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[on:]

Hi all. I am in the process of making my first 'proper' arduino project. I'm putting together a thermstat to switch on my boiler at a set temperature. I am not experienced at all with programming so the source code has taken a while to get working as I wanted it too.

Basically I am reading the value from a pot, mapping it to a temperature range, and using this value to switch a digital output if the measured temperature is less than the desired. It does this with else, if statements.

I have also added some maths to take the average of a few temp measurements around the house, so I would like to use a switch and lets say, if its value is closed / high, the measured temperature will switch to the average reading, and if its open / low the measured temperature will switch to the single local sensor reading.

I have been trying to get this to work by reading a digital input, deciding if the value is low or high and then using that high or low variable in the 'else if' statement that switches the output, but my efforts have failed because the output pin stays active all the time

I hope its only something simple, but if someone could point it out it would save me a lot of headaches

the first lot of code below is the edited (non working) code as explained above, and the second lot is before i started to try and read the switch and stopped it working in case I have really messed it up.

Code:

/*
 The circuit:
 * LDR connected to analog pin 0.
 * LED / transistor connected from digital pin 3 to ground
 
 * LCD RS pin to digital pin 7
 * LCD EN pin to digital pin 8
 * LCD D4 pin to digital pin 9
 * LCD D5 pin to digital pin 10
 * LCD D6 pin to digital pin 11
 * LCD D7 pin to digital pin 12
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 * LCD LED+ (15) pin transistor
 * LCD LED- (16) to ground
 
 * Thermisor divider 1 output to analog pin 1
 * Thermisor divider 2 output to analog pin 2
 */

// These constants won't change.  They're used to give names
// to the pins used:
const int select = A0;      // Analog input pin that the temp select pot is attached to
const int analogInPin = A1;      // Analog input pin that the lDR is attached to
const int analogOutPin = 3;      // Analog (PWM) output pin that the BACKLIGHT is attached to
const int coldPin = 2;      // Digital output pin that the COLD RELAY is attached to
const int frostPin = 4;      // Digital output pin that the frost warning is attached to
//const int hotPin = 5;      // Digital output pin that the HOT LED is attached to
const int out = A2;         // Analog input that the 'Out' thermistor is connected too
const int hall = A3;         // Analog input that the 'Hall' thermistor is connected too
const int bed = A4;         // Analog input that the 'Bed' thermistor is connected too
const int bath = A5;         // Analog input that the 'Bath' thermistor is connected too
const int lounge = A6;         // Analog input that the 'Lounge' thermistor is connected too
const int kitchen = A7;         // Analog input that the 'Kitchen' thermistor is connected too
const int modeButton = 6;      //Digital input that the mode button is connected too


//Parameters

const int coldTemp = 10;      // lower do something threshold in degrees c
const int hotTemp = 20;       // upper do something threshold in degrees c
const int setPointLow = 5;    // lowest temp available
const int setPointHigh = 25;  // highest temp available
const int frostWarning = 10;  // outside frost warning threshold
float hysteresis = 0.4;       // error margin
float averageTemp = 0;         //place to store average reading
float desired = 0;         //place to store selected mode
float buttonState = 0;         //place to store current selected mode


const int minLight = 80;        // at or below this light level, use minimum backlight intensity
const int maxLight = 920;        // at or above this light level, use maximum backlight intensity
const int minBacklight = 5;      // lowest backlight intensity to use
const int maxBacklight = 255;    // highest backlight intensity to use

// include the library code:
#include <LiquidCrystal.h>
#include <math.h>

#define NUMSAMPLES 64


double convert(double RawADC)
{
  double Temp;
  Temp = log(((10240000/RawADC) - 10000));
  Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
  Temp = Temp - 273.15;            // Convert Kelvin to Celcius

  return Temp;
}

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

int sensorValue1 = 0;      // value read from the pot
int sensorValue = 0;       // value read from the LDR
int outputValue = 0;       // value output to the PWM (analog out)
int setPoint = 0;          // value set point



void setup()
{
  lcd.begin(20, 4);
  delay(100);
  pinMode(3, OUTPUT);   //LCD BACKLIGHT
  pinMode(coldPin, OUTPUT);   //COLD WARNING
  pinMode(frostPin, OUTPUT);   //OUTSIDE FROST WARNING
  pinMode(modeButton, INPUT);   //MODE SELECT BUTTON
}

void loop()
{
  // LDR PART
  int sum = 0;
  for (int i=0; i<16; i++) // do some averaging too
  {
    sum += analogRead(analogInPin);
  }
  sensorValue = sum/16;

  // map it to the range[0..255] of the analog out
  outputValue = sensorValue/4;   // easier than map function
  outputValue = map(constrain(sensorValue, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

  // change the analog out value:
  analogWrite(analogOutPin, outputValue);          


  // temp select part

  sensorValue1 = analogRead(select);
  setPoint = map (sensorValue1, 0, 1023, setPointLow, setPointHigh);





  // TEMPERATURE PART
  uint8_t i;
  float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6
  for (i=0; i< NUMSAMPLES; i++)            
  {
    average += analogRead(out);
    average1 += analogRead(hall);
    average2 += analogRead(bed);
    average3 += analogRead(bath);
    average4 += analogRead(lounge);
    average5 += analogRead(kitchen);
    delay(10);
  }
  average /= NUMSAMPLES;
  average1 /= NUMSAMPLES;
  average2 /= NUMSAMPLES;
  average3 /= NUMSAMPLES;
  average4 /= NUMSAMPLES;
  average5 /= NUMSAMPLES;

  double outTemp = convert(average);
  double hallTemp = convert(average1);
  double bedTemp = convert(average2);
  double bathTemp = convert(average3);
  double loungeTemp = convert(average4);
  double kitchenTemp = convert(average5);


  //PRINT HALL TEMP AND DO THERMOSTAT DUTIES

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print ("Hal: ");
  lcd.print(hallTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");




 buttonState = digitalRead(modeButton);
 
  if(buttonState == HIGH)
    desired = 0;
  else if (buttonState == LOW)
    desired = 1;






  if(desired = 0 && hallTemp <setPoint - hysteresis)
    digitalWrite(coldPin, HIGH);   // set the LED on
  else if (desired = 0 && hallTemp >setPoint + hysteresis)
    digitalWrite(coldPin, LOW);   // set the LED off
  else if (desired = 1 && averageTemp >setPoint + hysteresis)
    digitalWrite(coldPin, HIGH);   // set the LED off
  else if (desired = 1 && averageTemp >setPoint + hysteresis)
    digitalWrite(coldPin, LOW);   // set the LED off
  
    
    
    



  //print set temp
  lcd.setCursor(11,4);
  lcd.print ("Set: ");


  if(setPoint <setPointLow +1)
    lcd.print((char)42);
  else if (setPoint >setPointLow)
    lcd.print(setPoint);

  //PRINT LOUNGE TEMP
  lcd.setCursor(11,0);
  lcd.print ("Lng: ");
  lcd.print(loungeTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT KITCHEN TEMP
  lcd.setCursor(0,1);
  lcd.print ("Kit: ");
  lcd.print(kitchenTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT BED TEMP
  lcd.setCursor(11,1);
  lcd.print ("Bed: ");
  lcd.print(bedTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT BATH TEMP
  lcd.setCursor(0,2);
  lcd.print ("Bth: ");
  lcd.print(bathTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT OUT TEMP
  lcd.setCursor(0,4);
  lcd.print ("Out: ");
  lcd.print(outTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  if(outTemp <frostWarning - hysteresis)
    digitalWrite(frostPin, HIGH);                    // set the LED on
  else if (outTemp >frostWarning + hysteresis)
    digitalWrite(frostPin, LOW);                     // set the LED off
    
    
    
      //PRINT average temp
      
  averageTemp = hallTemp + bedTemp + bathTemp + loungeTemp + kitchenTemp;
  averageTemp = averageTemp/5;
  
  lcd.setCursor(11,2);
  lcd.print ("Ave: ");
  lcd.print(averageTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");



  delay(1000);                    
}

[Reply #1 on:]

Code:

/*
 The circuit:
 * LDR connected to analog pin 0.
 * LED / transistor connected from digital pin 3 to ground
 
 * LCD RS pin to digital pin 7
 * LCD EN pin to digital pin 8
 * LCD D4 pin to digital pin 9
 * LCD D5 pin to digital pin 10
 * LCD D6 pin to digital pin 11
 * LCD D7 pin to digital pin 12
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 * LCD LED+ (15) pin transistor
 * LCD LED- (16) to ground
 
 * Thermisor divider 1 output to analog pin 1
 * Thermisor divider 2 output to analog pin 2
 */

// These constants won't change.  They're used to give names
// to the pins used:
const int select = A0;      // Analog input pin that the temp select pot is attached to
const int analogInPin = A1;      // Analog input pin that the lDR is attached to
const int analogOutPin = 3;      // Analog (PWM) output pin that the BACKLIGHT is attached to
const int coldPin = 2;      // Digital output pin that the COLD RELAY is attached to
const int frostPin = 4;      // Digital output pin that the frost warning is attached to
//const int hotPin = 5;      // Digital output pin that the HOT LED is attached to
const int out = A2;         // Analog input that the 'Out' thermistor is connected too
const int hall = A3;         // Analog input that the 'Hall' thermistor is connected too
const int bed = A4;         // Analog input that the 'Bed' thermistor is connected too
const int bath = A5;         // Analog input that the 'Bath' thermistor is connected too
const int lounge = A6;         // Analog input that the 'Lounge' thermistor is connected too
const int kitchen = A7;         // Analog input that the 'Kitchen' thermistor is connected too


//Parameters

const int coldTemp = 10;      // lower do something threshold in degrees c
const int hotTemp = 20;       // upper do something threshold in degrees c
const int setPointLow = 5;    // lowest temp available
const int setPointHigh = 25;  // highest temp available
const int frostWarning = 10;  // outside frost warning threshold
float hysteresis = 0.4;       // error margin
float averageTemp = 0;         //place to store average reading


const int minLight = 80;        // at or below this light level, use minimum backlight intensity
const int maxLight = 920;        // at or above this light level, use maximum backlight intensity
const int minBacklight = 5;      // lowest backlight intensity to use
const int maxBacklight = 255;    // highest backlight intensity to use

// include the library code:
#include <LiquidCrystal.h>
#include <math.h>

#define NUMSAMPLES 64


double convert(double RawADC)
{
  double Temp;
  Temp = log(((10240000/RawADC) - 10000));
  Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
  Temp = Temp - 273.15;            // Convert Kelvin to Celcius

  return Temp;
}

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

int sensorValue1 = 0;      // value read from the pot
int sensorValue = 0;       // value read from the LDR
int outputValue = 0;       // value output to the PWM (analog out)
int setPoint = 0;          // value set point



void setup()
{
  lcd.begin(20, 4);
  delay(100);
  pinMode(3, OUTPUT);   //LCD BACKLIGHT
  pinMode(coldPin, OUTPUT);   //COLD WARNING
  pinMode(frostPin, OUTPUT);   //OUTSIDE FROST WARNING
}

void loop()
{
  // LDR PART
  int sum = 0;
  for (int i=0; i<16; i++) // do some averaging too
  {
    sum += analogRead(analogInPin);
  }
  sensorValue = sum/16;

  // map it to the range[0..255] of the analog out
  outputValue = sensorValue/4;   // easier than map function
  outputValue = map(constrain(sensorValue, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

  // change the analog out value:
  analogWrite(analogOutPin, outputValue);          


  // temp select part

  sensorValue1 = analogRead(select);
  setPoint = map (sensorValue1, 0, 1023, setPointLow, setPointHigh);





  // TEMPERATURE PART
  uint8_t i;
  float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6
  for (i=0; i< NUMSAMPLES; i++)            
  {
    average += analogRead(out);
    average1 += analogRead(hall);
    average2 += analogRead(bed);
    average3 += analogRead(bath);
    average4 += analogRead(lounge);
    average5 += analogRead(kitchen);
    delay(10);
  }
  average /= NUMSAMPLES;
  average1 /= NUMSAMPLES;
  average2 /= NUMSAMPLES;
  average3 /= NUMSAMPLES;
  average4 /= NUMSAMPLES;
  average5 /= NUMSAMPLES;

  double outTemp = convert(average);
  double hallTemp = convert(average1);
  double bedTemp = convert(average2);
  double bathTemp = convert(average3);
  double loungeTemp = convert(average4);
  double kitchenTemp = convert(average5);


  //PRINT HALL TEMP AND DO THERMOSTAT DUTIES

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print ("Hal: ");
  lcd.print(hallTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  if(hallTemp <setPoint - hysteresis)
    digitalWrite(coldPin, HIGH);   // set the LED on
  else if (hallTemp >setPoint + hysteresis)
    digitalWrite(coldPin, LOW);   // set the LED off



  //print set temp
  lcd.setCursor(11,4);
  lcd.print ("Set: ");


  if(setPoint <setPointLow +1)
    lcd.print((char)42);
  else if (setPoint >setPointLow)
    lcd.print(setPoint);

  //PRINT LOUNGE TEMP
  lcd.setCursor(11,0);
  lcd.print ("Lng: ");
  lcd.print(loungeTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT KITCHEN TEMP
  lcd.setCursor(0,1);
  lcd.print ("Kit: ");
  lcd.print(kitchenTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT BED TEMP
  lcd.setCursor(11,1);
  lcd.print ("Bed: ");
  lcd.print(bedTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT BATH TEMP
  lcd.setCursor(0,2);
  lcd.print ("Bth: ");
  lcd.print(bathTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //PRINT OUT TEMP
  lcd.setCursor(0,4);
  lcd.print ("Out: ");
  lcd.print(outTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  if(outTemp <frostWarning - hysteresis)
    digitalWrite(frostPin, HIGH);                    // set the LED on
  else if (outTemp >frostWarning + hysteresis)
    digitalWrite(frostPin, LOW);                     // set the LED off
    
    
    
      //PRINT average temp
      
  averageTemp = hallTemp + bedTemp + bathTemp + loungeTemp + kitchenTemp;
  averageTemp = averageTemp/5;
  
  lcd.setCursor(11,2);
  lcd.print ("Ave: ");
  lcd.print(averageTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");



  delay(1000);                    
}

[Reply #2 on:]

Code:

  int sum = 0;
  for (int i=0; i<16; i++) // do some averaging too
  {
    sum += analogRead(analogInPin);
  }
  sensorValue = sum/16;

Great names. We can tell exactly what is going on. Not. What is this supposed to be doing?

What is connected to the analogInPin? What does some generic sensorValue mean?

Code:

const int analogInPin = A1;      // Analog input pin that the lDR is attached to

So, why doesn't the name reflect the use?

Code:

  outputValue = sensorValue/4;   // easier than map function
  outputValue = map(constrain(sensorValue, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

  // change the analog out value:
  analogWrite(analogOutPin, outputValue);           

minLight, maxLight, minBackLight, and maxBackLight are good names. outputValue is a lousy name, as is analogOutPin.

Code:

  // temp select part

  sensorValue1 = analogRead(select);
  setPoint = map (sensorValue1, 0, 1023, setPointLow, setPointHigh);

More mixing of good names and lousy names. It's hard to follow what this is supposed to do, with generic names.

What is connected to the select pin?

Code:

Is this really necessary?

Code:

  float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6

Did you say something? I couldn't hear you over this code screaming ARRAY!

Code:

  average /= NUMSAMPLES;
  average1 /= NUMSAMPLES;
  average2 /= NUMSAMPLES;
  average3 /= NUMSAMPLES;
  average4 /= NUMSAMPLES;
  average5 /= NUMSAMPLES;

Why are these not numbered 1 to 6?

Code:

    lcd.print((char)42);

as opposed to lcd.print('*');?

Code:

  outputValue = sensorValue/4;   // easier than map function
  outputValue = map(constrain(sensorValue, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

You assign outputValue a value, then assign it another value. OK.

Code:

buttonState = digitalRead(modeButton);

Wouldn't the modeButton (pin) define the mode?

Code:

  if(buttonState == HIGH)
    desired = 0;
  else if (buttonState == LOW)
    desired = 1;

So, after all this, desired = !digitalRead(modeButton). Why not just code that?

After all that, it isn't clear what part of the code you are having problems with? What doesn't works as you want?

[Reply #3 on:]

Paul missed one:

Code:

  if(desired = 0 && hallTemp <setPoint - hysteresis)

That makes desired become zero. Better read up on the difference between = and ==.

[Reply #4 on:]

excellent, it is working as I hoped now thanks for the help. This was the crucial bit I had wrong..

Code:

desired = digitalRead(modeButton);

  if(desired == HIGH && hallTemp <setPoint - hysteresis)
    digitalWrite(coldPin, HIGH);   // set the LED on
  else if (desired == HIGH && hallTemp >setPoint + hysteresis)
    digitalWrite(coldPin, LOW);   // set the LED off
  else if (desired == LOW && averageTemp <setPoint + hysteresis)
    digitalWrite(coldPin, HIGH);   // set the LED off
  else if (desired == LOW && averageTemp >setPoint + hysteresis)
    digitalWrite(coldPin, LOW);   // set the LED off

while I very much appreciate all the advice and the time you took to compose a reply, there is no need to be sarcastic. I am aware my code is far from perfect and could be greatly improved which is something I plan to work on - I have little experience with programming.

I'm not sure how I could link these together?

Code:

outputValue = sensorValue/4;   // easier than map function
  outputValue = map(constrain(sensorValue, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

I have looked at arrays before in brief detail but I not sure how this could be changed into one?

Code:

float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6

I understand all of your other points and I will go though and amend my code.

Thanks again

-Dan

[Reply #5 on:]

I have looked at arrays before in brief detail but I not sure how this could be changed into one?

Code:

float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6

becomes

Code:

   float average[6];
  for(int i=0; i<6; i++)
  {
     average[i] /= NUMSAMPLES;
  }

[Reply #6 on:]

Without meaning to be annoying something a little easier to maintain

Code:

float average[NUMSAMPLES];

for ( int i = 0; i < NUMSAMPLES; i++ )
{
average[i] /= NUMSAMPLES;
}

Or less often used but generally faster:

Code:

for ( int i = NUMSAMPLES; i--; )
{
average[i] /= NUMSAMPLES;
}

[Reply #7 on:]

something a little easier to maintain

True, but lets get OP to start using arrays first, before introducing all the subtleties that will trip him or her later.

[Reply #8 on:]

I have been trying for a while but can't get the array working. When I replace the old with the new code in your post I get errors on the next bit of code stating all the averages, average4.. were not declared in this scope? Not sure how I declare them?

[Reply #9 on:]

When I replace the old with the new code in your post I get errors on the next bit of code stating all the averages, average4.. were not declared in this scope? Not sure how I declare them?

Show us the code and the errors.

[Reply #10 on:]

I have looked at arrays before in brief detail but I not sure how this could be changed into one?

Code:

float average = 0;                     //input1
  float average1 = 0;                    //input2
  float average2 = 0;                    //input3
  float average3 = 0;                    //input4
  float average4 = 0;                    //input5
  float average5 = 0;                    //input6

becomes

Code:

   float average[6];
  for(int i=0; i<6; i++)
  {
     average[i] /= NUMSAMPLES;
  }

Having looked over dtokez code more I think what Paul suggested is a good idea but doesn't match exactly what dtokez code is doing so it is not a drop-in replacement for what dtokez  had to begin with, thus my modification of Paul's code won't work for dtokez directly either.

[Reply #11 on:]

Paul missed one:

Code:

  if(desired = 0 && hallTemp <setPoint - hysteresis)

That makes desired become zero. Better read up on the difference between = and ==.

I'll add, that's why a lot of people like to do:

Code:

  if(0 == desired && hallTemp <setPoint - hysteresis)

Because if you forget the second '=', you wind up with an assignment to a literal rather than a variable, which the compiler will catch. Thusly, completely avoiding the problem in the first place.

[Reply #12 on:]

Ok, I'm a bit lost with that one so I will leave that for now - it works so at least I can improve it later. I have now had another idea, I would like to loop the section of code that reads the pot input and updates the LCD, because at the moment the LCD will only refresh once the entire program has run - I don't need to update the temperatures that often.

I thought maybe I could use a for loop, and a counter that will loop the bit of code I just talked about through x amount of times, then run the rest of my code to the end

How would I go about doing this? I have only found examples in which a delay inside the for loop is used, or a variety that waits forever for an event before it moves on?

Thanks!

[Reply #13 on:]

Forgot to post the code that I am currently working with - it is a little cleaner now

Code:

/*
 The circuit:
 * LDR connected to analog pin 0.
 * LED / transistor connected from digital pin 3 to ground
 
 * LCD RS pin to digital pin 7
 * LCD EN pin to digital pin 8
 * LCD D4 pin to digital pin 9
 * LCD D5 pin to digital pin 10
 * LCD D6 pin to digital pin 11
 * LCD D7 pin to digital pin 12
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 * LCD LED+ (15) pin transistor
 * LCD LED- (16) to ground
 
 * Thermisor divider 1 output to analog pin 1
 * Thermisor divider 2 output to analog pin 2
 */

// These constants won't change.  They're used to give names
// to the pins used:
const int tempSelectPot = A0;      // Analog input pin that the temp select pot is attached to
const int LDRPin = A1;      // Analog input pin that the lDR is attached to
const int LCDBackLight = 3;      // Analog (PWM) output pin that the BACKLIGHT is attached to
const int coldPin = 2;      // Digital output pin that the COLD RELAY is attached to
const int frostPin = 4;      // Digital output pin that the frost warning LED is attached to
//const int hotPin = 5;      // Digital output pin that the HOT LED is attached to
const int out = A2;         // Analog input that the 'Out' thermistor is connected too
const int hall = A3;         // Analog input that the 'Hall' thermistor is connected too
const int bed = A4;         // Analog input that the 'Bed' thermistor is connected too
const int bath = A5;         // Analog input that the 'Bath' thermistor is connected too
const int lounge = A6;         // Analog input that the 'Lounge' thermistor is connected too
const int kitchen = A7;         // Analog input that the 'Kitchen' thermistor is connected too
const int modeButton = 6;      //Digital input that the mode button is connected too

//floating point values
float averageTemp = 0;         //place to store average reading
float desired = 0;         //place to store selected mode

//Parameters**************

//const int hotTemp = 20;       // upper do something threshold in degrees c
const int setPointLow = 5;    // lowest desired temp available to select in degrees c
const int setPointHigh = 25;  // highest desired temp available to select in degrees c
const int frostWarning = 5;  // outside frost warning LED on threshold in degrees c
float hysteresis = 0.4;       // Temperature error switching margin to avoid rapid activation in degrees c

const int minLight = 80;        // at or below this light level, use minimum backlight intensity
const int maxLight = 920;        // at or above this light level, use maximum backlight intensity
const int minBacklight = 10;      // lowest backlight intensity to use
const int maxBacklight = 255;    // highest backlight intensity to use

// include the library code:
#include <LiquidCrystal.h>
#include <math.h>

#define NUMSAMPLES 32 // Number of analog samples to take


double convert(double RawADC)
{
  double Temp;
  Temp = log(((10240000/RawADC) - 10000));
  Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
  Temp = Temp - 273.15;            // Convert Kelvin to Celcius

  return Temp;
}

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

int potRead = 0;         // value read from the pot
int LDRRead = 0;         // value read from the LDR
int outputValue = 0;     // value output to the PWM (analog out)
int setPoint = 0;        // value set point



void setup()
{
  lcd.begin(20, 4);
  delay(100);
 
  //Declare pin modes
  pinMode(3, OUTPUT);   //LCD BACKLIGHT
  pinMode(coldPin, OUTPUT);   //COLD WARNING
  pinMode(frostPin, OUTPUT);   //OUTSIDE FROST WARNING
  pinMode(modeButton, INPUT);   //MODE SELECT BUTTON
  digitalWrite(modeButton, HIGH); //set input button to 5v to use internal pull up
}

void loop()
{
  // LDR controlled LCD backlight via PWM part
  int sum = 0;
  for (int i=0; i<16; i++) // take 16 samples from the analog input
  {
    sum += analogRead(LDRPin);
  }
  LDRRead = sum/16; // divide by the amount of samples for the average value

  // map it to the range[0..255] of the analog output that the LCD backlight it connected to
  outputValue = LDRRead/4;   // alternative to map function for scaling down from analog input
  outputValue = map(constrain(LDRRead, minLight, maxLight), minLight, maxLight, minBacklight, maxBacklight );

  // change the analog out value to adjust LCD backlight intensity
  analogWrite(LCDBackLight, outputValue);           


  // Desired temperature selection via potentiometer part
  potRead = analogRead(tempSelectPot);
  setPoint = map (potRead, 0, 1023, setPointLow, setPointHigh);


  // Temperature measurement and averaging part
  uint8_t i;
  float average1 = 0;                     //input1
  float average2 = 0;                    //input2
  float average3 = 0;                    //input3
  float average4 = 0;                    //input4
  float average5 = 0;                    //input5
  float average6 = 0;                    //input6
  for (i=0; i< NUMSAMPLES; i++)             
  {
    average1 += analogRead(out);
    average2 += analogRead(hall);
    average3 += analogRead(bed);
    average4 += analogRead(bath);
    average5 += analogRead(lounge);
    average6 += analogRead(kitchen);
    delay(10);
  }
  average1 /= NUMSAMPLES;
  average2 /= NUMSAMPLES;
  average3 /= NUMSAMPLES;
  average4 /= NUMSAMPLES;
  average5 /= NUMSAMPLES;
  average6 /= NUMSAMPLES;

  double outTemp = convert(average1);
  double hallTemp = convert(average2);
  double bedTemp = convert(average3);
  double bathTemp = convert(average4);
  double loungeTemp = convert(average5);
  double kitchenTemp = convert(average6);

//Clear the LCD ready for fresh data to be printed
  lcd.clear();


  //THERMOSTAT DUTIES
  desired = digitalRead(modeButton);

  if(desired == HIGH && hallTemp <setPoint - hysteresis)
  {
    digitalWrite(coldPin, HIGH);   // set the LED on
    lcd.setCursor(19,4);
    lcd.print((char)165); // print symbol for local temp selection
  }
  else if (desired == HIGH && hallTemp >setPoint + hysteresis)
  {
    digitalWrite(coldPin, LOW);   // set the LED off
    lcd.setCursor(19,4);
    lcd.print((char)165);         // print symbol for local temp selection
  }
  else if (desired == LOW && averageTemp <setPoint + hysteresis)
  {
    digitalWrite(coldPin, HIGH);   // set the LED off
    lcd.setCursor(19,4);
    lcd.print((char)219);         // print symbol for average temp selection
  }
  else if (desired == LOW && averageTemp >setPoint + hysteresis){
    digitalWrite(coldPin, LOW);   // set the LED off
    lcd.setCursor(19,4);
    lcd.print((char)219);        // print symbol for average temp selection
  }


  //Print desired set point temp to LCD
  lcd.setCursor(11,4);
  lcd.print ("Set: ");

  if(setPoint <setPointLow +1)
    lcd.print((char)42);              // print symbol for frost protection setting
  else if (setPoint >setPointLow)
    lcd.print(setPoint);


  //Print average temp to LCD   
  averageTemp = hallTemp + bedTemp + bathTemp + loungeTemp + kitchenTemp;         // temp zones to take average from
  averageTemp = averageTemp/5;                                                    // divide by number of temp zones to get average

  lcd.setCursor(11,2);
  lcd.print ("Ave: ");
  lcd.print(averageTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");
   
//Print hall temp to LCD
  lcd.setCursor(0,0);
  lcd.print ("Hal: ");
  lcd.print(hallTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //Print lounge temp to LCD
  lcd.setCursor(11,0);
  lcd.print ("Lng: ");
  lcd.print(loungeTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //Print kitchen temp to LCD
  lcd.setCursor(0,1);
  lcd.print ("Kit: ");
  lcd.print(kitchenTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //Print bedroom temp to LCD
  lcd.setCursor(11,1);
  lcd.print ("Bed: ");
  lcd.print(bedTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //Print bathroom temp to LCD
  lcd.setCursor(0,2);
  lcd.print ("Bth: ");
  lcd.print(bathTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");

  //Print outside temp to LCD
  lcd.setCursor(0,4);
  lcd.print ("Out: ");
  lcd.print(outTemp, 1);
  //lcd.print((char)223);
  //lcd.print ("c");


// Exterior frost warning LED part
  if(outTemp <frostWarning - hysteresis)
    digitalWrite(frostPin, HIGH);                    // set the LED on
  else if (outTemp >frostWarning + hysteresis)
    digitalWrite(frostPin, LOW);                     // set the LED off
   
   

  delay(1000);                     
}

[Reply #14 on:]

Code:

float average1 = 0;                     //input1
  float average2 = 0;                    //input2
  float average3 = 0;                    //input3
  float average4 = 0;                    //input4
  float average5 = 0;                    //input5
  float average6 = 0;                    //input6
  for (i=0; i< NUMSAMPLES; i++)             
  {
    average1 += analogRead(out);
    average2 += analogRead(hall);
    average3 += analogRead(bed);
    average4 += analogRead(bath);
    average5 += analogRead(lounge);
    average6 += analogRead(kitchen);
    delay(10);
  }
  average1 /= NUMSAMPLES;
  average2 /= NUMSAMPLES;
  average3 /= NUMSAMPLES;
  average4 /= NUMSAMPLES;
  average5 /= NUMSAMPLES;
  average6 /= NUMSAMPLES;

  double outTemp = convert(average1);
  double hallTemp = convert(average2);
  double bedTemp = convert(average3);
  double bathTemp = convert(average4);
  double loungeTemp = convert(average5);
  double kitchenTemp = convert(average6);

This just screams "array and for loop"