Clever, not smart
After one incredibly flawed — but highly informative — attempt, the Arc is working. I finished the Arc last week to present the technical findings for my Sustainable Energy class. For that class there has been less focus on the mechanical aspects of the Arc and more focus on the actual energy harnessing qualities so I am happy I get a chance to talk about what it took to construct it.
More detail photos to come!
Because my first Arc attempt went so well I decided to take another stab at it. I know exactly went wrong with the last design so I am keeping my fingers crossed that I made all the right design decisions and the construction of the Arc will go smoothly. It had better … I already dropped off all the materials and files for laser cutting at the AMS.
In the above drawing you’ll notice that there are many, many screw holes. That is because the last time I had a hard time drilling accurately into the thin masonite. The stuff would just dissolve if I made more than one pass at a hole. The fist design had no holes in the plan at all. Considering where all the screws, bolts, washers, and holes go made the drawings for this Arc a lot more complicated. I suppose if I was a lot more comfortable with a 3D rendering program this whole process would be a lot easier. Often times during the development of the drawings I would just stare at the screen for minutes at a time trying to see all the angles.
The one big change to this deign versus the last one is that there will be NO GLUING! I may use a little for reinforcement but this structure will be held together with nuts and bolts. To build up the thickness of the structure I am going to be using the material itself layered up and nylon spacers.
The one part of the old Arc that I plan on using again (with some modifications) is the base. The newly designed Arc still uses the same base design and placement of the wheels except I will have to place the two pieces of masonite closer together so that the wheels can be placed on the outside rather than in between. Additionally, rather than there being only the one larger wheel there will now be two. The one major change may be the introduction of some sort of suspension on the larger wheels. I am considering placing a spring on the axle for the larger wheels to apply some downward pressure to increase contact with the Arc. It will cause a little friction and will slow the rocking momentum a bit but I want to be sure that there is enough torque to turn the motor that is attached to the Arc via two sprockets and a chain.
I mean failure in a good way.
These are the results of my proposed midterm project.
When you look at the photos you will notice that the arc and the base are separate from one another. Well, that’s because it did not fit. It dawned on me about 3/4 of the way through the construction of the contraption that in its current design it would not and could not be assembled the way I had planned. Let me highlight the reasons why this project was destined for the scrap pile. Not really. I plan to put it somewhere in the apartment where it will stay only briefly until the fiance notices it. At which time it will end up in storage. But it will have good company. There are a handful of my sculptures already in there.
Back to the highlights.
1) I had prepared the design of the arc for laser cutting with 3/4″ masonite board as the material. I did buy 3/4″ board but it was actually slightly thinner than that. Considering there were over 100 pieces used in the construction of this piece it did not take long for the dimensions to get screwed up. Lesson learned: know your materials. Measure, measure and re-measure.
2) For whatever reason, I completely failed on the design of the base and how it would fit into the arc. Initially, I thought I caught the problem in the beginning of the construction and thought I had a solution but in the end I was still wrong. The base does not allow for the rocking movement of the arc that sits on it. And when I say “does not allow” I mean it just does not fit at all. Lesson learned: When working with multiple complex shapes consider using a 3D program to really “see” how it all fits together.
3) It’s awesome that ITP will write a grant check to you to cover the costs laser cutting at AMS. What they don’t tell you is that it is not a check to you at all but some sort of funny-money arrangement between ITP and AMS as way of paying for services. Lesson learned: Don’t assume you can simply pay out of pocket for the AMS laser cutting and go to the bank and deposit the check. The bank teller thought I was giving her a fake check.
4) Masonite is great to work with. Cuts accurately and really holds its shape. The downside is that it really can’t be overworked. Drilling, for example, really does a number on the material. One drill and one shot at setting the screw is ideal. Anything after that and the stuff starts to fall apart. And I had the good stuff! Lesson learned: Really consider the drilling into the design. The AMS laser cutter can cut some pretty tiny (and very accurate) holes in places where there needs to be a screw.
All in all I was happy with the project simply because I learned some valuable lessons. I do plan to rebuild this and really get it working for the final. Using all that I learned from this go around I think the next will be much more successful.
My midterm project is a continuation of a project I did for my Sustainable Energy class. The original inspiration of the project came from a sculpture I did quite a few years ago. I had always envisioned the sculpture as a kinetic piece but it was only until now have I started to grapple with how to make it actually function. My goal is to create a kinetic sculpture that harnesses its own kinetic energy and uses it to generate its own movement. And so this is one small step in realizing my goal.
The “Rocking Arc” project is going to be used to generate electricity that will be stored in a capacitor. The rocking movement from the arc will turn a wheel that has a sprocket and chain attached to it. The chain is connected to yet another sprocket that is attached to a 71 rpm DC motor. In my previous project for my other class, I was able to generate a fair amount of voltage but used a pendulum motion to generate it. This project is closer to my original sculpture design in that there is a rocking motion used to generate electricity.
The majority of the hardware for this project was purchased from ServoCity.com. The larger arch and housing for all of the components will be created using laser-cut masonite. (I plan to use NYU’s Advanced Media Studio for the cutting).
The assignment: Lego Lab! Pair up, build one of the simple machines out of the Lego kit (I suggest the crane). Bring your creation to class for discussion.
Scott, Adib and I decided on the the swing ride. I think it’s one of the swing rides that you might find in a carnival … or in Lego Land. It was surprisingly fun! I forgot how much I loved Legos. So much so that I would totally buy a kit. Well, let me rephrase that. If I were in a store and saw a Lego set I would totally buy it. It could potentially be a great protoyping tool. Anyway, here is what three grown men in a graduate program put together 
Here it is in all its glory! Beautiful isn’t it? Shahar, Luis and I worked for probably 10 hours total to make this thing work. Until there is a video a written explination of how it works will have to do … just use your imagination.
A lever (with a yellow hand attached) pulls a string …
Which releases a weighted Altoid tin …
That triggers a paddle …
Knocking a ping-pong ball down a tube …
That triggers a mouse trap …
Hits a rod attached to a wheel …
Spinning it to the top of the platform …
Where it knocks a weighted magnet into another tube …
aghhh , just watch the video when it’s up.
Our task
•Build a machine that cracks an egg
•Your machine should be loaded with an egg. It should be reasonably quick to reload your machine with a new egg between runs (no disassembly of the machine). Acceptable triggers to start the machine include (for example) a button press, pulling/pushing a lever, or yanking a string. Your machine should consist of at least 5 energy transfers (steps). After the initial start no human intervention is allowed. You may use any materials you can find/make/buy. Each step should be unique and contribute to the goal. Basically this means you can’t, for example, have some rolling ball hit 5 pins on its way down a ramp and have those actions count as steps (lame). The majority of the egg and NO MORE than 1/2 of the shell can end up in the final receptacle to get full credit.
