Here are some detail about using the 1/16th inch diameter clear acrylic rods to get light from a single light source to eight points around the hollow form.
Bead the end of each rod with a lighter. This forms a "frosted" bead - that is bigger than the hole the rod goes through. That took care of preventing the rods from being pulled or pushed INTO the piece. I still needed some way to keep them from being pulled or pushed OUT of the piece. Glue was out because it might disolve the acrylic. A small piece of clear shrink tubing slid on each rod from the inside - AFTER they'd been threaded through their holes solved that problem. Heating them to get them to shrink - inside the piece - took a little thinking. I thought about using a soldering iron - but since things got pretty tight inside - I was concerned about accidendtly melting something.
If you barbecue you've probably got a propane lighter type barbecue lighter - the one with the handle and trigger on one end anda LONG neck to get your hand away from where you're lighting a fire on the other end. PERFECT for shrinking shrink tubing in tight places.
Once I had the bead on one end acrylic rods in place - and kept there by their beads and shrink tubing - I could gather them together, bind them with wire and mark them for cutting to length. Once cut, some shrink tubing could be slipped over their gathered ends and shrunk to keep them there. Another piece of shrink tubing shrunk to fit the end on the gathered rods end - but left unshrunk on the bottom end gave me a place to slip in my single LED light source.
Unlike the more extroverted Younger Sister, the MIddle Sister's light couldn't be bright and flashy. I needed something subtle, yet with a range reactions to what is going on around her. An RGB LED was an obvious possibility. Unlike a single color LED, and RGB LED has three colors in one package - Red, Green and Blue. Each of the three colors can be controlled independently. By "mixing" them, you can get almost any color in the visible light spectrum. A range of emotional reactions was perfect for The Middle Sister - RED when angry - purple when moody - blue when sad - yellow when happy - green when envious - etc..
When a shadow passes over the Middle Sister's sensor the RGB LED begins scrolling through its color range, When her sensor is not shaded - her light is off - and she looks like a regular hollow form with finial. When someone or someothing gets close enough to cast a shadow on her - she changes from a regular static piece - to a dynamic interactive piece - much like the Middle Sister who inpired the piece.
Now all I needed was a program that would
a) sense a shadow
b) turn on the RGB LED
c) get it scrolling through a range of colors.
Once again, thanks to Arduino tutorials I found on the internet - there was an RGB LED program that scrollsit through its color range. With that program as a starting point, and already having the computer code for usind an LDR to sense changes in light levels and trigger something else - the program for The Middle Sister was pretty easy to put together.
Here's the "FRITZ Diagram" of the parts and what connects to what.
To see a YouTube video of this piece in action CLICK HERE