I hooked up my 3.3 Arduino Pro mini directly to the Raspberry pi, SDA to SDA, SCL to SCL, GND to GND and 3.3v to 3.3v. The arduino powers up and looks to be functional however when I run "i2cdetect -y -a 0", it does not show a connected i2c device. I'm sure my i2c is working on the RPi because I hooked a separate i2c device and the i2cdetect command finds it no problem. Do I need specific code to run on the arduino in order for it to respond to the i2cdetect command?
I've done a lot of google searching and all I can find is examples of Raspberry Pi connected via shifter/bridge to a 5v Arduino. I would be shocked if I was the only one that has ever tried connecting it to a 3.3v Arduino when it should be much simpler.