What’s up everyone,
It’s still early in the project and our timeline doesn’t have a due date for the display until the end of March or so, but in order to get a head start and feel for what is required in making or final volumetric display, I’ve decided to make a few proto (proto-proto-proto, I like to call them) types. I get excited when building (noob-engineering, really) new projects, so when do my first iterations I tend to hack together as quick as I can so that I can roughly see what the product will look like while getting an idea of what is necessary for making them. For example:
Yeah! Look at the perfect combination of scratched acrylic and duct tape to hastily hack together a proto-proto-proto-type! And here is a picture of me again hacking together a display source for the prism by turning my laptop upside down to get even a glimpse of what the holography would look like. I must warn you though, the results are ghastly compared to what it should really look like. I advise not to look for more than half a second.
Alas, something floating in the air, but I’m not sure what! I think this took, in total, about 3-4 hours. The hardest part was probably cutting the acrylic into the pieces I need. They come in a rectangular piece, which I have to cut (more correctly, score, then break) using a hand tool. It was hard at first because you have to know how much pressure to apply, and have to use a straight edge that is strong enough not to be cut from the hand tool. If you mess up and cut away from the straight edge, you end up scratching the f— out of your once flawless plexiglass. Again, in my excitement of finishing, I grabbed the first thing I could think of that fits this requirement – a wood saw I happened to borrow from my pops a few weeks back. It worked perfectly … after my failed attempts of trying to saw it apart first. Like I said, I always do iterations when prototyping, so the duct tape was not going to cut it (hah) for me. My next iteration involved using a caulk gun with silicone to glue the pieces together – much more sturdy while allowing for flexibility.
You can’t see it in the picture, but the job was abominable! Some sides had more silicone than others, a lot of the silicone was running rampant, eating more of the plexiglass real estate than it need to, and the silicone on the inside served little purpose other than hiding a hideous crack. This iteration did not please me as much as it should’ve. Thus, next iteration!
Yes, close to perfection! This time I used masking tape on both inner and outer sides of the prism, as well as removing excess silicone (while flattening the bond line) with a knife to make it more professional-looking. You probably can’t see it in the picture, but trust me, it looked like the prism was made using a (albeit cheap) wand! I also included a base at the bottom for added stability. With that, I completed the first prototype. The next step was to make an even bigger prototype and see how well the method I used scales. However, I didn’t use silicone because my teammates wanted something that can easily disassemble. I opted for Velcro because it’s quick, easy and offered just the right amount of sturdiness. However, it required the beauty of the plexiglass to compromise into, well … crap. In the next pictures, one of the sides of protective layers (inside) isn’t removed to prevent dust from gathering, because we aren’t going to be using this prototype quite yet. Also shown is a comparison of size to the first prototype.
If you look closely at the edges, you can see the Velcro sticking out like a sore thumb. The experience gained from the first prototype made the second suuuuch a breeze. It probably took half the time it did compared to the first one, because I knew exactly what I was doing. In the next iteration, I will probably use clear silicone (the one used with the first prototype is opaque). Another option is to use Weld-On 16 (a type of clear acrylic glue), which would, I’m guessing, give us a much better bond; however, silicone offers a bit of flexibility without falling apart so this will be something that needs to be considered in future revisions. The image relies on reflectivity of the plexiglass and in order to increase it, I tried to apply a clear gloss layer to a piece of plexiglass to see what it would look like, but it just distorts the image so that’s out of question. Finally, here is a (better) teaser of what the prism looks like (smaller prototype):
In the pictures, you can see a double reflection of the image (look at the stars, or … dots, same thing). When we talked to Robbie Tilton about this, he said his model doesn’t have this issue and it was something he’d never seen. Weird! We’ll have to look into this some more as well. Keep us with our blog to see how our project unfolds!