Help with Using Multiple I2C Devices

Projects General Guidance
1

So I am part of a team trying to build a rocket to carry a 10 lb payload 10,000 ft and we would like to have a tilt sensor and a pair of barometers to measure both speed and height in order to determine when to deploy the parachute.

This is my first project using Arduino and I don't have much experience programming with sensors like this. We are using this 9DOF sensor stick

to determine whether or not the rocket has tipped over. I found some code online and slightly modified it to send a voltage to one of the pins that will set off the ejection charges. I also got two of these barometers,

The example code seems pretty straightforward and gives me the altitude based off of the pressure reading, and I can use two of these combined to create a pitot tube so I can measure velocity.

I have gotten all of these to work individually but my problem is that I do not understand at all how to connect all of these devices through I2C. I know that I have to specify the address of each device so that the Arduino can communicate with all of the sensors, but I don't know how to go about doing this. The code I am using for the 9DOF sensor stick is pretty large and I am such an amateur that I don't know which parts I can include here to help anyone, but if you would like to look at the code it can be downloaded from here,

https://dev.qu.tu-berlin.de/projects/sf-razor-9dof-ahrs/files

I am using version 1.4.1

I am also using the example code for the barometers.

Thanks for your help!

2

Is there a reason why you use the Razor code ?
It is short and fast code, but it is hard to understand how everything is organized.
You could create a file for every sensor, use the drop-down button in the right-upper corner of the Arduino IDE to add new files to your project.
In the main file, you declare the classes and call the initialization functions.

You can take a look at http://www.i2cdevlib.com/
That site uses its own I2C library, so you have to install that I2C library and the libraries for the sensors. But all libraries work well together.

The sensors you have are used a lot. But you could have bought one MPU-6050 module and two BMP085 modules on Ebay for a total of 18 dollars or 15 euros.

This is good explanation about accelerometers and gyros, Arduino Forum

3

Hi, You have more challenges than just code, but this may be a little help in combining code from different sources together:
http://arduino-info.wikispaces.com/CombiningArduinoSketches

Any feedback / suggestions on that page, from anyone, is welcome...