Smart fridge controller?

[gregcope]

Hi

Does anyone know of any code/hardware specs to replace a fridge thermostat with a smarter version that would aim to reach a lower temperature (2C) if it notices the VCC battery (input) voltage looks like it their is a charging (ie 13v) source and conversely allow the temp to rise (say to 5C) if it is on battery power whilst sailing or at anchor.

This should be quite easy with an ardunio (or clone) a temp sensor, a voltage divider/sensor on VCC and relay to mimick the actual fridge thermostat.

This is similar to the fridge mate that is no longer in production/available.

 

[GHA]

My fridge thermostat near been an arduino for some time now..
http://www.ybw.com/forums/showthread.php?393356-Isotherm-fridge-thermostat-probs
And not alone..
http://www.ybw.com/forums/showthrea...-fridge-temps-and-compressor-cycles-over-time

It now has a little display and you can programme the on/off temps over bluetooth and check if the beer is cold without getting out of your bunk.

Haven't got round to measuring voltage to do as you suggested yet but shouldn't be difficult, also it records duty cycle over the past 2 hours so another to do is raise the temperature if the duty cycle gets too high.

Not too hard, the bits are cheap off ebay. Been rock solid reliable so far.

 

[gregcope]

Ah. Fab. Got any code to share or links to hardware used?

 

[michael_w]

My Frigoboat fridge has one of their ECOnomycontrols. it consists of a small black box with the electronics and a probe that is in the fridge box. Another wire goes to the compressor.

What happens is when there are lots of volts available the compressor runs hard and is controlled by the regular thermostat. When the volts drop ie sailing or at anchor it allows the box temperature to rise to IIRC 10c and slows the compressor rate too. You can override it by pressing a button if you so wish.

I understand it was originally developed for use with eutectic plates, but is works fine with a standard evaporator too.

A brilliant bit of kit IMHO.

 

[pvb]

Ah. Fab. Got any code to share or links to hardware used?

The Isotherm Smart Energy Control does the job, I think, and works with most Danfoss compressors. About £150 in the UK. https://www.indelwebastomarine.com/int/products/cooling-technology/isotherm-smart-energy-control/

 

[GHA]

Ah. Fab. Got any code to share or links to hardware used?

Code here..

/* Thermostat to control Danfoss Fridge  */
//____________________________________________________________


/*-----( Import needed libraries )-----*/
#include <DS1307RTC.h>
#include <Time.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <Wire.h>
#include <TimeAlarms.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
//#include <SPI.h>
//#include <SD.h>  //sd card


/*---------------Setup the LCD screen-------------------------------------*/
#define I2C_ADDR    0x27 // <<----- Add your address here.  Find it from I2C Scanner
#define BACKLIGHT_PIN     3
#define En_pin  2
#define Rw_pin  1
#define Rs_pin  0
#define D4_pin  4
#define D5_pin  5
#define D6_pin  6
#define D7_pin  7


int n = 1;


LiquidCrystal_I2C  lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);




/*-----( Declare Constants )-----*/
#define ONE_WIRE_BUS 2 /*-(Connect to Pin 2 )-*/
const int compressorControlPin =  7;      // the number of the transistor pin
const int LED =  13;      // the number of the LED pin


/*-----( Declare objects )-----*/
/* Set up a oneWire instance to communicate with any OneWire device*/
OneWire ourWire(ONE_WIRE_BUS);




/* ------------Tell Dallas Temperature Library to use oneWire Library-------------- */
DallasTemperature sensors(&ourWire);


/*-----( Declare Variables )---------------------------------------------------------------*/
// Assign the addresses of your 1-Wire temp sensors.
// See the tutorial on how to obtain these addresses:
// [URL]http://www.hacktronics.com/Tutorials/arduino-1-wire-address-finder.html[/URL]


DeviceAddress Sensor01 = { 0x28, 0x57, 0xEF, 0x56, 0x05, 0x00, 0x00, 0xE4 }; 
DeviceAddress Sensor02 = { 0x28, 0xA0, 0xA4, 0x56, 0x05, 0x00, 0x00, 0x8A };             //Ambient temp
DeviceAddress Sensor03 = { 0x28, 0x99, 0x11, 0x56, 0x05, 0x00, 0x00, 0x6C };             //Cold plate
DeviceAddress Sensor04 = { 0x28, 0xDB, 0xA1, 0x46, 0x05, 0x00, 0x00, 0x00 };             //Locker
DeviceAddress Sensor05 = { 0x28, 0x27, 0xD4, 0x56, 0x05, 0x00, 0x00, 0x88 };
DeviceAddress Sensor06 = { 0x28, 0x61, 0xDE, 0x56, 0x05, 0x00, 0x00, 0xF2 };


float sensor1=0 ; float sensor2=0 ;float sensor3=0 ;float sensor4=0 ; float sensor5=0 ;float sensor6=0;
float oldSensor1=0 ; float oldSensor2=0 ;float oldSensor3=0 ;float oldSensor4=0 ; float oldSensor5=0 ;float oldSensor6=0;


int dutyCycleArray[7200];  // array to hold 2 hours of record of compressor state
int dutyCycleTotal;  


float OnTemp=5;     //temperature when comressor turns on
float OffTemp=3.5;      //temperature when compressor turns off


// set up variables using the SD utility library functions:
const int chipSelect = 10;




int compressorControlState = LOW;             // the transistor on pin 7 controlling the compressor set to off
int KeepOff=LOW;                              // inhibit flag to keep the compressor off
int LEDState=LOW;




//__________________________________________________________________________________________________________________________
//SET UP         SET UP           SET UP            SET UP
//__________________________________________________________________________________________________________________________
void setup() /*----( SETUP: RUNS ONCE )----*/
{
/*-(start serial port to see results )-*/
delay(100);
Serial.begin(9600);
Serial.println("Serial started...");


pinMode(compressorControlPin, OUTPUT);
pinMode(LED, OUTPUT);
delay(100);


/*-( Start up the DallasTemperature library )-*/
sensors.begin();


// set the resolution to 10 bit (Can be 9 to 12 bits .. lower is faster)
  sensors.setResolution(Sensor01, 10);
  sensors.setResolution(Sensor02, 10);             
  sensors.setResolution(Sensor03, 10);             
  sensors.setResolution(Sensor04, 10);
  sensors.setResolution(Sensor05, 10);
  sensors.setResolution(Sensor06, 10);
  
  //_____________________________
  // set system time to real time from rtc
  setSyncProvider(RTC.get);   // the function to get the time from the RTC and set the ststem time to this
  if(timeStatus()!= timeSet) 
     Serial.println("Unable to sync with the RTC");
  else
     Serial.println("RTC has set the system time"); 
     timeToSerial();
  
 //____________________________
//Set up LCD
lcd.begin (20,4); //  <<-----  LCD is 20 wide x 4  lines
 
lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
lcd.setBacklight(HIGH);
lcd.home (); // go home
lcd.print("LCD screen up");






  
  
 // Alarm.timerRepeat(1, Repeats); 


}/*--(end setup )---*/
//______________________________________________________________________________________________________________________________
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//______________________________________________________________________________________________________________________________










void loop()   /****** LOOP: RUNS CONSTANTLY ******/
{


delay(1000); // wait one second 




sensor1=oldSensor1; sensor2=oldSensor2; sensor3=oldSensor3; sensor4=oldSensor4; sensor5=oldSensor5; sensor6=oldSensor6;   
 // Command all devices on bus to read temperature  
  sensors.requestTemperatures();
  if (sensor1==-127) {sensor1=oldSensor1; }
  if (sensor2==-127) {sensor2=oldSensor2; }
  if (sensor3==-127) {sensor3=oldSensor3; }
  if (sensor4==-127) {sensor4=oldSensor4; }
  if (sensor5==-127) {sensor5=oldSensor5; }
  if (sensor6==-127) {sensor6=oldSensor6; }
  
  
//____________________


//turn on or off the compressor and flash the LED if running
 float tempCheck=sensors.getTempC(Sensor02);


  if (tempCheck > OnTemp) {
    if (KeepOff==LOW){
      compressorControlState = HIGH; 
    }   
    } 
  else if (tempCheck < OffTemp) {
      compressorControlState = LOW;
  }
 
   digitalWrite(compressorControlPin, compressorControlState);
   if (compressorControlState==HIGH){
      LEDState=!LEDState;
      digitalWrite(LED, LEDState);
   }
//________________________
   
  
 // read what comes in from serial and call  the menu function
   if (Serial.available() > 0) {
    int inByte = Serial.read();
    menu(inByte);  
   }
//________________________  


//Write to LCD screen
lcd.setCursor ( 0, 0 );
lcd.print("Amb Temp  =");
lcd.print(sensors.getTempC(Sensor02));


lcd.setCursor ( 0, 1 );
lcd.print("Plate Temp=");
lcd.print(sensors.getTempC(Sensor03));


lcd.setCursor ( 0, 2 );
lcd.print("Lock Temp =");
lcd.print(sensors.getTempC(Sensor04));


lcd.setCursor ( 0, 3 );
lcd.print("Comp 0n   =");
lcd.print(compressorControlState);




//------------------  Defrost ------------------------------
tmElements_t tm;
 if (RTC.read(tm)) {


int hour = tm.Hour;


if (hour==16) {
  lcd.setCursor ( 13, 3 );
  lcd.print("defrost");
  KeepOff=1;
  
   } else {
  lcd.setCursor ( 13, 3 );
  lcd.print("       ");
  KeepOff=0;
   }   
 }
//----------------Send data over bluetooth-------------------
//
Serial.print("Amb=");
Serial.println(sensors.getTempC(Sensor02));


Serial.print("plt=");
Serial.println(sensors.getTempC(Sensor03));


Serial.print("loc=");
Serial.println(sensors.getTempC(Sensor04));


  
  //TEMP____Testing_________________________TEMP______________________________TEMP


 
  
  
  //TEMP______________________________TEMP____________________________TEMP
  
  
  
  
}//--(end main loop )---
//_________________________________________________________________________________________________________________________
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//_________________________________________________________________________________________________________________________




/*-----( Declare User-written Functions )----------------------------------------------------------------------*/




void printToSerial()
{
  // Serial.print("Sensor 01 temperature is:   ");
 // printTemperature(Sensor01);
 // Serial.println();


  Serial.print("Bottom of fridge temperature is:   ");
  printTemperature(Sensor02);
  Serial.println();
 
  Serial.print("Cold plate temperature is:   ");
  printTemperature(Sensor03);
  Serial.println();
   
  Serial.print("Compressor locker ambient temperature is:   ");
  printTemperature(Sensor04);
  Serial.println();
  
  ///Serial.print("Sensor 05 temperature is:   ");
  //printTemperature(Sensor05);
  //Serial.println();
  
  //Serial.print("Sensor 06 temperature is:   ");
 // printTemperature(Sensor06);
 // Serial.println(); 
  Serial.println("********************************");


} //end printToSerial 
//________________________________________________________________________________________________________________




void printTemperature(DeviceAddress deviceAddress)
{


float tempC = sensors.getTempC(deviceAddress);


   if (tempC == -127.00) 
   {
   Serial.print("Error getting temperature  ");
   } 
   else
   {
   Serial.print(tempC);
   Serial.print("C");
   }
}// End printTemperature


//__________________________________________________________________________________________________________________________________


/*      MENU MENU               */
void menu(int inByte)
{
 switch(inByte){
   
   case 'H':
  Serial.println("Help:");
  Serial.println("Press 'S' for settings");
  Serial.println("Press 'L' for live data");
  Serial.println("Press 'T' to display time ");
  Serial.println("Press 'V' to increase turn on temp ");
  Serial.println("Press 'C' to decrease turn on temp ");
  Serial.println("Press 'X' to increase turn off temp ");
  Serial.println("Press 'Z' to decrease turn on temp ");
  Serial.println("Press '1' to keep turned off for 10 seconds ");
  Serial.println("Press '2' to keep turned off for 10 minutes ");
  Serial.println("********************************");
  break;
   
  case 'S':
  Serial.println("settings:");  
  Serial.print("Turn on compressor when temperture above ");
  Serial.println(OnTemp);
  Serial.print("Turn off compressor when temperture below ");
  Serial.println(OffTemp);
  Serial.print("Inhibit state="); 
  Serial.println(KeepOff);
  Serial.print("Compressor control state=");
  Serial.println(compressorControlState);
  Serial.println("********************************");
  break;
  
  case 'V':
  OnTemp=OnTemp+0.1;
  Serial.print("Turn on compressor when temperture reaches ");
  Serial.println(OnTemp);
  Serial.print("Turn off compressor when temperture reaches ");
  Serial.println(OffTemp);  
  Serial.println("********************************");
  break;
  
  case 'C':
  OnTemp=OnTemp-0.1;
  Serial.print("Turn on compressor when temperture reaches ");
  Serial.println(OnTemp);
  Serial.print("Turn off compressor when temperture reaches ");
  Serial.println(OffTemp);  
  Serial.println("********************************");
  break;
  
  case 'X':
  OffTemp=OffTemp+0.1;
  Serial.print("Turn on compressor when temperture reaches ");
  Serial.println(OnTemp);
  Serial.print("Turn off compressor when temperture reaches ");
  Serial.println(OffTemp);  
  Serial.println("********************************");
  break;
  
  case 'Z':
  OffTemp=OffTemp-0.1;
  Serial.print("Turn on compressor when temperture reaches ");
  Serial.println(OnTemp);
  Serial.print("Turn off compressor when temperture reaches ");
  Serial.println(OffTemp);  
  Serial.println("********************************");
  break;
  
  
  
  case 'L':
   Serial.print("Compressor is ");
  if (compressorControlState == LOW)  {
    Serial.println("not running");
  }
  else {
    Serial.println("running"); 
  }
  printToSerial();
  break;
  
  case 'T':
  compressorControlState =!compressorControlState;
  KeepOff=LOW;
  Serial.print("Compressor control state=");
  Serial.println(compressorControlState);
  Serial.print("KeepOff=");
  Serial.println(KeepOff);
  timeToSerial();


  break;
  
 case '1':
    compressorControlState=LOW;
    KeepOff=HIGH;
    Serial.println("Delay 10 sec");
    Serial.print("KeepOff=");
    Serial.print(KeepOff);
    Alarm.timerOnce(10, OnceOnly);
  break; 
  
  case '2':
    compressorControlState=LOW;
    KeepOff=HIGH;
    Serial.println("Delay 600 sec");
    Serial.print("KeepOff=");
    Serial.print(KeepOff);
    Alarm.timerOnce(600, OnceOnly);
  break; 
  
 }
}//end menu




//______________________________________________________________________________________________________________________________________




void timeToSerial(){
   tmElements_t tm;


  if (RTC.read(tm)) {
    Serial.print("Ok, Time = ");
    print2digits(tm.Hour);
    Serial.write(':');
    print2digits(tm.Minute);
    Serial.write(':');
    print2digits(tm.Second);
    Serial.print(", Date (D/M/Y) = ");
    Serial.print(tm.Day);
    Serial.write('/');
    Serial.print(tm.Month);
    Serial.write('/');
    Serial.print(tmYearToCalendar(tm.Year));
    Serial.println();
    Serial.println("********************************");
  } else {
    if (RTC.chipPresent()) {
      Serial.println("The DS1307 is stopped.  Please run the SetTime");
      Serial.println("example to initialize the time and begin running.");
      Serial.println();
    } else {
      Serial.println("DS1307 read error!  Please check the circuitry.");
      Serial.println();
    }


  }
}
//__________________________________________________________________________________________________


void print2digits(int number) {
  if (number >= 0 && number < 10) {
    Serial.write('0');
  }
  Serial.print(number);
}
//_______________________________________________________________________________________________________




void OnceOnly(){
  Serial.println("This timer only triggers once");
  KeepOff=LOW;
       
}
//_______________________________________________________________________________________________________




//*********( THE END )***********

Running on an arduino uno. The switch was just a transistor from the box of bits, sd card/real time clock board and lcd off eBay. The little board bottom left is the power supply from battery voltage down to 5v, also off ebay. All the bits are a few quid each, thermometers are DS18B20. On the code todo list is cool the fridge more if the the voltage gets above 14v and raise the on/off temperatures as the duty cycle gets high. Surprising how the duty cycle varies even just with the heat running the engine.

 

[gregcope]

Brill thanks. Just what I wanted!