Step 5Parts Layout
iImage Information

This step is where you layout the parts to see how long of wires you need to have for the watch. Remember that when the watch is on your wrist the parts will be closer together due to the curvature of the watch band. Tape the components to the watch band and see how it fits on your wrist and make sure everything is in a comfortable position. Layout the ribbon cable from the part to the Arduino and mark the distance on the cable (leaving wire to solder to), then cut the cable and strip the wires.
For the trackball to Arduino there needs to be a minimum of 7 wires (power, ground, button press, up, down, left, right). If you want to light up the trackball you can use more wires and connect to an available digital out.
For the display to Arduino there are 5 wires.