Serious IMU help needed

Hi guys,
I´m looking for a little help in a project, I have been playing with IMU´s and GPS etc in order to get a system together for my RC plane that can save the attitude and GPS coords to an SD card when a signal is received from a channel on the Rc receiver for example, In various stages I have had succes reading the Attitude and saving it to the SD with a button press, I can get tiny gps to read and save GPS data to an SD with a button press, but the individual sketches are too big to simply fit all of them together on a 328 to see if they can work together,

That being said. its time to move on to the next level. I guess I am going to need a MEGA to get more sketch room.

I think its a good time in the project to ask for help with the end game plan. Which is:
read attitude and GPS data from this
and save it to an Sd card when a certain trigger event has been met, IE reached a preprogrammed waypoint.

The question is, has anyone got any tips of how to read the data our in the first place? Does anyone have any experience making something like this before ? Would anyone like to seriously help in the project ?(funds available)

I have been looking around with my first little test IMU, and found many useful sketches etc, but with this IMU im interested in doing it right from the beggining and not copy pasting peoples code.


The code to do that ought to be relatively simple. You imply that there's a problem combining both functions into a single sketch that will run on a 328. What is the problem?

The problem for now is the size of the code when using all the various libraries that are needed for the individual tests, I am going to have a go at removing unnnecesary snippets of code from both library and sketch (one at a time ) and see what happens,
But that as stated is running on my "PLAY" IMU, that gets data over IIC from the Accs. Gets GPS over SPI? from ting gps, and uses the SD library for saving to SD.

This new IMU appears to have Rs232 serial comms and TTL level serial, I assume it should be fairly straightforward to read the attitude from it, I may even be able to ahcieve that part through the trusty copy paste method. I could possible handle the SD grabbing part aswell.

The problem will come when GPS data is fused to that, and everything has to be saved quickly, I have already noticed a lag in the write time on my "PLAY IMU" when I try to save more than a few characters to SD.

I am trying to read through the various data sheets for the device to see if its nice enough to send all GPS and ATTITUDE data after a simple command is sent, maybe it wont be too hard.

The problem for now is the size of the code when using all the various libraries that are needed for the individual tests

Ah - I can see how that could be a problem. Have you listed all the libraries you're using and figured out how much each library is contributing to the the total binary sketch size, and how much program space your own code is taking up? The easy way to do that for a given library would be to comment out all the calls to it (replacing return values with dummies where necessary to get the code to compile) and see how much the binary sketch size decreased by. It's also possible to calculate the sizes from the symbol table if you prefer a less intrusive approach.

Yeah , I will have a look at size and try to reduce it, but im moving house now, and my man cave has disappeared, I have to find a new place to build more of a “man table”

My main concern now is starting to find out if I am going to be able to use the linked IMU to get more accuracy or not, as the current “TOY” is just for educational purposes,

The real goal is to get a decent IMU interfaced.

for anyone reading this,

this has a list of functions built into the IMU; it looks like it might be a straight forward thing for someone who knows more about it than me.