Tree structure

In this page I’m going to show the design and creation of the tree structure and lightning for the Privacy Seed project.

Structure

Sketching

During the CNC milling week I started sketching a simplified version of how the tree structure could be built: IMG_2_tree_sketch_0 IMG_2_tree_sketch_2

Here are some details of the traces carved on the tree trunk: IMG_2_tree_sketch_1

I also built a 3D model that could be built for testing on smaller scale Screenshot_2_simplified_tree

I decided to created a small scale cardboard prototype (< 1m height) and then to think about a large scale wood one (< 2m height).

First cardboard prototype (small scale)

I then decided to refine my structure to create a model to laser cut a first prototype:

Screenshot_5.1_tree_structure

Screenshot_5.2_tree_structure_for_laser_cut

I struggled a bit finding correct values for cardboard … :) :( … then I ended up with some failed cuts and these values for next time:

PowerSpeedPPI/Hz
10021000

IMG_5.3_tree_structure_prototype

By looking at this first prototype I came up with few improvements to do:

  1. In the top pressfit part: reduce the circle radius, create easier to fit shapes, make the trunk shape join precisely the circle.
  2. In the base element: create a 2 layers base and hide the trunk bottom part under it
  3. Increase the differences between the branches shapes
  4. Two possible solutions to test how to connect the heart shape: hold in one of the trunk element or hanging from top

Second plywood prototype (small scale)

Before the final presentation I built a new version of the tree structure with 3mm plywood material. This structure is ment to be a 1:5 scale of the final version.

I incorporated in the design the improvements from the first prototype and laser cut the plywood with the same settings used in week3).

Screenshot_5.9_Tree_structure_improvements

In the interest of time I cut 7 identical trunk shapes while in the previous one I had 3+4 different arrangement on the banches on each.
Also to speed up the process I thought to not include the kerf tolerance for the pressfit to have a structure that is easy to mount: Later I regretted this choice because my structure was easily falling apart :)

Here is the result:

IMG_5.10_Tree_wood_small_structure

The detail of the top circle that will support the led strip and will be covered to hide some cables.
IMG_5.11_Tree_wood_small_structure_cables_detail

The detail of the bottom plate with a slot to hold the led strip.
IMG_5.12_Tree_wood_small_structure_led_detail

The final structure all together with the heart hanging in the middle. IMG_5.13_Tree_wood_small_structure_all_together

Download models for the tree structure (.zip archive: SolidWorks, STL and Rhino files)

Wood structure (large)

Changes to incorporate:

  • LED strip lights on the trunk
  • Design a more solid base
  • Reinforce structure against vertical axis rotation
  • Think a system for easy assembly

…WORK IN PROGRESS…

Next steps

  • Design and mill a big wood structure with improvements