I was almost ready to give up on the huge scrub bar and use my back up prefab touch potentiometer that I got from Sparkfun. I did some more testing and ran the thing by Michael Colombo and Eric Hagan and got some good advice. The connection between the mylar layer and the ground wire wasn’t consistent enough so I had to clamp it down to get a good reading. I bought a door hinge and revered it to get the clamp.
(video documentation coming soon)
“Relationships are really hard to avoid.”
More work on the PComp final today. Went to the Container Store which was the best decision I ever made. Discovered pink ribbon which is perfect for the scrubbing bar to cover the touch sensor. Also got two nicely shaped boxes to house the screen and other electronics. Still a lot of design decisions left, like where do the headphone go, how do I mount and place the elements. Got a pretty good prototype going with cardboard which was satisfying. Still after all the work, the scrubber didn’t give me any values with Arduino. Not sure why since everything works, I can read resistance and everything, until I plug in the computer. Had to give up for tonight.
Housing for the screen.
I build this three foot slider potentiometer and it sort of works but there were a lot of design flaws. I think I should got back to my original concept of using a touch potentiometer and maybe cover the mylar with one of the cool plastic sheets from Plastic Land. My biggest stupidest flaw was using a small nail head embedded in the bottom of the slider to connect the mylar and copper. This kept getting stuck in grooves that were left from my incomplete sanding job and then tearing up the mylar. Having it be a touch potentiometer will get rid of this problem. The downside to having it be a touch potentiometer is that the user will be able to jump all over the movie, so there might be no continuity in the images if they just jump around instead of pulling across the sensor and keeping the images coming continuously. It’s possible that people will feel compelled to do this anyway, to see the story unfold in chronological time.
Last thursday I spent about 12 hours trying to make the potentiometer based on Kit of No Parts but with copper tape and mylar. I made my own illustrator file based on the design and cut it out with the laser cutter and then wired it up. Everything worked until I had it all together and then I couldn’t get a connection between the mylar and Arduino. In the example they use semi-conductive ink, which is probably what I needed. My failed attempt:
I set a few potentiometer’s to test using input with Processing and a video. I also set up Processing to work with an external monitor that I got.
I still haven’t settled on the aesthetic for the facade, but I did some sketches and pulled some images I like. I want to take a trip to Built It Green this weekend and look at that stuff.
My Processing code:
I got some copper tape in the mail on Friday, so this evening I made a potentiometer with copper tape and mylar and then I made a paper speaker. The tutorial on Kit of No Parts was helpful but not totally complete. Once I built my first version of the speaker, I realized that there were a lot of things that could improve it, so I built a speaker with a smaller coil. I was going to double it up, but didn’t get around to it. I also realized that the magnets I bought at radio shack weren’t nearly strong enough. So I took apart a dell laptop I found in the junk bin and got magnets out of the hard drive inside. This was a lot better, but I could still get much stronger magnets. I also needed more power so I got a bench power source, but then I burnt out the MOSFET transistor I was using so I had to only use about 3v of power to be safe. I got the paper speaker much louder. Still, it’s hard to imagine it will ever be loud enough to actually hear well for the purposes of the project, so I’ll probably just include headphone in the installation.
Like ICM, I talked about a couple of ideas for PCOMP final in class on Wednesday, and comments after class made me think the video project would be better to pursue. I tried to test some things today. I couldn’t get all the material I wanted, but I was able to get some mylar from Canal Plastics, which I used with a stripped wire and penny to create a potentiometer like the one on kit of no parts. I ordered some copper to make a better one and to make speakers if I have time. I used a small strip, and got pretty inconsistent values, but I was able to get a reading.
This lab went pretty quick because I had already built the transistor circuit for my stupid pet trick:
The H Bridge circuit is pretty cool. I had experimented with capacitors a bit in trying to build my amplifier circuit for the media controller, but this made things a bit more clear. As for the H Bridge, I could be wrong, but it seems like it’s just a fancy/simple way to wire something, meaning that you could achieve the same results just by using a bunch of wires. Maybe?