I2C LCD on Uno and Mega

Projects Networking, Protocols, and Devices
1

I am simply using the I2C Scanner:
http://playground.arduino.cc/Main/I2cScanner
to identify an LCD. The LCD is connected via a Sensor Shield V4. If I connect the Shield to an Uno, the LCD is found. If I connect it to a Mega (I have tried 2 different boards) I get: No I2C devices found
. Do I need a jumper on the mega or something. The scanner says it works for Uno and Mega, yet, I'm seeing something different. What am I doing wrong?

2

The I2C pins are different on a Mega. They are D20 and D21. That shield doesn't connect to D20 and D21. The LCD should connect to D20 and D21, not to the sensor shield.

3

Thanks. That works.