Setting up Arduino with SMTP2GO

Step 1

/*
   Email client sketch for IDE v1.8.1 and w5100

*/

//Used Modules: Arduino Mega + W5100  Ethernet shield.

#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>


// this must be unique
byte mac[] = { 0x90, 0xA2, 0xDA, 0x00, 0x59, 0x67 };  
// change network settings to yours
IPAddress ip( 192, 168, 2, 2 );    
IPAddress gateway( 192, 168, 2, 1 );
IPAddress subnet( 255, 255, 255, 0 );

char server[] =  "mail.smtp2go.com";  
int port = 2525; // You can also try using Port Number 25, 8025 or 587.

File myFile;

EthernetClient client;

void setup()
{
  
  Serial.begin(115200);
  pinMode(4,OUTPUT);
  digitalWrite(4,HIGH);
  Ethernet.begin(mac);
  delay(2000);
  Serial.println(Ethernet.localIP());
  Serial.println(F("Ready. Press 'e' to send."));
    
}

void loop()
{
  byte inChar;

  inChar = Serial.read();
  
  if(inChar == 'e')
  {
      if(sendEmail()) Serial.println(F("Email sent"));
      else Serial.println(F("Email failed"));
  }
}

byte sendEmail()
{
  byte thisByte = 0;
  byte respCode;

  if(client.connect(server,port) == 1) {
    Serial.println(F("connected"));
  } else {
    Serial.println(F("connection failed"));
    return 0;
  }

  if(!eRcv()) return 0;

  Serial.println(F("Sending hello"));
// replace 1.2.3.4 with your Arduino's ip
  client.println("EHLO 1.2.3.4");
  if(!eRcv()) return 0;

  Serial.println(F("Sending auth login"));
  client.println("auth login");
  if(!eRcv()) return 0;

  Serial.println(F("Sending User"));
// Change to your base64 encoded user
  client.println(F("cm7zaXtrYY5kWXI=")); 
  

  if(!eRcv()) return 0;

  Serial.println(F("Sending Password"));
// change to your base64 encoded password
  client.println(F("QmlcZzJGb5Nx"));  
  

  if(!eRcv()) return 0;

// change to your email address (sender)
  Serial.println(F("Sending From"));
  client.println("MAIL From: <sender@example.com>");
  if(!eRcv()) return 0;

// change to recipient address
  Serial.println(F("Sending To"));
  client.println("RCPT To: <recipient@example.com>");
  if(!eRcv()) return 0;

  Serial.println(F("Sending DATA"));
  client.println("DATA");
  if(!eRcv()) return 0;

  Serial.println(F("Sending email"));

// change to recipient address
  client.println("To: Rachel <recipient@example.com>");

// change to your address
  client.println("From: Susan <sender@example.com>");

  client.println("Subject: Your Subject"); 

  client.println("Hi! Simple test message");

  client.println(".");

  if(!eRcv()) return 0;

  Serial.println(F("Sending QUIT"));
  client.println("QUIT");
  if(!eRcv()) return 0;

  client.stop();

  Serial.println(F("disconnected"));

  return 1;
}

byte eRcv()
{
  byte respCode;
  byte thisByte;
  int loopCount = 0;

  while(!client.available()) {
    delay(1);
    loopCount++;

    // if nothing received for 10 seconds, timeout
    if(loopCount > 10000) {
      client.stop();
      Serial.println(F("\r\nTimeout"));
      return 0;
    }
  }

  respCode = client.peek();

  while(client.available())
  {  
    thisByte = client.read();    
    Serial.write(thisByte);
  }

  if(respCode >= '4')
  {
    efail();
    return 0;  
  }

  return 1;
}


void efail()
{
  byte thisByte = 0;
  int loopCount = 0;

  client.println(F("QUIT"));

  while(!client.available()) {
    delay(1);
    loopCount++;

    // if nothing received for 10 seconds, timeout
    if(loopCount > 10000) {
      client.stop();
      Serial.println(F("\r\nTimeout"));
      return;
    }
  }

  while(client.available())
  {  
    thisByte = client.read();    
    Serial.write(thisByte);
  }

  client.stop();

  Serial.println(F("disconnected"));
}