Step 6: Wire up the Arduino MEGA, Logger Shield and TelosB
Now to communicate with the real-time clock on the Logger, you have to use the Mega's hardware SDA and SCL lines but these aren't connected to the right pins on the Logger shield. You have to add a jumper from "SDA" on the Logger Shield to SDA on the Mega. Do the same thing to connect the MEGA SCL and Logger SCL pin. It's best to install a 2 pin socket on the Logger Shield rather than soldering the jumper wire directly to the logger. Note that you can't use Mega's pins 4 and 5 for other purposes, because they're already connected to SDA and SCL through the Logger Shield and any additional signals on these pins will mess up communication with the real-time clock.Now there should be 5 wires going between the TelosB, LoggerShield and Arduino MEGA:3V, 5V, tx/rx, SDA and SCL. That small orange jumper wire is there to connect up the green LED on the datalogger shield, but it's optional and probably would be smarter not to use it.