I know it's not bluetooth, but have you seen http://www.eye.fi/ ?
Could I modify a camera and make it also transmit files via bluetooth using an Arduino?
Not easily. How are you going to (physically) access the SD device?Are you going to find a bluetooth module that supports file transfers or are you going to write the drivers from ground up?
The camera already has a SD card slot, so I was hoping to somehow read from it as well.
I'm looking at this bluetooth module
QuoteThe camera already has a SD card slot, so I was hoping to somehow read from it as well.Okay, well how? First you'll need physical access to it, won't you? So, start by tearing your camera apart, see where you can solder wires, and go from there.
QuoteI'm looking at this bluetooth moduleOkay well, that's a serial device. Bluetooth isn't a generic protocol. All devices conform to a profile. Serial profile doesn't support file transfers. So you'll have to write some software on the PC side to communicate with your arduino and reconstruct whatever data you send into a "file."
Then read out the file from the sd card to the arduino