iCreate 2 with Arduino (Just getting going)

Question

I am new to the iRobot Create 2 but I do know a thing or two about the Arduino (don't assume too much though). However, in this case, I am beyond stumped over what I am sure is something simple but is somehow not obvious to me. Three people have confirmed my wiring from the Create 2 to the Arduino to be correct and the code I have looks similar to many examples that I have seen on this forum. However, I cannot get my Create 2 to do ANYTHING. I am not at all sure what is wrong and I am starting to wonder if the robot is even receiving commands let alone doing anything with them. Is there anything wrong with this code and can anybody suggest a way to verify that the robot is receiving data (since it does not beep or provide return messages)? Thank you.

EDIT (06/24 01:10 EST); Updated code (with a few notes).

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

int baudPin = 17;
int i;
int ledPin = 13;
int rxPin = 19;
int txPin = 18;

unsigned long baudTimer = 240000; // 4 minutes
unsigned long thisTimer = 0;
unsigned long prevTimer = 0;

SoftwareSerial Roomba(rxPin, txPin);

void setup() {
  pinMode(baudPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);

  // I have tired communicating with both baud rates (19200 and 115200).
  // When trying the 115200 baud, I set "i<=0;" in the loop below since
  // the pulse does not need to be sent.
  Roomba.begin(19200);
  Serial.begin(115200);
  delay(2000);

  // I hooked up an LED in series with the baudPin so that it would turn
  // off when low thus giving me some kind of visual confirmation that a
  // pulse is being sent. See additional note in loop() below.
  for (i = 1; i <= 3; i++) {
    digitalWrite(baudPin, HIGH);
    delay(100);
    digitalWrite(baudPin, LOW);
    delay(500);
    digitalWrite(baudPin, HIGH);
  }

  // I know this might not be the right way to send data to the robot,
  // but I was fiddling with this while trying to figure out a separate
  // problem regarding the TX/RX lines which I am putting off until I
  // get the baud issue straightened out.
. /*
    int sentBytes = Roomba.write("128");
    Serial.print(sentBytes);
    Serial.print("\n");
  */

  i = 0;
}

void loop() {
  thisTimer = millis();

  // The LED that I have hooked up in series with the baudPin blinks
  // when the pulse is low, thus indicating that a pulse is being sent.
  // However, it only seems to wake the robot when it is asleep. If the
  // robot is already awake when the pulse is sent, it has no affect and
  // the robot will fall asleep a minute later.
  if (thisTimer - prevTimer > baudTimer) {
    prevTimer = thisTimer;
    i = 10;
    Serial.print("Sending pulse...\n");
    digitalWrite(baudPin, LOW);
    delay(500);
    digitalWrite(baudPin, HIGH);
  }

  /*
    i++;
    Serial.print(prevTimer);
    Serial.print(" --> ");
    Serial.print(thisTimer);
    Serial.print(" --> ");
    Serial.print(i);
    Serial.print("\n");
    delay(1000);
  */
}
#########################

Answer 1

It looks like you're trying to initialize two different baud rates:

Roomba.begin(19200);
Serial.begin(115200);

So, first off I don't think it would work to have your setup using two different rates (though I may be wrong). But, more importantly, from the manual

By default, Roomba communicates at 115200 baud. If you are using a microcontroller that does not support 115200 baud, there are two ways to force Roomba to switch to 19200:

Method 1:

While powering off Roomba, continue to hold down the Clean/Power button after the light has turned off. After about 10 seconds, Roomba plays a tune of descending pitches. Roomba will communicate at 19200 baud until the processor loses battery power or the baud rate is explicitly changed by way of the OI.

Method 2:

Use the Baud Rate Change pin (pin 5 on the Mini-DIN connector) to change Roomba’s baud rate. After turning on Roomba, wait 2 seconds and then pulse the Baud Rate Change low three times. Each pulse should last between 50 and 500 milliseconds. Roomba will communicate at 19200 baud until the processor loses battery power or the baud rate is explicitly changed by way of the OI.

Did you put it in the 19200 mode? Have you tried 115200?