Solar Switch for Water Heater

1// This sketch is for Arduino Uno, with a clock, an LCD screen, a mini  sloar panel, an infrared sensor and a relais
2// Solar energy is measured by a  mini solar panel attached to a window, If solar energy level exceeds a threshold  voltage then a relais switches on an electric water heater.
3// If by the end  of the daylight the duration of the water heating is insufficient,(heating < 2 hours)  then the water is further heated with main grid energy  
4// The IR sensor switches  on the light of the LCD display
5// Design by Kees Vink
6// This software is  open source.
7//Components:
8// Mini solar panel: positive on Analogue in A0
9//  clock: SCL op Analog in A5, SDA op Analog in A4, VCC op +5V
10// LCD display: like  clock (parallel to clock, both feeding and I2C)
11// Relais: S on pin 10
12//  
13//DS3231-AT24C32-IIC-High-Precision-Real-Time-Clock-Module-p-81066.html?akmClientCountry=NL&utm_design=41&utm_source=emarsys&utm_medium=Neworder171109&utm_campaign=trigger-emarsys&utm_content=winna&sc_src=email_2675773&sc_eh=5e919a3f442cad831&sc_llid=6449160&sc_lid=105229698&sc_uid=CdRKDGHiw9&cur_warehouse=CN
14//IIC-I2C-2004-204-20-x-4-Character-LCD-Display-Module-Blue-p-908616.html?utm_design=41&utm_source=emarsys&utm_medium=Neworder171109&utm_campaign=trigger-emarsys&utm_content=winna&sc_src=email_2675773&sc_eh=5e919a3f442cad831&sc_llid=6449160&sc_lid=105229698&sc_uid=CdRKDGHiw9&cur_warehouse=UK
15//UNO-R3-ATmega328P-Development-Board-For-No-Cable-p-964163.html?akmClientCountry=NL&utm_design=41&utm_source=emarsys&utm_medium=Neworder171109&utm_campaign=trigger-emarsys&utm_content=winna&sc_src=email_2675773&sc_eh=5e919a3f442cad831&sc_llid=6449160&sc_lid=105229698&sc_uid=CdRKDGHiw9&cur_warehouse=UK
16//5V-PIR-Motion-Sensor-Adjustable-Time-Delay-Sensitive-Module-p-1244536.html?akmClientCountry=NL&utm_design=41&utm_source=emarsys&utm_medium=Neworder171109&utm_campaign=trigger-emarsys&utm_content=winna&sc_src=email_2675773&sc_eh=5e919a3f442cad831&sc_llid=15735979&sc_lid=105229698&sc_uid=CdRKDGHiw9&cur_warehouse=CN
17//Portable-Mini-5V-60mA-0_3W-Solar-Epoxy-Panel-p-1144421.html?gmcCountry=NL&currency=EUR&createTmp=1&utm_source=googleshopping&utm_medium=cpc_bgcs&utm_content=frank&utm_campaign=pla-nlg-rm-all-purchase-pc&gclid=Cj0KCQiAr8bwBRD4ARIsAHa4YyK8nkgjRuT2EZHUMS5KNWzDH5LIH1HWJv7SQh2aNpPYdD7o40G5GuQaAgu1EALw_wcB&cur_warehouse=CN
18
19#include  <Wire.h>
20#include <LiquidCrystal_I2C.h>
21#define DS3231_I2C_ADDRESS 0x68
22#include  <SPI.h>
23#include <DS3231.h>  
24DS3231 Clock;
25RTClib RTC;
26byte Year;
27byte  Month;
28byte Day;
29byte DoW;
30byte Hour;
31byte Minute;
32byte Second;
33
34bool  Century=false;
35bool h12;
36bool PM;
37byte ADay, AHour, AMinute, ASecond, ABits;
38bool  ADy, A12h, Apm;
39bool Daltarief,Boiler_on,grid_time_window;
40int minontime =  300;  // minimal time (s) boiler_on before it will be turned off because of too  low solar light to avoid too many swaps (pendelen)
41long  lastswitchtime,lastIRtime;
42float  V_threshold=2.35;
43long starttime,sumtime,diftime,ontime,onLighttime;
44int pinOut  = 10;
45int nswitchtimes = 0;
46int solarpin = 0;  // pin number of solar 
47//  IR sensor:
48int sensor = 2;              // the pin that the sensor is atteched  to
49int state = LOW;             // by default, no motion detected
50int val  = 0;                 // variable to store the sensor status (value)
51
52#define  BACKLIGHT_PIN     13
53LiquidCrystal_I2C lcd(0x27, 2,1,0,4,5,6,7,3, POSITIVE);  // Set the LCD I2C address
54
55const uint8_t charBitmap[][8] = {
56   { 0xc,  0x12, 0x12, 0xc, 0, 0, 0, 0 },
57   { 0x6, 0x9, 0x9, 0x6, 0, 0, 0, 0 },
58   {  0x0, 0x6, 0x9, 0x9, 0x6, 0, 0, 0x0 },
59   { 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0, 0x0  },
60   { 0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0x0 },
61   { 0x0, 0x0, 0x6, 0x9,  0x9, 0x6, 0, 0x0 },
62   { 0x0, 0x0, 0x0, 0x6, 0x9, 0x9, 0x6, 0x0 },
63   { 0x0,  0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0x0 }
64
65};
66// Convert normal decimal numbers  to binary coded decimal
67byte decToBcd(byte val){
68  return( (val/10*16) + (val%10)  );
69}
70// Convert binary coded decimal to normal decimal numbers---------------------------------------------------------------------------------
71byte  bcdToDec(byte val){
72  return( (val/16*10) + (val%16) );
73}
74//-----------------------------------------------------------------------------------------------------------------------------------
75void  readDS3231time(byte *second,
76byte *minute,
77byte *hour,
78byte *dayOfWeek,
79byte  *dayOfMonth,
80byte *month,
81byte *year){
82  Wire.beginTransmission(DS3231_I2C_ADDRESS);
83  Wire.write(0); // set DS3231 register pointer to 00h
84  Wire.endTransmission();
85  Wire.requestFrom(DS3231_I2C_ADDRESS, 7);
86  // request seven bytes of data from  DS3231 starting from register 00h
87  *second = bcdToDec(Wire.read() & 0x7f);
88  *minute = bcdToDec(Wire.read());
89  *hour = bcdToDec(Wire.read() & 0x3f);
90  *dayOfWeek = bcdToDec(Wire.read());
91  *dayOfMonth = bcdToDec(Wire.read());
92  *month = bcdToDec(Wire.read());
93  *year = bcdToDec(Wire.read());
94}
95//-----------------------------------------------------------------------------------------------------------------------------------
96void  displayTime(){
97  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
98  // retrieve data from DS3231
99  readDS3231time(&second, &minute, &hour, &dayOfWeek,  &dayOfMonth, &month,
100  &year);
101  // send it to the serial monitor
102  lcd.setCursor  (0 ,0 );
103  lcd.print(dayOfMonth, DEC);
104  lcd.print("/");
105  lcd.print(month,  DEC);
106  lcd.print("/");
107  lcd.print(year, DEC);
108  lcd.print(" ");    
109  lcd.print(hour, DEC);
110  if (hour == 0){
111    sumtime = 0.;
112    nswitchtimes  = 0;  }  
113  // convert the byte variable to a decimal number when displayed
114  lcd.print(":");
115  if (minute<10){
116    lcd.print("0");
117  }
118  lcd.print(minute,  DEC);
119  lcd.print(":");
120  if (second<10){
121    lcd.print("0");
122  }
123  lcd.print(second, DEC);
124  lcd.setCursor (0 ,1 );  
125//  lcd.print(" Day  of week: ");
126
127  if ((hour>17) and (hour<20)) {        //opwarmen op netstroom  supplementair
128    grid_time_window=true;}
129  else{
130    grid_time_window=false;}
131  Daltarief=false;
132  if (hour>22){
133    Daltarief=true;}
134  if (hour<7){
135    Daltarief=true;}
136  //lcd.print("hour:");
137  //lcd.print(hour,DEC);
138  switch(dayOfWeek){
139  case 1:
140    lcd.print("Sunday");
141    Daltarief=true;
142    break;
143  case 2:
144    lcd.print("Monday");
145    break;
146  case 3:
147    lcd.print("Tuesday");
148    break;
149  case 4:
150    lcd.print("Wednesday");
151    break;
152  case 5:
153    lcd.print("Thursday");
154    break;
155  case  6:
156    lcd.print("Friday");
157    break;
158  case 7:
159    lcd.print("Saturday");
160    Daltarief=true;    
161    break;
162    
163  }
164}
165//-----------------------------------------------------------------------------------------------------------------------------------
166void  setup()
167{   
168  Wire.begin();
169  Serial.begin(9600);  
170  pinMode(10, OUTPUT);
171   int charBitmapSize = (sizeof(charBitmap ) / sizeof (charBitmap[0]));
172
173  // Switch on the backlight
174  pinMode ( BACKLIGHT_PIN, OUTPUT );
175  digitalWrite  ( BACKLIGHT_PIN, HIGH );
176
177  lcd.begin(19,4);               // initialize the  lcd
178  //pinMode(led, OUTPUT);      // initalize LED as an output
179  pinMode(sensor,  INPUT);    // initialize IR sensor as an input
180 
181  delay ( 1000 );
182  
183}
184//-----------------------------------------------------------------------------------------------------------------------------------
185void  loop()
186{  
187   val = digitalRead(sensor);   // read sensor value
188  if (val  == HIGH) {           // check if the sensor is HIGH
189    delay(100);                //  delay 100 milliseconds 
190    if (state == LOW) {
191      DateTime now = RTC.now();
192      lastIRtime = now.unixtime();
193      lcd.backlight();  // set lcd light on
194      state = HIGH;       // update variable state to HIGH
195    }
196  } 
197  else {
198      delay(200);             // delay 200 milliseconds 
199      
200      if (state == HIGH){
201        state = LOW;       // update variable state  to LOW
202    }
203  }
204    
205  int solarvalue = analogRead(solarpin);
206  float  solarvoltage = solarvalue*5.0/1024.0; //between 0 and 5 volts into integer values  between 0 and 1023.
207  
208  lcd.home ();                   // go home
209  lcd.clear  ();
210  displayTime(); // display the real-time clock data on the Serial Monitor  // set dal/piek en timewindow grid charge
211  lcd.setCursor ( 0, 2 );
212  if (grid_time_window)
213   { lcd.print("Tijdraam Grid");}
214  else
215    {lcd.print("Tijdraam Solar");    }
216  
217  lcd.setCursor ( 0, 3 );        // go to the next line  lcd.setCursor(col,  row)  
218  if (Daltarief){
219    lcd.print("Low  tariff");}
220  else{
221    lcd.print("Normal  tariff");  }
222  
223  delay(5000); // every second
224  lcd.home ();                   //  go home
225  lcd.clear ();
226  lcd.setCursor ( 0, 0 );        // go to the next  line  lcd.setCursor(col, row)
227  if (solarvoltage>V_threshold) 
228    lcd.print  ("Sunlight sufficient");
229  else
230    lcd.print ("Sunlight insufficient");  
231  DateTime now = RTC.now();
232  diftime = (now.unixtime()-starttime);
233  ontime = now.unixtime()-lastswitchtime;
234  onLighttime = now.unixtime()-lastIRtime;
235  if(float(onLighttime/60)>1.)  // after 1 minute light out
236    lcd.noBacklight();
237  if ((grid_time_window) and (!Boiler_on) and ((float(sumtime/3600.)<2.))){  
238    digitalWrite(pinOut, HIGH);  // switch the heater on
239    Boiler_on = true;
240    DateTime now = RTC.now();
241    starttime=now.unixtime();
242    lastswitchtime=starttime;       
243    nswitchtimes=nswitchtimes+1;
244    }
245   
246  if (!grid_time_window){
247    if((ontime>minontime) and (Boiler_on) and (solarvoltage<V_threshold)){   //  Boiler is on and will be turned off  provided it has been on for longer than minontime  (to avoid oscillation/pendelen in time of 5 min.)
248        digitalWrite(pinOut,  LOW);
249        Boiler_on = false;
250        sumtime=sumtime+diftime;
251        nswitchtimes=nswitchtimes+1;}
252    else
253      if(Boiler_on){
254        sumtime=sumtime+diftime;      
255        starttime=now.unixtime();
256        }
257    if((!Boiler_on)and(solarvoltage>=V_threshold)){   // Boiler was  off and is now set on
258      digitalWrite(pinOut, HIGH);
259      Boiler_on =  true;
260      DateTime now = RTC.now();
261      starttime=now.unixtime();
262      lastswitchtime=starttime;       
263      nswitchtimes=nswitchtimes+1;
264       }}
265  lcd.setCursor (0 ,1 );        // go to the next line     
266  if(Boiler_on)  
267    lcd.print ("Boiler aan");           
268  else
269    lcd.print ("Boiler  uit");               
270  lcd.print (" Nsw: ");
271  lcd.print (nswitchtimes);    
272  lcd.setCursor (0 ,2 );        // go to the next line        
273  lcd.print  ("Laadduur dag: ");
274  lcd.print (float(sumtime/3600.));
275  //lcd.print (sumtime);
276  lcd.print (" u");
277  lcd.setCursor (0 ,3 );        // go to the next line
278  lcd.print ("V: ");
279  lcd.print (solarvoltage);
280  lcd.print (" Vt: ");
281  lcd.print (V_threshold);
282  delay ( 5000 );
283
284}