Today I etched two test boards for the pulley encoders: the RJ-45 breakout board and the emitter/detector pair board. I wanted to make sure that the board design worked correctly before ordering multiple copies of the boards. After soldering the components onto the boards, I connected a CAT-5 cable between the newly fabricated boards and the interface board I made last week. Before plugging anything in, I checked continuity on the various traces to make sure things were wired properly -- or so I thought. When I plugged in the unit after testing, I found that it didn't detect rotation. I inspected the infrared LED on the detector and found that it wasn't glowing (I used my digital camera to check). I wasn't completely surprised; when I hacked apart the mouse circuit board, I found that the X- and Y-axis LEDs were wired together. To fix this problem, I soldered the second IR LED onto the bottom of my interface board. Still no luck. Double checking things, I found that copper traces were bridged on one of the the circuit board I etched. After fixing the bridged traces, I found that the circuit still didn't work. From prior experience, I figured that either the LEDs, the phototransistors, or both were probably blown, so I decided to try again with another mouse.
Uses sound, physical performance, and the visceral tension of the Rope&Pulley instrument to explore the cycles of one man's life.
"rope&pulley" is a performance tool which combines media playback with large expressive gestures in physical space.
This afternoon I returned to Glide Design to have my pulley parts fabricated on a CNC milling machine. David Liatti tweaked my designs to make sure the mill produced the best results. The sounds of machinery running, the smell of sawdust, and the opportunity to spend the afternoon watching and learning from a man who practices the art of converting ideas into physical objects was inspiring. Thank you, David!
Yesterday as I was looking for inspiration, I found an Erhu recording from the subway platform last November. I liked that I could use my rope to "bow" the sound as I applied granular synthesis to it. I used this sample yesterday for my first drawing with the Rope&Pulley. Today, I made a larger drawing. One of the ropes controls the location of the sampling "window" (ie, the area of the sample the granular synthesis engine looks at) and the other controls the output volume. This was a fairly crude demo.
So I goofed -- maybe. When I modeled the pulleys earlier this week, I somehow messed up the dimensions. I drew the model too small -- and only caught the mistake after I purchased my materials. Remember measure twice -- cut once? Well, I didn't cut yet, but I definitely didn't measure twice.
I was not thrilled about correcting my mistake, as it will take some time to correct it. Further complicating matters is that obtaining the correct material dimensions will become more difficult, too. I will need to go to Dimension Lumber to get a custom piece milled -- and I prefer not to do that now because of the time involved. I was also somewhat concerned about the aesthetics of the pulleys, but maybe the smaller pulley looks nicer. It's going to be hard to say without seeing it build. The point of these remaining weeks is to develop my performance -- not to sweat mechanical details.
I'm going to sleep on it, consider the feedback I've received from friends, and then decide in the morning.
April 4, 2008 [tex|ges]ture - pilot G6 gel pen, graphite stick on drawing paper (54-inch x 12-inch) - 15 minute (appx.) timed drawing, video-recorded.
I did this drawing at home after returning from school on Thursday night. I'm trying to explore the transition point between the ordered, methodical, similar shape drawing and the freer, expressive, gestural drawing.
Today has been another marathon CAD session.
I created the electronic compartment cover (which is subject to change depending on the final contents). I'm waiting to hear back about milling the parts before I make any more changes. I expect that there will be some finessing to do once I build up another encoder board. Although it is tempting to start pushing towards ready-built solutions like those found at Acroname or switching over to an optical mouse encoder system, it's too late in the game to try new stuff that might not work even if it might ultimately make my life easier. I have a working system now that will serve me until the next phase of this project.
Alibre Design Xpress is powerful and pretty easy to use. One of the coolest features is the way "assemblies" work. One I sketch individual parts, there are tools for "gluing" and aligning the parts together so the form an assembly.
Unfortunately, it is also easy to get lost in the miles and miles of faces and edges. Also, it is a tool that, at least for the present. has "obsession potential" for me. I was like this with Google Sketchup, too, when I was learning it. My tendency is to become obsessed with figuring out how to do something when I run into an obstacle -- and ignore time limits I might place on my work. This is something I must avoid falling into in these final weeks, when the focii are going to be the performance, the presentation, and the paper.
Yesterday, I alternated between programming and 3-D modeling. I've assembled most of the components for the pulley supports. It has taken probably 8 hours in total to build this 3-D model. I ended up recreating the assembly this morning because some of the constraints I created on the previous assembly prevented me from moving the pieces around.
In some ways, this looks pretty similar to the mode I drew in SketchUp almost two months ago; however, this model has 3-D models of actual parts that I will purchase this week and the dimensions are exact.
I still need to create a design for the housing that covers the encoder, but that is a job for this afternoon/evening.
This is a test video of one of my first large drawings. I purchased a graphite stick at Dick Blick with the intention of making big marks. I really wanted a marker, but they only had blues and violets. I'm not so much into colors yet, so I decided to keep things simple and raw. I've made a conscious effort not to think while making these drawings. I try to allow my hand to guide the drawing and my eyes to observe so that my hand can respond to the feedback it's receiving from my eyes.