2, OUTPUT);
  pinMode(digit3, OUTPUT);
  pinMode(digit4, OUTPUT);
  
//  pinMode(13, OUTPUT);

 Serial.begin(9600);
 Serial.println("test for niq_ro");

 pinMode(SW0, INPUT);  // for this use a slide switch
  pinMode(SW1, INPUT);  // N.O. push button switch
  pinMode(SW2, INPUT);  // N.O. push button switch

  digitalWrite(SW0, HIGH); // pull-ups on
  digitalWrite(SW1, HIGH);
  digitalWrite(SW2, HIGH);



}

void loop() {
digitalWrite(segDP, HIGH);
  DateTime now = RTC.now();
  int timp = now.hour()*100+now.minute();
//   int timp = (now.minute(), DEC);
//   displayNumber(12); // this is number to diplay
//   int timp = 1234;
  Serial.print(now.hour(), DEC);
  Serial.print(":");
  Serial.print(now.minute(), DEC);
  Serial.print(" -> ");
  Serial.print(timp);
  Serial.println(" !");

// display parts   
   for(int i = 250 ; i >0  ; i--) {
     if (timp >= 1000) displayNumber01(timp); 
     else displayNumber02(timp); 
   } 

   for(int i = 250 ; i >0  ; i--) {
     if (timp >= 1000) displayNumber03(timp); 
     else displayNumber04(timp); 
   } 

  if (!(digitalRead(SW0))) set_time(); // hold the switch to set time
} 


void set_time()   {
  byte minutes1 = 0;
  byte hours1 = 0;
  byte minutes = 0;
  byte hours = 0;

  while (!digitalRead(SW0))  // set time switch must be released to exit
  {
    minutes1=minutes;
    hours1=hours;
    
     
    while (!digitalRead(SW1)) // set minutes
    { 
     minutes++;  
   // converting hexa in zecimal:
    zh = hours / 16;
    uh = hours - 16 * zh ;
    ore = 10 * zh + uh; 
    zm = minutes / 16;
    um = minutes - 16 * zm ;
    miniti = 10 * zm + um; 
    
     for(int i = 20 ; i >0  ; i--) {
     displayNumber01(ore*100+miniti); 
     }

      
      if ((minutes & 0x0f) > 9) minutes = minutes + 6;
      if (minutes > 0x59) minutes = 0;
      Serial.print("Minutes = ");
      if (minutes >= 9) Serial.print("0");
      Serial.println(minutes, HEX);
    delay(150);    
    }

    while (!digitalRead(SW2)) // set hours
    { 
     hours++;          
     
   // converting hexa in zecimal:
    zh = hours / 16;
    uh = hours - 16 * zh ;
    ore = 10 * zh + uh; 
    zm = minutes / 16;
    um = minutes - 16 * zm ;
    miniti = 10 * zm + um; 
    
     for(int i = 20 ; i >0  ; i--) {
     displayNumber01(ore*100+miniti); 
     }
   
      
      if ((hours & 0x0f) > 9) hours =  hours + 6;
      if (hours > 0x23) hours = 0;
      Serial.print("Hours = ");
      if (hours <= 9) Serial.print("0");
      Serial.println(hours, HEX);
    delay(150);
    }

    Wire.beginTransmission(0x68); // activate DS1307
    Wire.write(0); // where to begin
    Wire.write(0x00);          //seconds
    Wire.write(minutes);          //minutes
    Wire.write(0x80 | hours);    //hours (24hr time)
    Wire.write(0x06);  // Day 01-07
    Wire.write(0x01);  // Date 0-31
    Wire.write(0x05);  // month 0-12
    Wire.write(0x09);  // Year 00-99
    Wire.write(0x10); // Control 0x10 produces a 1 HZ square wave on pin 7. 
    Wire.endTransmission();
  
    // converting hexa in zecimal:
    zh = hours / 16;
    uh = hours - 16 * zh ;
    ore = 10 * zh + uh; 
    zm = minutes / 16;
    um = minutes - 16 * zm ;
    miniti = 10 * zm + um; 
    
     for(int i = 20 ; i >0  ; i--) {
     displayNumber01(ore*100+miniti); 
     }
 //  delay(150);
    
  }
  
}



void displayNumber01(int toDisplay) {
#define DISPLAY_BRIGHTNESS  500

#define DIGIT_ON  HIGH
#define DIGIT_OFF  LOW

  for(int digit = 4 ; digit > 0 ; digit--) {

    //Turn on a digit for a short amount of time
    switch(digit) {
    case 1:
     digitalWrite(digit1, DIGIT_ON);
     digitalWrite(segDP, HIGH);
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(segDP, LOW);
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    }
    lightNumber(toDisplay % 10);
    toDisplay /= 10;
    delayMicroseconds(DISPLAY_BRIGHTNESS); 

     //Turn off all segments
    lightNumber(10); 

    //Turn off all digits
    digitalWrite(digit1, DIGIT_OFF);
    digitalWrite(digit2, DIGIT_OFF);
    digitalWrite(digit3, DIGIT_OFF);
    digitalWrite(digit4, DIGIT_OFF);
}
} 

void displayNumber02(int toDisplay) {
#define DISPLAY_BRIGHTNESS  500

#define DIGIT_ON  HIGH
#define DIGIT_OFF  LOW

  for(int digit = 4 ; digit > 0 ; digit--) {

    //Turn on a digit for a short amount of time
    switch(digit) {
    case 1:
     lightNumber(10); 
     digitalWrite(segDP, HIGH);
     break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(segDP, LOW);
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    }
    lightNumber(toDisplay % 10);
    toDisplay /= 10;
    delayMicroseconds(DISPLAY_BRIGHTNESS); 

     //Turn off all segments
    lightNumber(10); 

    //Turn off all digits
    digitalWrite(digit1, DIGIT_OFF);
    digitalWrite(digit2, DIGIT_OFF);
    digitalWrite(digit3, DIGIT_OFF);
    digitalWrite(digit4, DIGIT_OFF);
}
} 

void displayNumber03(int toDisplay) {
#define DISPLAY_BRIGHTNESS  500

#define DIGIT_ON  HIGH
#define DIGIT_OFF  LOW

  for(int digit = 4 ; digit > 0 ; digit--) {

    //Turn on a digit for a short amount of time
    switch(digit) {
    case 1:
     digitalWrite(digit1, DIGIT_ON);
     digitalWrite(segDP, HIGH);
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    }
    lightNumber(toDisplay % 10);
    toDisplay /= 10;
    delayMicroseconds(DISPLAY_BRIGHTNESS); 

     //Turn off all segments
    lightNumber(10); 

    //Turn off all digits
    digitalWrite(digit1, DIGIT_OFF);
    digitalWrite(digit2, DIGIT_OFF);
    digitalWrite(digit3, DIGIT_OFF);
    digitalWrite(digit4, DIGIT_OFF);
}
} 

void displayNumber04(int toDisplay) {
#define DISPLAY_BRIGHTNESS  500

#define DIGIT_ON  HIGH
#define DIGIT_OFF  LOW

  for(int digit = 4 ; digit > 0 ; digit--) {

    //Turn on a digit for a short amount of time
    switch(digit) {
    case 1:
     lightNumber(10); 
     digitalWrite(segDP, HIGH);
     break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      digitalWrite(segDP, HIGH);
      break;
    }
    lightNumber(toDisplay % 10);
    toDisplay /= 10;
    delayMicroseconds(DISPLAY_BRIGHTNESS); 

     //Turn off all segments
    lightNumber(10); 

    //Turn off all digits
    digitalWrite(digit1, DIGIT_OFF);
    digitalWrite(digit2, DIGIT_OFF);
    digitalWrite(digit3, DIGIT_OFF);
    digitalWrite(digit4, DIGIT_OFF);
}
} 


//Given a number, turns on those segments
//If number == 10, then turn off number
void lightNumber(int numberToDisplay) {

#define SEGMENT_ON  LOW
#define SEGMENT_OFF HIGH

  switch (numberToDisplay){

  case 0:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_OFF);
    break;

  case 1:
    digitalWrite(segA, SEGMENT_OFF);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    break;

  case 2:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 3:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 4:
    digitalWrite(segA, SEGMENT_OFF);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 5:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 6:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 7:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    break;

  case 8:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    break;

  case 9:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_ON);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    break;

  // all segment are ON
  case 10:
    digitalWrite(segA, SEGMENT_OFF);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    break;
  
  }
}

   I made a litle movie named manual adjust for RTC clock with Arduino and 7-segment LED display

Note: Original article in roumanian language is Afisaje LED cu 7 segmente si.. Arduino (IV)!!!

11.10.2016
   I correct sketch for display 10:00 case..

07.02.2017

    Now, I pun on my Github channel sketch for cathode comon display, see github.com/tehniq3/multiplexedclock