This may be an extremely obvious question but I don't seem able to find a definitive answer.
I have an Arduino Uno and a Sim900 GPRS/GSM shield fitted on top of it. I had I2C working on the Arduino to communicate with a Raspberry Pi, but now that I have put the shield on top I can't get the Pi to detect the Arduino. As far as I can tell the SDA and SCL pins on the Arduino aren't being used by the shield so does anyone have any idea how I go about this?
Thanks