Is it possible to mirror the contents of an SD card in a camera to the micro SD card on an Ethernet or Wireless Shield? Alternatively, is it possible to use an Arduino to access the SD card of a camera? The idea is that when the camera snaps a photo, it can be transmitted wirelessly back home. (longer distance than a eye-fi supports)
You mean concurrently accessing the SD card from the Arduino while the camera is the owner? I doubt this is possible although I'm not a SD card low level stuff specialist. BTW: in my experience an Arduino WiFi shield usually has no wider range than the Eye-Fis (depends a bit on your camera's body).
I'm open to options on mirroring the card or accessing it directly. I'm just getting my feet wet with this and my initial hair brained idea was to try and find out if I could simply add some jumper wiring from the transmit/receive on SD card of the camera to the SD card of a wireless shield. No idea if that's even possible.
Wi-fi is out as an option for wireless transmission. I'm not in a hurry to get these images, so my plan is to use xbee pro for the range and not worry about bandwidth.
I'm really trying to avoid building my own camera setup from scratch, but it may be unavoidable. Anybody know of camera kit with infrared flash that I could stuff in a weatherproof enclosure?
The SD cards I've played with are already on the end of 20 cm of cable, like these: http://arduino-info.wikispaces.com/SD-Cards
So maybe (maybe) butcher (AKA Modify) a un-needed SD card (or better a SD to MicroSD adapter) to bring out the connections you need. Then put the actual SD card outside in a small enclosure near the camera, and arrange a multiplexer chip or maybe some FET based analog switches to switch the SD card back and forth from Camera to Arduino.
Possible/probable problem: The SD card may lose it's "Initialization" when switching?
Or, maybe it's possible to "Emulate" a SD card with Arduino, and move the data to a real SD card or over wireless??
How does the Eye-Fi get it's data??
UhOh.. more questions than answers 
terryking228:
arrange a multiplexer chip or maybe some FET based analog switches to switch the SD card back and forth from Camera to Arduino.Possible/probable problem: The SD card may lose it's "Initialization" when switching?
The camera might have initialized the SD card into SD mode, your Arduino is most likely only capable of SPI mode.
Power-down-power-on the card again to reset it and re-initialize it into SPI mode
I think it would also take a decent amount of time to send a picture, in which you wouldn't be able to use the camera
maybe if it uses spi you could "listen" in and maybe have an arduino send that to an sd card, and then maybe another to send the sd card data when the first ones not busy
the benefit being they can communicate and know when to stop reading to allow one other to access