[TL;DR] I am making an inertial motion capture system and I might need a chip with 2 separate i2c interfaces. Is there any chips like the atmega168 with 2 i2c modules, available in both PDIP and surface mount formats?
For my senior EE design project, I am making a motion capture upper-body suit using an inertial positioning system. I am planning to use accelerometers, gyroscopes and magnetometers together to achieve a usable positioning system.
There will be several triplets of Accel, Gyro and Magneto sensors, and each one of them will be connected to one (preferably cheap) avr chip. Then all those chips will be relayed together through a bus to the main cpu - a more powerful (preferably avr) chip. I was first thinking of using SPI to gather information from the sensors and then relay all the data to the main chip through i2c. However, the magnetometers I've got only support i2c and I've already reserved the i2c port for communication with the main cpu. Is there any avr chips with 2 i2c modules or should I use bit-banging / try to find an SPI compatible magnetometer? Or would you suggest a totally different approach?
[ As a side note, if anyone has done positioning with those sensors, advises are more than welcome. I don't need absolute position of the body to the ground, only the position of top limbs and inclination/twist of the body. I was thinking of using the magnetometers either as compass sensors or proximity sensors using electromagnets. As I've never used any of those sensors before, any hints would save me a lot of time and headaches. ]
All suggestions are welcome.