Listens for incoming RF-communication about the status of my front door. The Internet Arduino sends API calls to Pushover.

FrontdoorSensorPushover.ino

#include <SPI.h>
#include <Ethernet.h>
#include <HttpClient.h>
#include <SoftwareSerial.h>

// MAC address for your Ethernet shield
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

// Pushover settings
char pushoversite[] = "api.pushover.net";
char apitoken[] = "xxxxx";
char userkey [] = "xxxxx";
int length;

int lastState = 4; //Last value that we received over RF  (0 = door closed, 1 = door open, 2 = connection lost)

long lastConnectionTime = 0;        // will store last connectioncheck
long maxTimeout = 86400000;           // max timeout for connection (24H)
int led = 9; //output and light

SoftwareSerial mySerial(2, 3); // RX, TX


EthernetClient client;
//IPAddress server(64,94,18,120);

void setup() {
  pinMode(led, OUTPUT);

  // put your setup code here, to run once:
  Serial.begin(9600);
  
  // set the data rate for the SoftwareSerial port
  mySerial.begin(9600);
  
  Serial.println("Starting receiver for Front door");
  Serial.println();

  while (Ethernet.begin(mac) != 1)
  {
    Serial.println("Error getting IP address via DHCP, trying again...");
    delay(15000);
  }
}

void loop() {
  if (mySerial.available()) {
    lastConnectionTime = millis();
    char c = mySerial.read();
    Serial.print(c);
    
    if(c == 'O' && lastState != 1) {
      lastState = 1;
    
      pushover("Frontdoor opened");  
      digitalWrite(led,LOW);
      
    } else if(c == 'C' && lastState != 0) {
      lastState = 0;
      digitalWrite(led,HIGH);

    }
   }
 
 if ((millis() - lastConnectionTime) > maxTimeout && lastState != 2) {
//We have been waiting too long, there is something wrong with the connection
//Raise alert status
      lastState = 2;
      Serial.println("Versturen: voordeur storing");
      pushover("Frontdoor error");  

  }
}


byte pushover(char *pushovermessage)
{
  String message = pushovermessage;
  Serial.println(message);

  length = 81 + message.length();

  if(client.connect(pushoversite,80))
  {
    Serial.println("connecting to Pushover...");
    
    client.println("POST /1/messages.json HTTP/1.1");
    client.println("Host: api.pushover.net");
    client.println("Connection: close\r\nContent-Type: application/x-www-form-urlencoded");
    client.print("Content-Length: ");
    client.print(length);
    client.println("\r\n");;
    client.print("token=");
    client.print(apitoken);
    client.print("&user=");
    client.print(userkey);
    client.print("&message=");
    client.print(message);
    while(client.connected())  
    {
      while(client.available())
      {
        char ch = client.read();
        Serial.write(ch);
      }
    }
    client.stop();
  }  else {
    Serial.println("connection error");
  }
}