IMU based motion capturing

Hello,

this is my first post and I'm also very new to the whole arduino thing. What I want to do is basically this:

http://www.youtube.com/embed/_A7e3G6uok8

The closest DIY-project I found so far is this:

http://www.youtube.com/embed/0YbK41p2wIo

http://www.jpattillo.net/?page_id=72 This is the corresponding website.

At the beginning I want to focus on the motion capturing, not the feedback mechanism.

My idea for realizing an affordable motion capturing system looks like this:

http://i.imgur.com/P5eRx.jpg

In this example I would only use 3 IMU or even 2 IMU but in the future I would use at least 7 to cover the whole body. This is why I think about using an I2C multiplexer to avoid I2C adress issues.

I haven't thought much about coding, as I first want to know wether it is possible from the side of hardware.

What do you think?

Is it possible? Of course. Easy? I don't know.

My first concern would be how much information needs to be passed back and forth between the IMU and the Arduino. Can you get all the data from up to 7 IMUs as fast as you need it?

If you are using a pre-fabbed library, like FreeIMU, can it handle the I2C MUX? If not you'll have to modify or write the code. Not impossible, but maybe not trivial either.

How much processing time is needed to crunch the sensor data? Processing 7 IMUs worth of data 100 times per second might be too much for an Arduino. How fast do you need to update / log positions? For something like a golf swing, you'd want to update pretty fast, other applications might not need fast updating.

How much data needs to be sent out from the Arduino to your PC or other device? A serial link typically runs at 9600 baud, which is pretty limiting. You can run the serial link faster, use Ethernet or WiFi, but it's gonna take some time and processing power to get the data out to wherever it needs to go. I don't think this will be a limiting factor, but it is worth thinking about.

In summary, I don't think the hardware will prevent you from doing what you want, unless you need very fast updating. You may end up needing more than 1 Arduino when you get to 7 IMUs, but you can certainly get started with one and build up as you go.