Task 3- Heliotropic field

The objective was to create a field of cell components that all respond and change according to the intensity and movement of the sun throughout the day and year. My group decided to use a shifting plane mechanism to move cells with the rotation of the sun. Two servos were programmed in near unison to pull, with a lever arm, the plane, which is used to maintain parallel motion of the dowels, in a parabola.  The rudimentary design process we went through can be found here, here, and here.  


How we made it work:


Allison had cut a sample planes at half the size, 6"x6", we used for the final, 12"x12", to give us the opportunity to see how the planes needed to move in relation to each other.  After determining that T-pins were an insufficient method of securing the dowels to the chipboard base, I suggested we use the sewing pins I happened to have at home.  Someone had mentioned a desire to emulate a ball joint and I realized that I had the means by which we could accomplish that very thing.

This is a close up of the pins inserted into the dowels.  The base was a layer of chipboard with very small holes laser cut into it, and glued onto a layer of foam core.  The pins pushed into the chipboard and on top of the foam created the secure, but perfectly functioning, ball joints.

To keep the top plane from slipping down the dowels we wrapped a thick wire around the dowels in a lowercase t shape. The purpose of the upper plane was to guide the dowels in a parallel manner so that the direction of each dowel was the same as all other dowels.

At first we attempted to use twine and thick rubber bands from Task 1. We found the rubber bands from our box were far to resistant to the strength of the servos we were provided.

We used smaller rubber bands as a second iteration. We determined that attaching the servos, arduino, and rubber bands to a permanent structure, or two crossed, narrow wood pieces, would provide the stability needed to maintain the integrity of the design.

The final design was attached to a wooden "x." The intent of the attached curved "petals" was to emulate what we would have liked to achieve with more time.  The reflector petals were to respond and open with the movement of the plane.  We had figured out a simple mechanism of a string attached to a stationary point (one of the planes) and the petal to pull against a spring hinge (how the petals would be affixed to the dowels) on the petal.  When the plane moved the string for the petal in the direction of the movement would tighten and pull against the spring of that petal.  Effectively opening the petal.  As the planes move to turn the petals, surrounding an LDR or solar collection device, toward a light source, the petals would open or close to focus the light on the collection device.  For presentation we made a working model of the petal open/close mechanism, a digital project filed emulating the projected behavior, and taped the petals onto the dowels in the hopes that it would hold together long enough to run the device in presentation.


I'd say it worked pretty well.



The servos were struggling a bit during the presentation and discussion. It may have been the force of the rubber bands over a much longer run time than we'd ever used in testing for functionality.

As for an analysis of group work this week- I feel like our group dynamics were great. I sincerely enjoyed working with everyone on the team.  I really appreciate the effort we made to join as many of the group members' ideas into the final product without inhibiting function and purpose.