I want to build a trackball + spinner panel for one of my simulator games. I thought since I have a teensy lying around I could use that and make my own controller.

Both the trackball and the spinner use I2C, so I have the usual 4 cables with data, clock, VCC and ground. I should be able to connect both since the teensy 3.1 has 2 I2C interfaces, or I could connect them to the same I2C, although I am not sure which one is the address of the devices (I ripped them off a broken cabinet that was trashed).

Once I get them wired; I can set up the teensy to be a mouse device, but how do I

- Swap between devices (or have them both connected all the time, since I am using always one at time)?
- which library do I use to do the I2C conversion to mouse ? Is there a sketch already made to use I2C trackballs or spinners with the Teensy?

Thanks in advance!