http://www.youtube.com/watch?v=eutFKyujC3I - talk about some wiring issues
Do we currently have any CAD drawings for v4 of the power cube? If not, I can help with this using OpenSCAD; just let me know what format I should export to, and where I should add it to the wiki (this page, or a page I haven't found yet which contains all the CADs, etc.).
In the Civilization Starter Kit v0.01 the schematics stack tolerances. In contrast, the diagrams for the Compressed Earth Brick Press (page 43) is measured from the bottom left corner. For those who are not familiar with "stacking tolerances," let me explain what this means and why it is important via an example. On page 231, the diagram in the top left: the height is 8" and the holes on the right are to be at 1" from the top and 1" from the bottom. This would better be documented as an 8" height with holes drilled at 1" from the top and 7" from the top. The reason is that cuts are never perfect, and that's okay as long as they're within tolerance (e.g. as long as they're "close enough"). However, lets say the height is only 7 and 15/16" and the bottom hole is drilled 1 and 1/16" from the bottom. Now instead of being 7" from the top, it is off by 1/8". If these same mistakes were made when taking all measurements from a reference point, it'd only be 1/16" off. Also, the reference point should not be chosen arbitrarily. It should be based on the most important point. It also may not be a corner. For example the ideal reference point on the 8"x8" plate on the right (still on page 231), it might be very important that the large hole is "perfectly" centered between the 4 smaller holes and also centered in the plate. In this case, we'd want to make the center of the 3" hole the reference point.
By the way, none of this affects the design of the cube at all. It is merely a matter of documentation. In fact, for the more advanced people who are familiar with manufacturing concepts like stacking tolerances, they can calculate and measure from a reference point, thus there's no issue at all for these people. Updating the documentation to show the measurements differently would just make it easier for new people and also reduce the risk of people making errors in calculations if they're trying to make all measurements from a reference point.
We are preparing to fabricate prototypes of Power Cube 6 - the drawings and models are being drafted right now. Would you be willing to create a wiki page about how to implement and account for tolerances when we create fabrication drawings? A brief tutorial for a draftsperson would be great - you can email me at aaron at opensourceecology.org
Just a random thought here, should we update the video header for this page, and/or move it to a different section?