Arduino Watch Build Instructions

Step 9 Soldering the Display Connector

Now that the trackball is connected and tested you can move to the display connector.  Now you do not want to directly solder to the OLED display since it uses a serial connection to communicate with the Arduino and you want to be able to upload new sketches to the Arduino after you have completed the build (only one serial connection at a time allowed). 
Use a Dremel (or other cutting tool) to cut off one of the pin slots on the Connector Housing 6 pin housing to make it a 5 pin housing.  Also you can cut down the height of the housing so that it does not stick into your wrist as much.
Take the 5 wire piece of the IDE cable from the "Parts Layout" step and crimp the wires into the female pins and insert in the housing.  To increase the strength of the connector (especially if you cut the height down) add a hot glue to where the wires come out of the housing.
Solder the other side of the wires to the Arduino as specified in the pin diagram from the "Soldering Connections Diagram" step.

At this point you can use the Arduino Watch software to test the setup.  Upload the software with the display disconnected, then disconnect the power and connect the screen.  You can then power the watch with either the battery or the FTDI.  If everything is working right you should be able to navigate the displays with the trackball and run the programs from the menu screen.  The time screens will just display 0:00 in their various formats.