Dagens projekt.

// All the code is "public domain", and free to use for everyone.
// Please mention me if you find this usefull.
//
// All kod är fri för alla att använda.
// Om du finner den användbar så nämn vart du fick den ifrån.
//
// www.coppan.se

float VERSION = 2.0;

#include <SPI.h>
#include <Ethernet.h>
#include <LiquidCrystal_I2C.h>
#include <Wire.h>

#define BLUE A1 // Blue LED
#define RED A2 // Red LED
#define HEATER_PIN A0 // Waterheater ON/OFF

#define KwH 1000 // pulses per kwh.
#define Pulse_Threshold 25000 // Min. time between pulses (ms).
#define Watt_Counter_Time 10000 // post data time (ms).
#define Watt_Time 36 // Magical number.
#define Restart_Counter 20 // Software reset after this amount of errors.

IPAddress ip(192, 168, x, x);
IPAddress gateway(192, 168, x, x);
IPAddress subnet(255, 255, 255, 0);
IPAddress dnServer(192, 168, x, x);
char server[] = "cp.se";

int Pulse = 0, Watt = 0, ErrorCounter = 0;
unsigned long LastPulse = 0UL, PulseLastTime = 0UL, WattLastTime = 0UL;

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
EthernetClient client;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup()
{
delay(2000); // Dont know.

lcd.begin();
delay(1000); // One second is an iternity.

lcd.clear();
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("Starting ");
lcd.print(VERSION);

Wire.begin();
delay(1000); // One second is an iternity.

pinMode(HEATER_PIN, INPUT);
pinMode(RED, OUTPUT);
pinMode(BLUE, OUTPUT);
digitalWrite(HEATER_PIN, LOW);

Ethernet.begin(mac, ip, dnServer, gateway, subnet);
delay(1000); // One second is an iternity.

                if (client.connect(server, 80))
		{
			client.println("GET /cp/start.php?data=1 HTTP/1.0");
                        client.println("Host: cp.se");
                        client.println("");
			delay(5);
			client.stop();
		}
		else
                {
                        lcd.setCursor(0,0);
                        lcd.print("No Network!");
                        delay(5000);
                        lcd.clear();
                        
                        ErrorCounter++;
                }

attachInterrupt(1, Blink, CHANGE); // Attach interupt #1.

lcd.clear();
}

void loop()
{
unsigned long CurrentTime = millis();

        if (CurrentTime - WattLastTime >= Watt_Counter_Time)
        {
        lcd.clear();
        lcd.backlight();
        lcd.setCursor(0,0);
        lcd.print("WATT = ");
        lcd.print(Watt * 10);
        
        lcd.setCursor(0,1);
        
        if (digitalRead(HEATER_PIN) == 0) lcd.print("Heater ON");
        else lcd.print("Heater OFF");

            WattLastTime = CurrentTime;
            Watt = (Pulse - LastPulse) * Watt_Time;
            LastPulse = Pulse;
            
            if (client.connect(server, 80))
	    {
            digitalWrite(BLUE, LOW);

            ErrorCounter = 0;
            
            client.print("GET /cp/watt.php?data=");
	    client.print(Watt);
            client.print(",");
             
                if (digitalRead(HEATER_PIN) == 0) client.print("1");
                else client.print("0");

                client.println(" HTTP/1.0");
                client.println("Host: cp.se");
                client.println("");
		delay(5);
		client.stop();
	    }
	    else
            {
                lcd.setCursor(0,1);
                lcd.print("No Network! (");
                lcd.print(Restart_Counter - ErrorCounter);
                lcd.print(")");
                
                digitalWrite(BLUE, HIGH);
                
                ErrorCounter++;                
                if (ErrorCounter >= Restart_Counter) Software_Reset();
            }           
        }
        
  	if (Pulse >= KwH)
	{
		Pulse = 0;

		if (client.connect(server, 80))
		{
                        digitalWrite(BLUE, LOW);
                        
			client.println("GET /cp/kwh.php HTTP/1.0");
                        client.println("Host: cp.se");
                        client.println("");
			delay(5);
			client.stop();
		}
		else digitalWrite(BLUE, HIGH);
        }
}

void Blink()
{
unsigned long PulseCurrentTime = micros();

  if (PulseCurrentTime - PulseLastTime >= Pulse_Threshold)
  {
            digitalWrite(RED, HIGH);
        
            PulseLastTime = PulseCurrentTime;
	    Pulse++;
  }
  else digitalWrite(RED, LOW);
}

void Software_Reset()
{
    asm volatile ("jmp 0");  
}