Pylon Prototype I

Design Iteration Goals

IconMech.png

The goals for the first design iteration are:

  1. Build a quick prototype to get a feel for issues
  2. Handle cabling for a Raspberry Pi B+
  3. Use only 0.75″ thick stock to simplify fabrication

The design was based on this early concept sketch:

pylonSketch

 

The design incorporates a plant motif on both the inner frame and side panels. The inner frame has a slot to accept a mounting panel for the Raspberry Pi. RTA connecting hardware is used to hold the side panels to the inner frame (a 3″ 1/4-20 threaded rods are used due to the overall length).

The overall dimensional ratios follow those discussed on the Pylon structure.

Fabrication

This prototype was fabricated in 0.75″ hardwood using a ShopBot Desktop CNC mill with a 0.25″ spiral bit (Onsrud 65-023). Tabs were used to hold the milled pieces in place after routing. Peck drilling was used to form the 0.250″ through holes for the connecting bolts. Post-CNC drilling was done to enlarge the side panel holes to accommodate the connecting nuts (3/8″ diameter).

The side panels were made from red oak and the inner frame from maple.

Pylon1CNC

 

The layout for the inner frame pieces arranged the center piece so the front is aligned with the grain. The two outer pieces have their fronts aligned against the grain.

The mounting panel for the Raspberry Pi was cut from a scrap of 0.22″ acrylic and drilled on a press.

Assembly

The inner frame was assembled with wood glue. Note that the alternating grain of the laminate stack added strength.

Pylon1GlueUp

The inner frame was stained with Red Mahogany and finished with Tung oil:

frame

 

The side panels were finished only with Tung oil.

The Raspberry Pi was mounted with nylon spacers to ensure electrical isolation. The mounting panel holes were countersunk to ensure easy fit when slid into the inner frame slot (to avoiding rubbing on the side panel).

pylon1MountPanel

 

Note that a right angle HDMI adapter was used to re-route the cable direction. Here is the unit with cables attached:

pylon1CablesInstalled

 

The set of parts for the prototype look like this (prior to attaching cables):

pylon1Parts

 

The assembled parts look like this:

pylon1

After attaching the side panels with the connecting nuts/threaded rods, the mounting panel fit was checked:

pylon1SlideInPanelpylon1PanelInstalled

With the cables attached, here is the rear view:

pylon1PanelInstalledCables

 

Here’s the assembled unit in the Living Room, next to a Craftsman style lamp:

pylon1InLivingRoom

Prototype Lessons

  1. The side might look better with a sloped mounting: pylonSlopedSides
  2. The mounting panel need a latching mechanism. Right now it just slips in and can easily fall out.

 

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