Pop-Up 4/23

    On Monday we finally began working on our final project. As I mentioned in my last post, we are working on a light-up-pop-up book. We decided to make our pages Harry Potter themed, since we’re all huge nerds. It also makes sense, because if pictures and paintings in the wizarding world move and talk, pop up books probably do something even cooler.
    We decided the most important thing to focus on was getting the circuit for the lights to work, and we would worry about the fun pop-up illustration parts later. Our professor said that we just needed to build an oscillator, like the one we had built earlier in the semester. So, we looked back at our notes and tried to build it, but for some mysterious reason we could not get it to work. While we were waiting for our professor to help us with our circuit we Hannah and Erin left to talk to prospies about engineering, something I don’t consider myself even remotely qualified to do. Our professor helped me with our circuit, but he actually ended up just building a new one for us. He changed it because in our original oscillator oscillated between -12 and 12 V, so the ground that we fed into V+ was zero. Since we want to use batteries to power our pop-up we only have a range of 0-5 V to work with. He put a voltage divider on our circuit to make a “ground” of 2.5 volts that went into V+. Then depending on the value of our resistors, we could change the brightness and frequency of our LEDS.
    As a group we have had problems focusing on our projects in class. We are much more productive when we work outside of class, but we wouldn’t have to work outside of class if we could just concentrate. With three of us it has been a little difficult for us to delegate the tasks so that each of us has something to be working on. I am reading Imagine by Jonah Lehrer right now, and he says that intense focus actually discourages creativity. But with only a couple days of class left what we really need to do is buckle down and get something done, especially since our last project still does not working.
    Speaking of our last project, I thought of one more way that we may be able to fix it. The problem with our lantern was that the batteries did not stay in place. I decided to alter our design slightly to split the body into a top half and a bottom half and sandwich another octagonal piece (like the top and bottom) in between them to put the top part of the battery connection on. Here is the drawing:

Then I can cut holes in the middle piece to stick wires through, so that I do not have to worry about gluing or taping them to the plastic. This also makes it easier to solder the battery connection to the circuit since the wire that I need to connect it to is on the right side. I want to make the battery connections coils like Essie and France’s. They coiled the wire in to more of a cylindrical shape than like a spiral, which is what we had tried before. My professor told me that I should also glue the piece that we had been using to hold the batteries before to the bottom and middle piece to hold the batteries in place in the other direction. So far all I have done is cut out the pieces, but I will play with this more on Thursday.

Lanterns 4/20

    We continued working on our lanterns on Friday. We were still trying to figure out how to to make the battery connections work. We tried poking holes through the plastic to keep the coils in place, and it actually worked pretty well. But when we put the whole thing back together the LEDs still did not light up. By then I was getting pretty frustrated with the whole thing. We realized that the reason our batteries were not connecting was because the part on the inside that connected to the top of the batteries kept on shifting around inside. We had put a Lego piece in earlier to prevent that from happening, but I think we abandoned it when we put the wires in because we thought that the spring from the wires would hold it in place. The problem was that our circuit was already all soldered together, so we could not really take it apart to fix the part that kept moving around. We realized that this was a major design flaw because our whole circuit was pretty much impossible to debug, since you have to put the whole thing together to make it work. Also, it’s really hard to put together and take apart. I guess this was a learning experience?
    By then class was over and we had to present our lantern to the other groups. I was pretty disappointed that we never got ours working. Maybe we were a little too ambitious?
    Cailey and Maria’s lantern was really cool. It was made out of wood, so their living hinges looked really great. I also thought that the way that they made their switch was really clever, because it was so simple. They just pushed the top part down so that the circuit connected with the batteries.
    Essie and Frances’ lantern was also really nice. They were smart, and they spent a lot of time getting the battery case right, so they were not scrambling at the last minute to get the battery connections to work. They used transparent plastic, and engraved a lightbulb on it. I thought it was very aesthetically pleasing, but Erin thought it had too many screws.
    You can find the files for making your own version of our lanterns on our class website.
    After class I thought of a possible way that we could fix our lantern, but we need to get started on our final project. So, I might have to pursue it outside of class sometime. For our final project we are planning on making some kind of thing with paper that lights up. We wanted to make a pop-up book, but we think that might be a little too ambitious. But, here is the inspiration for our final project....

Lanterns 4/19

    When we left on Thursday, all we had left was two wires to solder to complete our lantern.  At the beginning of class our professor asked us how long it would take us, and Erin said half an hour to an hour. I laughed, thinking it would take twenty minutes at most.... little did I know. One thing that I have about engineering is that is that everything takes longer than you expect it to.
    We put our pieces together only to find that our lantern did not work. So we took it apart and tested the circuit with the power that we used for our breadboard and found that while our circuit worked, the battery connections did not. We didn’t really spend a lot of time thinking about the battery connections, assuming that we could easily connect them with metal plates on the top and bottom of the batteries. The problem was that we could not get the metal plates to stay in place on the plastic, and since the opposite ends of the batteries needed to be touching the metal plate, it need to be two different heights.
    Our professor told us that Cailey and Maria had had the same problem with their lantern. I think they solved it by bending over a piece of metal so that one side was higher than the other. They also tried coiling up the wire into a spring and placing it where the battery needed to touch. We decided to try that, so we began coiling up some wires, but we were still having the same problem with attaching it to the plastic. Scotch tape just wasn’t working for us anymore! Next time we are going to try poking holes in the plastic for the wires to stick through.

Lanterns 4/12

    On Thursday we continued working on our lanterns. All we really had left to do was solder our circuit together. We also had to find a way to make our switches stay put. The holes that we cut were big enough to hold switches in place, but we were worried that you could push them through so that they would fall inside. We found some glue, but it was so thick that when we put it in the hole it scraped of of the side of the switch. We worried that we would have the same problem with hot glue, and we knew from past experience that it did not stick well to our material. We resorted to using to using clear nail polish, and although neither of us had ever used nail polish as an adhesive, it worked pretty well. Here is a diagram of the circuit, which I stole from Hannah's blog. It's nothing too complicated, its just a matter of getting it a soldered and connected to the batteries.

Here is another three dimensional view, which I also stole from Hannah's blog! I like this picture because it gives me a better idea of what it looks like. The squares at the top are the LEDs, and the rectangles on the sides with the three prongs are the switches.

Then we thought about getting the two octagonal pieces that hold our batteries to stay put. We considered using scotch tape, but we didn’t think it held well enough. So, Erin found a Lego piece that to put between the top and the one of the octagons that was the right length. Our professor said that using Legos was cheating, but I would just call it being resourceful.
    Finally, all we had left to do was solder. It was kind of a one person job, so I felt like I spent most of class looking over Hannah’s shoulder as she soldered. Luckily, Hannah is really good at soldering, way better than me at least.
    We don’t have class on Monday, so on Thursday we just have to solder a couple more wires and hope it works. In the meantime, we also have to start thinking about our final project.

Lanterns 4/9

    On Monday we continued working on our lanterns. We abandoned our pyramid design in favor of the octagonal prism idea.
    It took me a couple tries to make the top and bottom of our design the right size, and I had to review my octagonal geometry, but on the third try we got to snap right in. Actually, it fits almost too well, because it is impossible to get off.
    Then, I worked on cutting the right size of holes for the switches, while Erin worked on a piece to put on the inside to hold the batteries. She designed an octagonal piece with three holes in it for the batteries and a big hole for what Erin refers to as the “circuit junk.” She was able to cut the piece to the right size so that it floats inside the structure and holds the batteries in place. 

After a few attempts, I was also able to figure out the right size hole for the switches.

    We also debated about how we wanted the LEDs to shine through the top. We two different ways, first we cut out squares in the top the size of the whole LED. Then we tried just cutting out circles the size of the bulbs. We liked how the light looked shining through the small holes better. I think it would be cool if we put the LEDs on a octagon that floated inside, like the one one Erin made to hold the batteries. That way we could cut out swirly designs on the top for the light to shine through. Maybe if we get one done we can try out some variations.

 
    We know how we want to build our circuit from putting it together on the bread board, so now all we have to do is figure out how to solder it together.
    Our professor brought a Lytro camera to class. I know nothing about photography, but I thought it was pretty cool. I wonder if it will ever go mainstream or if they will ever find a way integrate the technology into another device, or make it smaller. I think it will be interesting to follow.
    Finally, all of the wonderful pictures in this post are Erin’s! One great thing about group work is that my partners are way better photographers than me.

Lanterns 4/5

  On Thursday we began working on our lanterns. At the beginning of class we had a brief discussion about what our lanterns needed to include before he turned us loose. We basically have to build a circuit with a LED or two in it, and a structure to contain the batteries and the circuit. We also have to have switches so that we can turn our lights on and off. Our lanterns should be as small as possible.
    We also talked about what our last project might be like. So far, all I know for sure is that it will be interactive. Our professor also showed us some clips of “useless machines,” machines whose only purpose is to turn themselves off. I know that it is weird to personify machines, but I think that useless machines are pretty great because everyone can relate to them. Or, at least I can.
    Our professor gave us some ideas about how we could structure our circuits depending on the number of LEDs we want and how we want them switch on and off. The important thing to remember is that LEDs will only work for a certain range of voltages, depending on the color of the LED.  We can use Ohm’s law to calculate what resistors we need to put in our circuit in order for our LEDs to work. The one thing that I was somewhat confused about was how we know what the current is. Our professor gave us some values, but I am not sure how he got them. He also showed us some ways that we can build our switches. He gave us one idea for a design that was actually pretty close to what I had been envisioning. He suggested that we use a living hinge to create a cylinder to enclose the circuit. I was picturing an octagonal prism with the switches on the side and the lights shining through the top.
    For this project we are working in groups. I am working with Hannah and Erin. We all had a lot of ideas about how to build our lantern. And, I think to Erin’s dismay, we even talked about the possibility of incorporating fabric or knitting into our design to help influence the direction that the light shines. Eventually we all settled on a pyramid shaped lantern with a base that is a rectangular prism that will hold the batteries and the circuit. We want our lantern to have 3 LEDs . Hannah wanted to have a red LED in our lantern so that she could use it for astronomy. Erin and I wanted to have a white LED, so we decided to use red, green and blue LEDs. That way if we shine them all together, the light might look white. Unfortunately, we could not find green LEDs, instead we will use yellow. We did find some cool bicolor LEDs that change color when you flip them. Also, we found switches, so we won’t have to engineer that aspect mechanically.
    We still have a lot to think about when it comes to our design, but I am glad that we at least have a good start!

Boxes Wrap-up 4/2

   On Monday we finished our boxes by presenting them to the class and discussing the merits of each others boxes. Before we started our professor talked to us again about the engineering design process. I must have misrepresented myself in my last post. My professor thought that I had strong objections to the engineering design process, when really I do not. I am not at all incredulous that it is important to formally write out your process, especially when when you are working with groups or designing a more complicated object. I even understand the importance of using the design process for our boxes so that we could learn how to use it. I think I was just trying to express my frustration with trying to actually write it our coherently. I was more frustrated that it was difficult to write than that I had to write it. I know that it is good practice, and the more I do it the easier it will be. I will have to watch my tone in the future posts to make sure that I am sending the right message. I am learning as much about blogging as I am about engineering in this class, and I really think that this class should count for writing 125 credit.
     After out discussion, we began evaluating each others boxes. As usual I was very impressed by my classmate’s boxes- typical Wellesley- and I was surprised by range of approaches that everyone took, and how different each person's box was. Evaluating each other’s boxes was exactly like doing a critique in a studio art class. But, instead of judging composition, tone, line and form, we were judging performance, manufacturing and aesthetic. Our ratings were pretty arbitrary, since we each had different definitions of what these categories meant. For example, Erin seemed to be judging manufacturing based upon how difficult the box was to design, whereas I judged based on the difficulty of assembling the box once it was already designed. At least in an art class there is a clear definition of what makes a dynamic balanced composition, our ratings of our boxes seemed much more subjective. 
    We started by judging Erin’s box. Her box was really cool because of the way it folded open and close, but we all agreed that aesthetically we did not like the black contact paper joining her sides. Cailey’s box looked super durable, and I really liked how it slid together and apart. Maria’s box was very aesthetically pleasing, and functional. France’s box was awesome because it was made of three pieces that were all the same, except they were each oriented differently. I was very impressed by Hannah’s ambition in making a box that was an octahedron, and her box was very pretty. I loved how hers closed with a magnet. Essie’s box was cool because she stuck with using wood, which I thought would have been too hard. Her box had lots of interesting details, and I admire her tenacity or getting the living hinge to work with wood.
    I was pretty happy with how my box turned out....except for the fact that I did not find a way to make the spring hinges stay closed. If you want to cut it out, on your own, the files are available on the class website.

  But you have to cut it out at exactly the same scale on 1/8” delrin...or else you will have to adjust some measurements, and then you’re on your own. I liked this project. I felt like I was actually engineering something. In contrast, when we were building circuits I felt like we were just plugging stuff in. But I’m sure this will come in handy, because our next project is lanterns! My fingers are still crossed that we will get to use the 3D printer....
    On a final note, I am pretty excited about this article that I read about fabric with conductive yarn that charges electronics for soldiers uniforms. I also read about it in Gizmodo, and they brought up the possibility that this technology could be available to consumers someday. I would like to learn more about textile engineering, it sounds pretty cool!

Pandora's Box 3/29

    Now that I have gotten my fixed and movable joints to work, my next challenge is to get the top of my box to stay closed. I started out by cutting out another side like the one I finished with last time. But I changed it to make it shorter so that the sides would not overlap. When I put the other side onto the box I could get each side to close individually...but I couldn’t both of them to close at once. I thought it was because one side was shorter than the other one, so one side was slightly wider on top. I thought that if I made the sides the same length both of them would close. But, my professor suggested that since I close the top the same way that joined my fixed sides. 
So I decided to try that first. I cut out two out of the four sides to test them out before I cut out the other sides. But it did not work because the top of the part that stuck out of the side was too wide. Before I had chance to modify my design and try it again I had to leave.
    Over the weekend I cajoled my friend into hanging out in the science center with me to finish my box. I was still not convinced that the method I had tried before would not work if both  sides were the same length. So I tried it, and of course I was wrong. I couldn’t get both sides to close at once. We both had to leave before I could try other ways.
    I had also begun thinking about cutting designs on the sides of my box. Maria beautified her box with some really cute little stars. Thinking about cutting designs out with a laser led me to thinking about carving pumpkins, which inevitably led to me thinking carving pumpkins with lasers. Apparently, laser cut pumpkins produce “Impressive Results and Terrible Smells.” I also thought about mimicking papel picado designs with the laser cutter. This is actually really popular for wedding invitations on Etsy. If you were feeling especially pretentious you could make a political statement by cutting out Banksy stencils on the side of your box. I stuck with simple zigzags.

I have yet to find a solution for closing my box. So it is like Pandora’s box, since it can never be closed!
    Random observations from this week: I wish that we had at least two laser cutters. It is hard to be productive in class when everyone is waiting to take their turn using it, and out class is tiny. I know this sounds pretty entitled, but we do have an ice-cream endowment. Come on Wellesley, can we have at least one more laser cutter? Also, engineering is endless frustration. But it is actually pretty rewarding when something works.

Boxes 3/26

   In last post I said that we were only going to work on boxes for part of class on Monday... but I was kidding! We actually spent all of Monday working on our boxes. But, it was a good thing, because my box needed some major tweaking.
    So, on Monday I continued with my original plan of gluing my sides together. I used hot glue, but since hot glue is so gloopy my sides did not fit together nicely. Also, I could easily peel the glue off of the plastic, so the box was not very durable. It was not an aesthetically pleasing solution either; my box was covered in those annoying little strings that you get when you use hot glue. I totally should have known this would happen; I’m no newb when it comes to using hot glue guns. 
    My plan for closing the box on top did not work either. The tabs were not bendy enough to go under the other sides, and the sides were too wide. I did not consider the eighth of an inch on each side of the top that would be taken up by the spring when I made my drawings.
    On Monday, the design process began feeling less artificial as I had to go back and change my design matrix after I experimented and tested my ideas.
    I decided that making my finger joints fit together tightly enough that I would not need glue was not such a bad idea after all! Surprisingly it was not as hard as I thought it would be, which is mostly due to luck. All I had to do was make my finger joints trapezoidal instead of rectangular shaped, so they were wider on the outer edge by 1/32” (1/64” on each side). After I modified all of my sides so that they were like this, my pieces actually snapped together pretty well.

I also had to change the top of my box so that it would close. I decided to abandon the method involving tabs in favor of my professor's suggestion. He said that I should put a tab on the side of my box, like this

I think the way this was supposed to work was that the tab would hold the top with friction, and the spring hinge would push the edge of the box up to the tab. But, it never really clicked in my mind how it was supposed to work, and after I cut out one side I did not think it would work. So I changed the side that would go opposite of it before I cut it out so that it was wider on the top, like my joints, so that it would push against the tabs and stay closed. This actually kind of worked. I could get it to stay closed, but if I set the box on a table, the side top would fly open. I guess my next step is to get the other side to close...