That page states that the default baud rate is 57600bps.

What kind of development board do you have? The ADXL345 uses the I2C or SPI bus.

What does ROV mean?
Maybe you can also consider NRF24L01 modules (version with amp, not the small ones). I have a couple of those and they work very well above water, no idea how they perform underwater

Do you know how much amps the servos draw? You can use a voltage regulator to to get the voltage down to 5-6V for the servos. I wouldn't power the ultrasonic module straight from the battery, take 5V from your Uno.

The library is really good. Why not turn it into a "real" library and put it on github? These little steppers seem to be very popular, I think a lot of people could benefit from it

Yes, I have seen those IC's. They are a nice solution, but only available in a surface mount package. To difficult for me to solder myself 
Sparkfun sells this http://www.sparkfun.com/products/8745 , based on 2 BSS138 fets. It's cheap but I'm in the EU, the shipping will be more expensive then the board itself.
I've just put the 2 2N7000's and ADXL345 on a breadboard, and it works.

Ok thanks for the confirmation, I'll give it a try

How have you wired the potentiometer to the Arduino? The outer pins should be 5V and gnd, the one in the middle should go to your analog input.

I want to connect an ADXL345 accelerometer and a HMC5883L magnetometer to the 5V I2C bus of a Mega1280 based board. I've used the ADXL345 by using 4k7 resistors between the I2C pins and 3,3V in the past. It worked but I think it would be better to make a logic level converter. I found the following pdf which shows a circuit how to make this. http://www.nxp.com/documents/application_note/AN10441.pdf (see page 4) I happen to have a couple of 2N7000 N-channel mosfets. Are these suitable for this application? (datasheet: http://www.fairchildsemi.com/ds/2N/2N7000.pdf )

You forgot the most important source of all... Ebay. I just love the Chinese sellers of electronic components on ebay, have not had any bad experiences. Takes some time to get here but you get free shipping from most.

Nice to see another Rover 5 I bought one a couple of weeks ago. I've managed to write a sketch that lets me remote control it through a Nrf24L01 wireless module. I'm using the Mega1280 based Dagu red back spider controller and motor controller. Power comes from a 2 cell lipo battery.  Here's a video of mine:



I also have the version with 4 encoders/motors, but don't really have a clue what to do with the encoders  

Then you need to keep a pc running all the time. Costs electricity  ] You can buy a simple sd card reader for a couple of dollars on ebay. (I bought one from Hong Kong, for less then 4$ including shipping.) Hook that up to your Arduino and log to the sd card.

That's interesting, thanks for the info.

Ha, that works. These simple things sometime look so difficult  Thank you.

I want to use a DS1307 RTC in a home automation project to do certain time based things. I have a small DS1307 board and have managed to make it work with various sketches that I've found online. This code was very handy -> http://combustory.com/wiki/index.php/RTC1307_-_Real_Time_Clock
Now I thought lets try to make a sketch like the blink without delay example but using the data from the DS1307.
But I'm getting nowhere, I don't really have a clue how I should make this sketch... Anyone that can help me?
I've made the following sketch, which does not work.

Code:

/*
 Blink without delay using a DS1307
 Led blinks once every second.
 */

#include <Wire.h>
const int DS1307_I2C_ADDRESS = 0x68;

const int led =  13;      // the number of the light pin
int ledState = LOW;

byte second, minute, hour;

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
  return ( (val/16*10) + (val%16) );
}

void getDateDs1307()
{
  // Reset the register pointer
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.send(0x00);
  Wire.endTransmission();

  Wire.requestFrom(DS1307_I2C_ADDRESS, 3);

  second     = bcdToDec(Wire.receive() & 0x7f);
  minute     = bcdToDec(Wire.receive());
  hour       = bcdToDec(Wire.receive() & 0x3f);
}

void setup() {
  Wire.begin();
  pinMode(led, OUTPUT);     
}

void loop(){

  getDateDs1307();
  int time1 = second;

  getDateDs1307();
  int time2 = second;
  if (abs(time1 - time2) > 1)
  {
    if (ledState == LOW)
      ledState = HIGH;
    else
      ledState = LOW;

    // set the LED with the ledState of the variable:
    digitalWrite(led, ledState);
  }
}