Nicu FLORICA (niq_ro): anod comun

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vineri, 20 septembrie 2024

Comanda afisaj led din 7 segmente cu modul i2c cu PCF8574 pentru afisaj alfanumeric LCD 1602/2004

Pentru un anumit proiect, am vrut sa controlez un afisaj cu un singur digit de 7-segmente folosind comunicatia i2c si am avut la indemana doar un modul folosit, in mod obisnuit, la afisajele alfanumerice LCD 1602 sau 2004.

Cautand pe internet, am gasit schema modulului la protosupplies.com:

din care se observa ca P3 nu este conectata direct, ci la comanda prin tranzistor a ledului de fundal, asa ca am testat pe un breadboard (2 de fapt) un mic montaj cu niste leduri

Am facut un test folosind informatiile din articolul 7-Segment LED Display PCF8574 I2C Arduino
doar ca eu am conectat singurul afisaj led gasit, unul de 1.2" cu catod comun direct, inseriind ledurile cu rezistente de 470Ω tinand cont si de informatiile de aici

Pentru afisajul cu catod comun, ledurile se aprind cand pe iesirea PCF-ului sunt 5V (iesire in HIGH), asa ca am transformat informatia in numar hexazecimal, folosind un calculator online, pentru a putea transmite informatia cu Arduino:

Pentru afisaje cu anod comun, alimentat din +5V, ledurile din segmente inseriate cu rezistente de limitare curent se conecteaza la iesirile PCF-ului si se aprind cand iesire corespunzatoare sunt in 0V (iesire in LOW), iar informatia in hexazecimal este

Dupa cum se constata, am pus iesirea P3 mereu in LOW (0), deoarece nu am acces direct fara o interventie pe placuta si programelul meu de test, este countdown_test1.ino

Am facut si 2 filmulete:

- numarator pe afisaj led din 7-segmente controlat cu interfata i2c (PCF8574)

- countdown on 7-segment led display drived by i2c interface (PCF8574)

21.09.2024

Pentru a depista adresa i2c a intefetei cu PCF8574 am folosit programiorul numit i2c_scanner (puteti gasi mai multe informatii in articolul de pe arduino.cc), gasind adresa 0x27.

Am facut "punte" (strap) la A0 si acum adresa este 0x26.

si am modificat programul, acesta devenind, countdown_test2.ino in care se defineste adresa la inceput si apoi este ca variabila.

22.09.2024

Am desenat schema de conectare pentru un afisaj

- cu catod comun (cum am testat eu)

- cu anod comun

duminică, 22 mai 2022

Sistem automat de iluminare alb/rosu functie de sens de deplasare locomotiva analogica (2)

Pregatind o veche locomotiva analogica sa devina digitala, am adaugat acesteia un sistem cu 4 leduri bicolore (alb-rosu) cu anod comun si 8 rezistente pentru a avea 2 leduri aprinse in alb (in fata) si 2 aprinse in rosu (in spate) cand se face deplasarea in fata, respectiv 2 leduri aprinse in rosu (in fata) si 2 aprinse in alb (in spate), cand se face deplasarea in spate... lucrarea nu este finalizata, dar sistemul are 3 fire, unul albastru, pentru un plus comun, un fir alb pentru aprinderea luminilor corespunzatoare deplasarii in fata si unul rosu pentru aprinderea luminilor corespunzatoare deplasarii in spate. Acest sistem fost descris in articolul Transformarea unui locomotive analogice intr-una digitala (2).

Intr-un articol trecut am conceput si testat un sistem cu led bicolor (alb-rosu) cu anod comun pentru a fi folosit la o locomotiva analogica (am reinventat roata, ca nu am cautat destul de atent pe net)

Deoarece spatul liber, la locomotiva pe care o detin si vreau sa fac teste cu sistemul digital, este mic o sa imi fie greu sa testez si pentru una analogica, am zis sa vad daca sistemul se poate adapta si pentru sistemul analogic (si, bineinteles ca, merge).

Teste ca locomotiva digitala, la care ma refeream, am facut, cu o placa adaptoare si decodorul + leduri puse deasupra boghiului, dupa cum se vede in articolul Transformarea unui locomotive analogice intr-una digitala (1)

Revenind la sistemul de iluminare automat pentru o locomotiva analogica, fata de schema testata pentru sistemul digital

necesita doar 2 diode in plus

Alimentand sistemul de 4 leduri la 15V, avem un consum de cca 60mA

- simulare deplasare in fata

- simulre deplasare in spate

PS: Schema se poate simplifica, reducand numarul de rezistente la 4:

Am facut si 2 filmulete:

1) cu descriere in limba romana

2) cu descriere in engleza

29.05.2021

Noul coleg, Virgil, a recablat firele pentru sistemul cu 4 leduri bicolore cu anod comun si doar 4 rezistente in carcasa de locomotiva micuta:

miercuri, 20 mai 2015

Termostat cu afisaj LED

english version

Fata de articolul anterior (Termostat cu 2 praguri de temperatura pe afisaj LED), de data aceasta am modificat sketch-urile sa am un termostat clasic, cu temperatura reglata si, in plus, sa pot regla histerezisul.
- temperatura masurata mai mica decat cea reglata:

- temperata reglata:

- histerezis:

- temperatura masurata mai mare decat cea reglata:

- temperatura masurata este in domeniul dorit:

Schema este aceeasi:

Pentru inceput, am folosit sketch-ul cu modificarea parametrilor fara a-i memora in EEPROM-ul microcontorlerului, pastrand si partea de corectie a citirii temperaturii si medierea cu valoarea anterioara; am facut si filmuletul Termostat cu Arduino care prezinta modul de functionare si reglare:

Sketch-ul folosit este:

// http://nicuflorica.blogspot.ro/2013/07/afisaje-led-cu-7-segmente-si-arduino-ii.html
/*
 6-13-2011
 Spark Fun Electronics 2011
 Nathan Seidle

 This code is public domain but you buy me a beer if you use this and we meet 
 someday (Beerware license).

 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

 This is an example of how to drive a 7 segment LED display from an ATmega
 without the use of current limiting resistors. This technique is very common 
 but requires some knowledge of electronics - you do run the risk of dumping 
 too much current through the segments and burning out parts of the display. 
 If you use the stock code you should be ok, but be careful editing the 
 brightness values.

 This code should work with all colors (red, blue, yellow, green) but the 
 brightness will vary from one color to the next because the forward voltage 
 drop of each color is different. This code was written and calibrated for the 
 red color.

 This code will work with most Arduinos but you may want to re-route some of 
 the pins.

 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

byte digit1 = 11; //PWM Display pin 12 (digit1 is common anonds A1 from right side)
byte digit2 = 10; //PWM Display pin 9 (digit2 is  common A2)
byte digit3 = 9; //PWM Display pin 8 (digit3 is common anods A3)
byte 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
byte segA = 2; //Display pin 11
byte segB = 3; //Display pin 7
byte segC = 4; //Display pin 4
byte segD = 5; //Display pin 2
byte segE = 12; //Display pin 1
byte segF = 7; //Display pin 10
byte segG = 8; //Display pin 5

byte dP = 13; // decimal point

#define LMPIN A0     // what pin we're LM35 is connected

#define BUT1 A1    // - switch
#define BUT2 A2    // + switch
#define BUT3 A3    // MENU switch

#define RECE A4    // output for lower temperature
#define CALD A5    // output for upper temperature
#define BINE A6    // output for ok temperature

int tset = 240;  // temperature set (x10)
int dt = 5;      // dt temperature

byte meniu = 0; // if MENIU = 0 is clasical 
                // if MENIU = 1 is for temperature set
                // if MENIU = 2 is for dt temperature 
float t, t0, t2, k;
 

void setup() {

  analogReference(INTERNAL); // for Uno (1,1V)
  //analogReference(INTERNAL1V1); // for Mega (1,1V)
  
  pinMode(segA, OUTPUT);
  pinMode(segB, OUTPUT);
  pinMode(segC, OUTPUT);
  pinMode(segD, OUTPUT);
  pinMode(segE, OUTPUT);
  pinMode(segF, OUTPUT);
  pinMode(segG, OUTPUT);

  pinMode(digit1, OUTPUT);
  pinMode(digit2, OUTPUT);
  pinMode(digit3, OUTPUT);
  pinMode(digit4, OUTPUT);
  
  pinMode(dP, OUTPUT);
  
  pinMode(BUT1, INPUT);
  pinMode(BUT2, INPUT);
  pinMode(BUT3, INPUT);

  pinMode(RECE, OUTPUT);
  pinMode(CALD, OUTPUT);
  pinMode(BINE, OUTPUT);

  digitalWrite(BUT1, HIGH); // pull-ups on
  digitalWrite(BUT2, HIGH);
  digitalWrite(BUT3, HIGH);

  digitalWrite(RECE, LOW);
  digitalWrite(CALD, LOW);
  digitalWrite(BINE, LOW);
  
 Serial.begin(9600);
 Serial.println("test for niq_ro");

k = 0.86;  // factor corectie citire la multiplexare
delay(100);
t = analogRead(A0);
t0 = t * 110 / 1023;  // pentru referinta interna de 1,1V;
t2 = t0;
}

void loop() {

  Serial.print("meniu = ");
  Serial.println(meniu);

  Serial.print("tset = ");
  Serial.println(tset/10);
  Serial.print("dt = ");
  Serial.println(dt/10);

if (digitalRead(BUT3) == LOW) 
{ meniu = meniu + 1;
delay(250);
}
if (meniu == 3) meniu = 0;

if (millis() < 2000) citire();
//  t = analogRead(LMPIN);
//  t0 = t *500 / 1023;
leduri();

  Serial.print(t);
  Serial.print("/1023 --> ");
  Serial.print("t = ");
  Serial.println(t0);



//displayNumber(t0*10);
    
if (meniu == 0) {
int numara = 0;
  while (meniu == 0) {
numara = numara + 1;
  if (numara == 1000)
    {
//  float t = analogRead(LMPIN);
//  float t0 = t *500 / 1023;
citire();
t0 = (t0 + t2) /2;
leduri();
 // delay(5);
  numara = 0;
  Serial.print("t = ");
  Serial.println(t0);
//  displayNumber(t0*10); // this is number to diplay
    }
  te(t0*10); // this is number to diplay
  t2 = t0;
if (digitalRead(BUT3) == LOW) 
{ meniu = 1;
delay(250);
}
//Serial.print("t = ");
//Serial.println(t0);
//delay(5);
} 
delay(5);  
}



if (meniu == 1) {
   while (meniu == 1) {
//     minim(tset/10); // this is number to diplay
   teset(tset);
   if (digitalRead(BUT1) == LOW)
  { tset = tset - 1; 
  delay(250);
  }
   if (digitalRead(BUT2) == LOW)
  { tset = tset + 1;
  delay(250);
  }
  if (digitalRead(BUT3) == LOW) 
  { meniu = 2;
  delay(250);
  }
//  delay(15);
     }
  Serial.print("tset = ");
  Serial.println(tset/10);
   delay (100);
}

if (meniu == 2) {
 // if (tmax <= tmin) tmax = tmin + 10;
   while (meniu ==2) {
 //    maxim(dt/10); // this is number to diplay
     dete(dt); // this is number to diplay
   if (digitalRead(BUT1) == LOW) 
   { dt = dt - 1;
   delay(250);
  }
   if (digitalRead(BUT2) == LOW) 
   { dt = dt + 1;
   delay(250);
  }
   if (digitalRead(BUT3) == LOW) 
   { meniu = 0;
   delay(250);
  }
//   delay(15);
if (dt < 1) dt = 1;
    }
  Serial.print("dt = ");
  Serial.println(dt/10);

    delay(100);
}
}
//Given a number, we display 10:22
//After running through the 4 numbers, the display is left turned off

//Display brightness
//Each digit is on for a certain amount of microseconds
//Then it is off until we have reached a total of 20ms for the function call
//Let's assume each digit is on for 1000us
//Each digit is on for 1ms, there are 4 digits, so the display is off for 16ms.
//That's a ratio of 1ms to 16ms or 6.25% on time (PWM).
//Let's define a variable called brightness that varies from:
//5000 blindingly bright (15.7mA current draw per digit)
//2000 shockingly bright (11.4mA current draw per digit)
//1000 pretty bright (5.9mA)
//500 normal (3mA)
//200 dim but readable (1.4mA)
//50 dim but readable (0.56mA)
//5 dim but readable (0.31mA)
//1 dim but readable in dark (0.28mA)



void dete(int toDisplay) {
#define DISPLAY_BRIGHTNESS  750

#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);
      lightNumber(15); // display degree symbol
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;

    case 2:
      digitalWrite(digit2, DIGIT_ON);
       digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
   case 3:
      digitalWrite(digit3, DIGIT_ON);
//      digitalWrite(13, HIGH);
//      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
   case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(12); // display C letter
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
    }
     //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 te(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(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(12); // display C letter
      digitalWrite(13, 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);
    digitalWrite(13, 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);
    digitalWrite(13, 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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, 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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    break;
  
  // degree symbol made by niq_ro
  case 11:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    digitalWrite(13, SEGMENT_OFF);
    break;

  // C letter made by niq_ro
  case 12:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;
  
  // c letter made by niq_ro
  case 13:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    digitalWrite(13, SEGMENT_OFF);
    break;

  case 14:  // lower line (d segment)
    digitalWrite(segA, SEGMENT_OFF);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;

case 15:  // upper line (a segment)
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;
    
  }
}


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

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



void teset(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(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(13); // display C letter
      digitalWrite(dP, 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);

}
} 

float citire() {
  t = analogRead(A0);
  t0 = t * k *110 / 1023;  // pentru referinta interna de 1,1V;
//  t0 = t *500 / 1023;
  return t0;
}

Ulterior, am pus si memorarea valorilor reglate, dupa cum se vede si in filmuletul Termostat cu Arduino (2)

Sketch-ul folosit este:

// http://nicuflorica.blogspot.ro/2013/07/afisaje-led-cu-7-segmente-si-arduino-ii.html
// http://nicuflorica.blogspot.ro/2015/05/termostat-cu-2-praguri-de-temperatura.html
/*
 6-13-2011, Spark Fun Electronics 2011, Nathan Seidle

 This code is public domain but you buy me a beer if you use this and we meet 
 someday (Beerware license).

 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

 This is an example of how to drive a 7 segment LED display from an ATmega
 without the use of current limiting resistors. This technique is very common 
 but requires some knowledge of electronics - you do run the risk of dumping 
 too much current through the segments and burning out parts of the display. 
 If you use the stock code you should be ok, but be careful editing the 
 brightness values.

 This code should work with all colors (red, blue, yellow, green) but the 
 brightness will vary from one color to the next because the forward voltage 
 drop of each color is different. This code was written and calibrated for the 
 red color.

 This code will work with most Arduinos but you may want to re-route some of 
 the pins.

 7 segments
 4 digits
 1 colon
 =
 12 pins required for full control 

 */
// modified connexion by niq_ro from http://nicuflorica.blogspot.com
// http://arduinotehniq.blogspot.com/
// for my Luckylight KW4-563ASA
// dataseet: http://www.tme.eu/ro/Document/dfc2efde2e22005fd28615e298ea2655/KW4-563XSA.pdf

byte digit1 = 11; //PWM Display pin 12 (digit1 is common anonds A1 from right side)
byte digit2 = 10; //PWM Display pin 9 (digit2 is  common A2)
byte digit3 = 9; //PWM Display pin 8 (digit3 is common anods A3)
byte 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
byte segA = 2; //Display pin 11
byte segB = 3; //Display pin 7
byte segC = 4; //Display pin 4
byte segD = 5; //Display pin 2
byte segE = 12; //Display pin 1
byte segF = 7; //Display pin 10
byte segG = 8; //Display pin 5

byte dP = 13; // decimal point

#define LMPIN A0     // what pin we're LM35 is connected

#define BUT1 A1    // - switch
#define BUT2 A2    // + switch
#define BUT3 A3    // MENU switch

#define RECE A4    // output for lower temperature
#define CALD A5    // output for upper temperature
#define BINE A6    // output for ok temperature

//int tset = 240;  // temperature set (x10)
//int dt = 5;      // dt temperature

byte meniu = 0; // if MENIU = 0 is clasical 
                // if MENIU = 1 is for temperature set
                // if MENIU = 2 is for dt temperature 
float t, t0, t2, k;
int tset, tset1, tset2, dt; 

// http://tronixstuff.com/2011/03/16/tutorial-your-arduinos-inbuilt-eeprom/
#include <EEPROM.h>


void setup() {
 
  analogReference(INTERNAL); // for Uno (1,1V)
  //analogReference(INTERNAL1V1); // for Mega (1,1V)

// just first time... after must put commnent (//)
// EEPROM.write(101,0);    
// EEPROM.write(102,245);
// EEPROM.write(103,5);
  
  
tset1 = EEPROM.read(101);
tset2 = EEPROM.read(102);
tset = 256 * tset1 + tset2;  // recover the number
dt = EEPROM.read(103);

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

  pinMode(digit1, OUTPUT);
  pinMode(digit2, OUTPUT);
  pinMode(digit3, OUTPUT);
  pinMode(digit4, OUTPUT);
  
  pinMode(dP, OUTPUT);
  
  pinMode(BUT1, INPUT);
  pinMode(BUT2, INPUT);
  pinMode(BUT3, INPUT);

  pinMode(RECE, OUTPUT);
  pinMode(CALD, OUTPUT);
  pinMode(BINE, OUTPUT);

  digitalWrite(BUT1, HIGH); // pull-ups on
  digitalWrite(BUT2, HIGH);
  digitalWrite(BUT3, HIGH);

  digitalWrite(RECE, LOW);
  digitalWrite(CALD, LOW);
  digitalWrite(BINE, LOW);
  
 Serial.begin(9600);
 Serial.println("test for niq_ro");

k = 0.86;  // factor corectie citire la multiplexare
delay(100);
t = analogRead(A0);
t0 = t * 110 / 1023;  // pentru referinta interna de 1,1V;
t2 = t0;
}

void loop() {

  Serial.print("meniu = ");
  Serial.println(meniu);

  Serial.print("tset = ");
  Serial.println(tset/10);
  Serial.print("dt = ");
  Serial.println(dt/10);

if (digitalRead(BUT3) == LOW) 
{ meniu = meniu + 1;
delay(250);
}
if (meniu == 3) meniu = 0;

//if (millis() < 2000) citire();
//  t = analogRead(LMPIN);
//  t0 = t *500 / 1023;
leduri();

  Serial.print(t);
  Serial.print("/1023 --> ");
  Serial.print("t = ");
  Serial.println(t0);



//displayNumber(t0*10);
    
if (meniu == 0) {
int numara = 0;
  while (meniu == 0) {
numara = numara + 1;
  if (numara == 1000)
    {
//  float t = analogRead(LMPIN);
//  float t0 = t *500 / 1023;
citire();
t0 = (t0 + t2) /2;
leduri();
 // delay(5);
  numara = 0;
  Serial.print("t = ");
  Serial.println(t0);
//  displayNumber(t0*10); // this is number to diplay
    }
  te(t0*10); // this is number to diplay
  t2 = t0;
if (digitalRead(BUT3) == LOW) 
{ meniu = 1;
delay(250);
}
//Serial.print("t = ");
//Serial.println(t0);
//delay(5);
} 
delay(5);  
}



if (meniu == 1) {
   while (meniu == 1) {
//     minim(tset/10); // this is number to diplay
   teset(tset);
   if (digitalRead(BUT1) == LOW)
  { tset = tset - 1; 
  delay(250);
  }
   if (digitalRead(BUT2) == LOW)
  { tset = tset + 1;
  delay(250);
  }
  if (digitalRead(BUT3) == LOW) 
  { meniu = 2;
  delay(250);
  }
//  delay(15);
     }
     // scriu in memorie temperatura dorita
//tset1 = tset % 256;
//tset1 = tset /= 256;
//  Serial.print("tset1z = ");
//  Serial.println(tset1);
//  Serial.print("tset2u = ");
//  Serial.println(tset2);

tset1 = tset / 256;
tset2 = tset - tset1 * 256;
EEPROM.write(101, tset1);  // partea intreaga
EEPROM.write(102, tset2);   // rest
  Serial.print("tset1z = ");
  Serial.println(tset1);
  Serial.print("tset2u = ");
  Serial.println(tset2);
  
  Serial.print("tset = ");
  Serial.println(tset/10);
   delay (100);
}

if (meniu == 2) {
 // if (tmax <= tmin) tmax = tmin + 10;
   while (meniu ==2) {
 //    maxim(dt/10); // this is number to diplay
     dete(dt); // this is number to diplay
   if (digitalRead(BUT1) == LOW) 
   { dt = dt - 1;
   delay(250);
  }
   if (digitalRead(BUT2) == LOW) 
   { dt = dt + 1;
   delay(250);
  }
   if (digitalRead(BUT3) == LOW) 
   { meniu = 0;
   delay(250);
  }
//   delay(15);
if (dt < 1) dt = 1;
    }
    
  EEPROM.write(103,dt);      
  Serial.print("dt = ");
  Serial.println(dt/10);

    delay(100);
}
}
//Given a number, we display 10:22
//After running through the 4 numbers, the display is left turned off

//Display brightness
//Each digit is on for a certain amount of microseconds
//Then it is off until we have reached a total of 20ms for the function call
//Let's assume each digit is on for 1000us
//Each digit is on for 1ms, there are 4 digits, so the display is off for 16ms.
//That's a ratio of 1ms to 16ms or 6.25% on time (PWM).
//Let's define a variable called brightness that varies from:
//5000 blindingly bright (15.7mA current draw per digit)
//2000 shockingly bright (11.4mA current draw per digit)
//1000 pretty bright (5.9mA)
//500 normal (3mA)
//200 dim but readable (1.4mA)
//50 dim but readable (0.56mA)
//5 dim but readable (0.31mA)
//1 dim but readable in dark (0.28mA)



void dete(int toDisplay) {
#define DISPLAY_BRIGHTNESS  750

#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);
      lightNumber(15); // display degree symbol
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;

    case 2:
      digitalWrite(digit2, DIGIT_ON);
       digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
   case 3:
      digitalWrite(digit3, DIGIT_ON);
//      digitalWrite(13, HIGH);
//      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
   case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(12); // display C letter
      delayMicroseconds(DISPLAY_BRIGHTNESS); 
      break;
    }
     //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 te(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(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(12); // display C letter
      digitalWrite(13, 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);
    digitalWrite(13, 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);
    digitalWrite(13, 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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, 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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    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);
    digitalWrite(13, SEGMENT_OFF);
    break;
  
  // degree symbol made by niq_ro
  case 11:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_ON);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    digitalWrite(13, SEGMENT_OFF);
    break;

  // C letter made by niq_ro
  case 12:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_ON);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;
  
  // c letter made by niq_ro
  case 13:
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_ON);
    digitalWrite(segG, SEGMENT_ON);
    digitalWrite(13, SEGMENT_OFF);
    break;

  case 14:  // lower line (d segment)
    digitalWrite(segA, SEGMENT_OFF);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_ON);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;

case 15:  // upper line (a segment)
    digitalWrite(segA, SEGMENT_ON);
    digitalWrite(segB, SEGMENT_OFF);
    digitalWrite(segC, SEGMENT_OFF);
    digitalWrite(segD, SEGMENT_OFF);
    digitalWrite(segE, SEGMENT_OFF);
    digitalWrite(segF, SEGMENT_OFF);
    digitalWrite(segG, SEGMENT_OFF);
    digitalWrite(13, SEGMENT_OFF);
    break;
    
  }
}


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

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



void teset(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(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
   case 2:
      digitalWrite(digit2, DIGIT_ON);
      digitalWrite(13, LOW);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 3:
      digitalWrite(digit3, DIGIT_ON);
      digitalWrite(13, HIGH);
      lightNumber(toDisplay % 10);
      toDisplay /= 10;
      break;
    case 4:
      digitalWrite(digit4, DIGIT_ON);
      lightNumber(13); // display C letter
      digitalWrite(dP, 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);

}
} 

float citire() {
  t = analogRead(A0);
  t0 = t * k *110 / 1023;  // pentru referinta interna de 1,1V;
//  t0 = t *500 / 1023;
  return t0;
}

Am facut si un filmulet in engleza, numit Arduino thermostat

PS: La prima incarcare a sketch-ului trebuie sa scriem niste valori apropiate de cele dorite in memoria interna a microcontrolerului:

apoi se anuleaza cele 3 linii (se "comenteaza") si se reincarca sketch-ul:

Testele au fost facute cu o placa Arduino Uno si vom gasi in sketch

dar functioneaza foarte bine si cu o placa Arduino Mega, trebuind anulata ("comentata") prima linie si activata cea de-a doua:

Daca se doreste conectarea unui releu (la iesirea unde este comectat LED-ul albastru), care sa comande pornirea unei centrale sau a unei rezistente de incalzire, subrutina leduri trebuie schimbata un pic:

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);
}
}
}

si trebuie definita la inceputul sketch-ului variabila int pornire; iar la setup pornire = 0; !!!
Puteti descarca sketch-ul cu modificari de la https://github.com/tehniq3 !
In filmuletul Termostat cu Arduino (3) se vede modul de functionare..