Shelves are used to mount other components on.  So far, Leaf has three.

    The  lower shelf is used to hold the microcontroller and associated parts.  It is built by placing a 3/4" x 3/4" angle  (.055 thickness) across the front and the rear of the frame.  I then used a 6 mm thick piece of Sintra plastic to form the shelf.  6-32 screws and nuts were used to attach the angles to the frame and to attach the shelf to the angles.

   The angles and shelf were cut to a 12 3/4 inch length.  This leaves 1/2 inch in each corner to run wires up and down inside the vertical angles.

   The top shelf (on top of the frame) is a piece of aluminum attached to the frame with screws.  It is a convenient place to mount the camera microphone and speaker until I figure out something better to do for them.

   Lastly, there is another shelf mounted behind the laptop.  This shelf currently holds a USB hub and the CMPS03 compass. 

Note that there is an aluminum enclosure attached underneath each shelf which provides a nice hiding place for all the excess wire lengths of the USB cables, microphone and speaker wires and laptop recharging wire.