Last Day! 4/3

    In class on Thursday, we added some final touches to our book and presented it to the class. I was pretty happy with the final product, though there were definitely things that I would have liked to spend more time on. I recently watched some senior MAS and CAMS theses and there was a documentary about a studio art major. She perfectly articulated something that I often feel. She said that when she is creating something she envisions making a five-course Thanksgiving dinner, but ends up making a turkey sandwich and some jello. To some extent I felt that way about our book. I wish that we had had more time to focus on the aesthetics, but it was more important that we work on the actual engineering parts, since that was the assignment and the purpose of this class. Here are some pictures that Erin took of the book:

The lights flicker when you pull Hedwig past the candles

Mrs. Noris's eyes glow!

These pictures change when the characters either put on the invisibility cloak or take the polyjuice potion

Not the best picture, but the lights are either red or green depending on whether you went to page 4 and turned off the lights or not

    The other groups' final projects were very impressive. Cailey and Maria built a circuit that lit up when you snapped your fingers or made a noise by it. Essie and Frances made a box with lights on four sides. The light on bottom of the box was the light that lit up, so different lights turned on as you rotated it. Their design was nice because the way that the battery connected to the LED was cleverly simple, like Cailey and Maria’s lantern. I should learn from them, as I tend to overcomplicate things.
    During this project I learned something that I probably should have already know about myself.  My interests lie more in applied arts than they do in engineering. Something that pains me to admit, since I was hoping I could turn my passion for making things into a stable career path. While I like to know how things work, what I really enjoy is the actual process of just making something. During the process of making the book I really wanted to visit the book arts lab in the Clapp (literally the coolest place on campus) and learn about book binding and typesetting. But I realize that this has little to do with engineering, even if it would have made our project look cooler. I am glad that I at least have a base knowledge of how circuits work, so that I can possibly implement them in future projects, and I am still interested in learning more about Arduinos and microprocessors. I am glad that I learned how to use the laser cutter, but disappointed that I still have not gotten my hands on the 3D printer.
    I will leave you with one last link! Disney has created a new device called Touché that turns any surface (even liquid!) into an interactive surface. Of course, I don’t really understand how it works, but it has something to do with capacitance sensing. The video explains that most capacitive sensing operates at one frequency, so it can only sense if the user is touching or not touching. But Touché measures capacitance over a range of frequencies, so it can tell if the user is touching, pinching, grasping or not touching. Some of the applications seem silly or far fetched, but I do like the idea of using you body to control you phone or ipod. I just wonder what happens if you make an unintentional gesture. I think Touché is definitely something to watch, I am just surprised that it did not come from Apple or Google.

Pop-up 4/30

On Monday we were working on our pop-up book when our professor hinted that our project was not a real engineering project, but only a hobby. I don't think he anticipated the frustration and name-calling that would ensue. He said that our project was not interactive enough, something that would have been nice to know earlier then project. But, to be fair, not even we had a very concrete idea of where exactly project was going. I should have known that when we chose to make a pop-up book there would be the danger of me getting distracted and wanting to make it pretty, and our professor not taking it seriously. I left class that day extremely frustrated with the fact that we had made no progress on our project, and that we didn’t even have a strong concept.
    Over the week I tried to think about what the difference between engineering and a hobby really is. The term hobby just feels very condescending. It seems kind of arbitrary to me, and I think that it might have something to do with how useful what you are making really is. But it lead me to the realization that I do not have a concrete definition of what engineering is or isn’t. Engineering stills seems like a very broad and ambiguous term.  
    However, upon reflection I realized that I was setting the wrong goals for our pop-up book. I wanted to focus on the fun and pretty parts, and add on the circuits and lights as just another level of decoration. I realized that our professor was right, and that we did need to focus on making our book more interactive. I tried to think of ways to make our project more interactive within the context of a Harry Potter themed pop-up book and arrived at the conclusion that our pop-up book needed a plot, and that it needed to be a choose your own adventure. Perhaps it is an artificial way to prompt user interaction, but I liked the idea of choices that the reader making throughout the book affecting the outcome, which was whether Harry or Malfoy won the duel in the end. Furthermore, having a plot created a context in which our circuits made more sense.
    When we met on Wednesday night to finish our book, I channeled my frustration into bossiness. Luckily, Hannah and Erin were on board with my idea, so it didn’t take too much cajoling to get Hannah to do the illustrations while Erin and I worked on the circuits.
    Erin worked on the circuit for the first page, where Hedwig flies over some candles in the great hall, causing them to flicker. We already knew how to build a circuit that made the lights flash on and off, so we just added some photocells to it so that when you covered the photocells the flashing slowed down. Photocells are resistors whose resistance decreases as the amount of light shining on it increases. So the circuit pictured below is simply an oscillator with some LEDs on the output, and a photocell by one of the resistors. We have a voltage divider on the input because even though we decided not use batteries, our circuit only used between 0 and 12v instead of -12v and +12v. Consequently, the "ground" needed to be 6.

When we built the circuit on the breadboard, when the photocell was not covered the lights flashed so quickly that it looked as if they were constant, but when you covered the photocell the lights slowed down as if they were flickering. However, when we added longer wires so that the lights and the photocells would be on the pages I think it added extra resistance, so the lights slowed down a little and did not look constant when the photocell was uncovered. I suppose we could have put a smaller resistor somewhere in the circuit, but I think the effect was still convincing enough.  Erin also built the circuit for Mrs. Noris’s eyes, which were red LEDs.
    I worked on the circuit for the last page. Initially I imagined using metal plates as switches that were either in contact or not in contact depending on whether the a paper tab on one of the pages was pushed in or pulled out. But, I couldn’t really get it to work the way I wanted, so Erin decided that we should just use switches. The circuit that we used for the switches looked like this:

The less abstract version of the circuit that Erin drew looks like this:

If both of the switches are switched one way the lights on the last page are green. If they are  both switched the other way they are red. If the switches were switched in opposite directions the lights do not turn on at all. We tried to make it so that when you pulled the tab that opened the door on the fourth page, it also moved the switches. Unfortunately, we could not figure out how to make the distance that you pull the tab to open the door the same as the distance you need to move the switches. If we had had more time this is something that I definitely would have worked on. But, we decided to write something into the story prompting the reader to turn of and LED we attached to the switches before leaving the page. It kind of felt like a cop-out, but a least it worked.
    We decided to leave the circuits on the breadboard rather than try to solder them together. Then we taped the breadboard to the bottom of a box lid, and the pop up book on the other side. If we had had more time we could have explored ways to attach the circuit without out a breadboard (possibly crimping?), and how to make the circuit work with batteries instead of the power source. But we did what we could, and I was happy with the result.

Pop-up 4/27

   On Thursday we continued working on our pop-up book. At the beginning of class we set  concrete goals for what we wanted to accomplish in an effort to be more productive in class. We decided that we wanted to have the initial circuit that we were going to put in our pop up built, and a least have a very good idea of what we wanted the illustrations to look like. I still want to make multiple pages, but I know for sure that I am getting ahead of myself. At this rate we’ll be lucky if we get one done. But at the same time, I think that if we get one page done every other page will be easier. I even have a vague idea of how to do the battery. If there’s one thing I’ve learned this year it is that I need to dial back my ambition sometimes. I usually do not have the time or skills necessary to create what I want to, and I end up disappointing myself more than anyone. The thing about Wellesley is that no one teaches us how to set achievable goals. Every ten feet there are signs that say “Women who will make a difference in the world.” Why don’t they say “women who will be employable,” or “women who will be able to pay off their student loans.” Honestly, that’s all I really want.
    So, focusing on achievable goals, we worked on our circuit. Together we tried out different values of resistors to find the ones that made our lights flash at the right frequency. Then we decided to add a potentiometer to our circuit so that the user can change the rate that the lights flash, since interactivity is a requirement of this project. I think that pop-up books by nature are interactive, but perhaps not necessarily the page that we are working on right now, so this is definitely something that we need to spend more time on. When we were looking for green LEDs, all we could find were bicolor LEDs. They were actually perfect, because they are either red or green. Our professor changed our circuit so that now our lights change between red and green. I am still pretty confused about how this works, so I will have to look at it again, and perhaps I will have a better explanation later.
    In the meantime, Hannah worked on creating illustrations. She made Harry and Voldemort figures, and we cut them out using the laser cutter. Somehow, cutting paper with the laser cutter was even cooler than cutting plastic. I hope that I never have to use scissors again. It took some experimentation to figure out the right settings for cardstock in the lasercutter. Eventually we found out that you need to use 20% power, 1.3 velocity, and 1000 for the square wave thing (...which I think is called dpi?). We also looked through the multiple pop-up books that illustrate how to make pop-up books in the engineering room and found out how to make the figures stand up.
    Over the weekend Erin and I continued working on our pop-up book. I felt like we spent a ton of time on it (and we actually were focusing!) but got nothing done. I did cut out a Hogwarts shaped background for our Harry v. Voldemort page, and I also made a hippogriff. But, there I am getting ahead of myself again. The hippogriff is for a different page, IF we ever get around to making another one. What we need to do next is decide how we will actually attach the components of our circuits together, and how we will attach them to the batteries. From our last project we learned that this will probably take a long time.
    I know this, because I am still working on our last project. The approach that I explained in my last post was working...but I am having a lot of trouble getting the coils the right height so that the batteries and and wires and everything fit within the case, but there is also enough pressure to hold the batteries in the right spot. I was also having problems with some of our wires coming unsoldered, so I had to re-solder them, and I am pretty bad soldering. The only time I’ve ever really soldered was when I was at WTP, and we made jewelry. With some luck, I got it to stick together. I didn’t realize what a pain our lantern is to put together. On a scale of 1-10 for manufacturing, I would give it a -3. But I will chalk this up to a learning experience, because I have never thought about designing something that is easy to assemble before. I always just think about making something pretty. So, we still don’t have a working lantern, or much done on our pop-up book...and we only have two days of class left. I don’t know what I am going to do. On the bright side, the weather is still kind of cold, so its not so bad spending all of time inside working on stuff.

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...

More Boxes! 3/15

On Thursday we continued working on our boxes. I focused on working on my movable joints, and trying out the living hinge.

I was completely wrong about at least one thing when it came to living hinges. I really over thought in my last post.  The material is cut all the way through instead of just part of the way. Also, the cuts are much simpler than I they look. I showed my professor the link, and he explained it to me. The cuts actually look like this:

When you bend the material they stretch and look much fancier, like this (sorry about the blurry picture):

I tried it out on a 1” square piece of plastic, and the same sized piece of wood. I spaced the cuts out 1/32” apart. The wood immediately snapped when I bent it, but the plastic actually worked out really well!

So I decided to test it out in my design. I want both of my movable joints to be at the top of my box, since it doesn’t really make sense to have a box with two whole sides that do not stay shut. A living hinge is a spring joint, so a I needed a way to hold the lid shut. Originally I planned on just having one side have a tab sticking out of it to go under the other side. But, while this made sense in my brain, my professor pointed out that there would be nothing to hold down the other side. He suggested that I put a tab on both sides to make interlocking sides. He also suggested that I put a living hinge on the tabs so that they can bend. I tested this out by making the side connected to the living hinge to the top. I left the lines 1/32‘ apart, but since my piece was 2” wide I ended up melting the plastic. So I spaced out the lines more (1/24” apart), and the piece still melted a little. Once it cooled it was fine, but it was a little warped. Next time I will space my lines 1/16” apart.

Who knew you could put so much time and thought into making a box? Do engineers make everything this complicated? When we come back from spring break we are only going to spend about another hour completing our boxes. So let me clearly and explicitly state the process I used to make this box. It feels artificial. As I wrote this it became clearer how much the steps overlap. Its a kind of hard to decide which step of the process each decision I made I made falls under.

Concept
I think that the concept was pretty much already determined for us. We simply had to build a box with 2” sides, two fixed joints, and two movable joints. All we had to do was determine specifics. I decided to make my box a cube because it seemed like the simplest, most obvious choice. Then I considered my options for the fixed sides. Because we were using a laser cutter to make our boxes, finger joints seemed like the most natural choice for the fixed sides. The only feasible options for the movable joints were contact paper and living hinges.


Decision Matrix

In my decision matrix I rated individual parts of the design rather than the design as a whole. That’s probably not the right way to do it, since engineers need to consider how their design works together as a whole, but it made the most sense in this situation because it is how I made my choices. It also seems strange that the decision matrix is before the experimentation step. I know that you should go back after your experiments and edit your matrix, but i don't know how you chose the values without any experimentation at all. It felt like the values I chose were rather arbitrary. I chose a combination of finger joints and glue as my fixed joints because I did not spend enough time testing the other options to get them right. I think that a combination of glue and finger joints is the best option for the amount of time that I have left. 

Experimentation/ Feasibility

This is the step that I probably should have spent more time on. I never really tested out anything for the fixed joints. I did observe Frances's tests with the screws and the fingering joints, and I saw that it worked really well, but I do not think it would be feasible for me to complete my box with screws because I have not spent enough time working on it. I also do not think that I have enough time to make my fingering joints fit well enough on their own. The only part that I really did experiment with was the living hinge. I know that in the future I should spend more time on this step of the design process.

I don’t think I have made it to the testing step yet, because I haven’t completed a prototype, so that’s all for now!

Boxes 3/12

    Yesterday we continued working on our boxes. Our professor recommended that we use France’s method of joining our sides using screws and cutting slots for the screws in the sides of our pieces.
    Then he showed us how to use the laser cutter on our own. Important things to remember when using the the laser cutter are:

• Save your image as an eps
• Make sure that your lines are RGB red (red 255, blue 0, green 0) and less than .003” wide
• Print your drawing from Core and set the page size to about the same size as your image
• Use the positioning tool to position your material vertically
• Refer to the numbers on the board by the laser cutter to decide what power and speed to use for  your material
• Don’t touch the laser head or crash the material into the laser

    The hardest part of using the laser cutter is that it often takes two or three passes to cut all of the way through. You have to be careful when check to see if it has cut all through not to move the material, otherwise you will loose precision. It is possible to slow down the velocity of the laser so that you can cut through the material in one pass. But you have to be careful not to slow it down too much because you risk melting the material or starting a fire.
    I had drawn my pieces in Illustrator, and I was planning on cutting some out and testing how they fit together, but then I decided to add screws to my box, so I just started over. I like new drawing better, though, because so far all four of the sides are the same. However, I am positive that this will change when I add the movable joints.
    The moveable joints are what I am most unsure about right now. He gave us a few solutions when we started building our boxes, but I didn’t really like them. One solution was to join the two sides with fingering joints, but to make the parts that stick out curved on top so that they can rotate. Then you drill a hole through the pieces and put a rod through the whole for the piece to pivot around. The problem with this is that I don’t know how to make the curved parts, and I do not want to use the drill press. He also suggested making springs by cutting very thin pieces with the laser cutter, but I think this might be difficult to achieve. Another idea was to just use contact paper for hinges, but I think there must be a better way.

(image from http://blog.makezine.com/2011/10/25/plywood-living-hinge-technique-for-laser-cutters/)   
    I googled laser cut hinges and found that one of the most popular ways to make moveable joints with a laser cutter is to use living hinges. Living hinges are places where the material can bend because lines have been cut part way through the material to make it more flexible. People have used both wood and plastic, but wood seems to be more popular for living hinges. I want to try this, but I think I will have to do a few tests to get it to work. I do not know how deep you want the cuts to be, and I do not know of a precise way to determine how deep your cut will be. I think it will be a process of trial and error. Another thing that is important to consider is where the hinge starts and where it ends. If it starts too low on the box there will be a weird gap. The boxes are so small that I do not know if there is enough space to make the hinge wide enough that the material will flex, but thin enough that the box doesn’t have a weird gap. I think that to make a living hinge you would have to cut out the piece first and then put it back in the laser cutter to cut part way through it for the hinge. I wonder if there is a more precise way to position the laser than the arrow buttons? I am not sure how sturdy these hinges will be, but I think that they will be at least as sturdy as contact paper, and more aesthetically pleasing.
    So far all of my decisions about my box have been based on research on the internet, careful thought and observations of others. Part of the reason for this is that I don’t want to waste materials.  But I know that on Thursday I really need to actually make something and test it out.
  

Boxes 3/8

Our professor asked for each of us to submit ideas for a we project we would like to work on during the week and a half before spring break, but he didn’t give us any restrictions, so we were all stumped. So, on Thursday he told us to start designing boxes. He gave us a few restrictions; our boxes had have 2” sides, and have two fixed sides and two moveable sides. Our boxes will be judged on their performance, manufacturing and aesthetic appeal. Also, it very important that we document our process as we make our boxes.
    We talked a lot about ways that we could join the sides of our boxes. We could join them with glue or screws, or a friction hold, like finger joints. We could also use a combination of some of the methods. I was thinking about ways we could join the sides, and I wondered if you can change the angle of the laser in the laser cutter to make mitered edges? I do not think I would use mitered edges, because I don’t think that they would be sturdy enough. But I do think that they would look nice.
    When I was at a summer program we built motors, and we had to build acrylic boxes to put them in. We followed a similar design process to make our motors, but we only had one shot at making everything. We couldn’t really try things, test them and go back and adjust them. My box for my motor was a disaster. It was really wonky and misshapen. We had to use a table saw to cut the sides and we put them together with screws. We drilled holes in the acrylic with the drill press, so of course my holes were terribly misaligned. Also, it took forever for me to drill the holes because I was afraid of melting the material after they had lectured us not to. So, after that experience I am ecstatic that we have the laser cutter to do the cutting for us, and that I can completely avoid using the drill press.
    When he turned us loose to start working, I was unsure of where to begin. I began googling to see how other people had made boxes using laser cutters. It turns out that there are loads of programs online where you can enter the dimensions of you box, the width of your material and the the kerf of your laser and the program will give you a vector drawing for pieces to be cut  out by your laser. There are also tutorials for methods determining the kerf of your laser cutter.
    I also found this awesome laser-cut ukulele. All of the pieces were cut out with a laser cutter, and it looks like it is mostly held together by finger joints and glue. The neck folds in the make the ukulele more portable, but I can’t tell how he accomplished that.

(Image from http://www.designboom.com/weblog/cat/8/view/17771/laser-cut-folding-ukulele-by-brian-chan.html)
    I also saw some boxes with cool designs cut into the sides. I think it would neat if you cut designs into the sides and then put an LED on the inside. But, for now I am just going to worry about building a plain box. I would like to just use fingering joints and maybe glue if needed, but I will have to play with it to get the right fit, and I will probably have to experiment with a least one other approach. I really need to think about how I will do the moveable joints.