learning the ropes

things I made at ITP and after: sketches, prototypes, and other documentation

Thursday, February 7, 2008

rope&pulley Tests

Wendy came to ITP today to try out the rope&pulley system. We also shot some videos which better explain the interaction between the user and the system.


Here, the rope&pulley is controlling the playback speed, direction, and volume of a sample from Jimi Hendrix’s “Red House.”



posted by Michael at 11:37 pm  

Wednesday, February 6, 2008

Max Patch Revisions

Today I made some revisions to the Max/MSP patches that interface the rope&pulley to the computer. In preparation for the videotaping session I’m doing with Wendy tomorrow, I wanted to make sure that it was easy to switch back and forth between the different patches. When I’ve done that in the past, I’ve always run into trouble — I invariably forget to configure some part of the patch. While cleaning up the patches I found that I could structure things in a way that may make it easier to combine them should the need arise.

I have three different versions of the patch now:
MAX - 2008 02 06 Audio Sample Player MAX - 2008 02 06 Audio Sample Player (unlocked)
- rope&pulley controls playback direction (and optionally speed) of user-selectable .wav audio samples.

MAX - 2008 02 06 MIDI Synth Controller MAX - 2008 02 06 MIDI Synth Controller (unlocked)
- rope&pulley plays notes on a MIDI synthesizer and can adjust two user-configurable MIDI realtime controller values.

MAX - 2008 02 06 with Movie MAX - 2008 02 06 with Movie (unlocked)
- rope&pulley scrubs a looped QuickTime movieplays. Scrubbing rate is mapped to the pulley’s rotation speed and the scaling of this value can be adjusted from the patch.

posted by Michael at 5:39 pm  

Friday, January 18, 2008

User Testing

Yesterday, several people looked at my rope and pulley instrument / interface. Generally speaking, they all liked what they saw and found the interface to be intuitive. I didn’t have to really explain what to do with it — they “got it” almost immediately.

The Test Setup
- rope & pulley system connected via Arduino to computer running Max patch
- computer connected via MIDI interface to Roland M-DC-1 dance module

When my right side faces the computer, pulling the rope towards my body triggers a note on the MIDI synthesizer. Pulling the rope with increasing speed increases the volume of the note as well as a sound modulating parameter. Decreasing the pulley’s speed decreases the volume and modulation parameter. When the pulley stops rotating, the system turns off the note on the synthesizer.

I also demonstrated the original performance patch which plays Jimi Hendrix’s “Red House” when the rope is pulled.

- It was difficult for me to come up with questions on the spot to ask other than, “how did it feel?”, “was it intuitive?”, etc.

- I was hoping to observe something that would bring me an idea for the next direction, but I’m not sure if I saw something.

- I found myself explaining and demonstrating the system to generate interest in the idea even though the system was only playing a single note.
- The system needs a bit more refinement in order to demonstrate it quickly. I sometimes get flustered when I switch between modes because it doesn’t work immediately. I either need to write down the steps for setting it up or fix the Max patch so it does a few more of the setup functions automatically.

- When Amit was teaching us about user testing last year, he focused on picking a particular task. What was the task I wanted tested? It was hard to get specific answers because I wasn’t asking specific questions.

- The responsiveness of the system is an important feature. Right now it feels good.

- All testers found that synthesizer version of the system really needed something to happen when the string was pulled back in the direction of the sensing wheel. It wasn’t clear what that something should be, though. Shinyoung suggested some sort of record scratching sound. Rui understood the technical problem I was having with mapping volume / modulation with a positive and negative motion source. But he agreed that it felt strange that nothing happened in the “negative” direction. For this reason, he found that he liked the interaction with the computer-based sample playback (“Red House”) better. The sample playback corresponded directly to the motion he was making with the rope. As he pulled the rope towards his body, the sample played “forward”, slowing down and speeding up as he pulled with varying speeds. When he pulled the rope in the opposite direction, the sample responded in kind.

- One of the testers was very much interested in the body motion available as a result of this system. Being a “non-musical person”, she was interested in how someone moves when playing the instrument. She wanted to see the installation of this instrument afford a nice set of gestures / body movements for the user. To observe this sort of behavior, I think I may need to build another unit that can easily be mounted horizontally, vertically (or on any angle, for that matter).

- Another tester enjoyed the materials the system was made out of. He felt like he could be rough and expressive with it because it was made out of discarded materials. Because the interface was not “precious,” he felt that he could play hard. He mentioned that he wouldn’t feel bad breaking the string or some other part of the mechanism because he had the sense that things would be easy to fix. If I can get the knot right, this would probably be the case. The only things I really worry about in the system as it is (made out of cardboard), is a kid trying to hang off of the rope. What I’ve observed several times is that people playing with an interface for the first time want to play ROUGH as the developer looks on in horror.

- I want the ability to change pitches on the instrument — but not with the pulley. I want some sort of system on the floor that allows discrete pitch selection. One of the testers agreed with this.

- There may be something important about the fact that you can hide behind this instrument (like a guitar, piano, or even a laptop)

- I am hesitant to provide speed control over the sample playback unless it has some very natural smoothing that doesn’t allow it to get too much out of control. These could be done as a series of short user feedback experiments. The other trick in allowing speed control is that stopping the rope must instantly stop the sound. This is one of the affordances of the current system. This could change if I add more mass to the pulley, however. A metal pulley will definitely want to keep spinning unless the rope is heavy enough (and has enough friction) to stop it.

- It was suggested that I ask other people (non sound people) should try it out and see if they get the mapping

- Jamie suggested trying a collaboration with motion theater people (like Judson Church) to establish a type of choreography.

posted by Michael at 11:43 am  

Monday, January 7, 2008

Tiny Surveillance Camera Housing

Wendy is worried about the tiny surveillance cameras. She wants some way to position them safely. After brainstorming, we realize that a tripod might be the quickest way to get up and running — the lowest barrier to getting to the next step. I will mount the cameras in small protective enclosures.


1/4″-20 turns out to be a very important specification for photography. This is the dimension of the bolt found on camera tripods.

IMG_9041 IMG_9042 IMG_9043 IMG_9044 IMG_9045 IMG_9046 IMG_9047 IMG_9048 IMG_9049 IMG_9051 IMG_9052 IMG_9053 IMG_9054 IMG_9055 IMG_9056 IMG_9058 IMG_9059 IMG_9060 IMG_9061 IMG_9066 IMG_9068

posted by Michael at 12:34 am  

Wednesday, December 19, 2007


On December 13th, I played moneytone as part of the NIME/Algorithmic Composition show at ExitArt. The 6 minute long composition was my final project for Algorithmic Composition, taught by R. Luke Dubois.

The composition was driven by financial transaction data from the past seven years of my life. I’ve been tracking my spending and earnings using software programs since 1998 and wanted to hear what this fairly large dataset (comprising 3143 days) could sound like.

moneytone patch performance

Instead of simply playing a recording of the piece, I chose to perform it live to see if it would be more engaging as a performance. I built some realtime interaction into the Max/Msp patch I was using to sonify the data so I could adjust the intensity of each of the 54 category frequency bands in the piece.

posted by Michael at 2:40 pm  

Wednesday, December 19, 2007

Other Ropes & Pulleys

I saw this video yesterday while surfing Bj√∂rk’s website. It’s ironic. Several weeks ago, Jamie Allen suggested I check out Michel Gondry as a reference for my cardboard work. It turns out that Gondry works with rope and pulleys, too.

Here’s the original Michel Gondry reference. The Science of Sleep

posted by Michael at 10:28 am  

Monday, December 10, 2007

Rope & Pulley Performance Test

Excerpt from a short videorecording I made to see what I looked like performing the Rope & Pulley. I’ve been working on the Christmas Carol all week and am not sure what I’m going to be able to present in class tomorrow night. This is a return to the original thinking behind the project, but at least I will be able to present something if it is entertaining.

In the video, the system is controlling the volume of audio playback. If I were to stop pulling the rope through my hands, the track would stop playing and the volume would decrease.

posted by Michael at 1:02 pm  

Friday, December 7, 2007

Finishing Touches

No, it’s not an electric prod for a miniature cow… it’s a work around for a vexing problem: how do I keep the optical encoder wheel securely attached to the shaft. Neither Elmer’s white glue nor hot glue were keeping the part attached to the paper sleeve, so I turned to one of my other favorite building materials: wire. I created two wire prongs to put pressure on the encoder wheel so it would stay in place.

IMG_8817 IMG_8818 IMG_8820 IMG_8821

Another challenge — I was a bit careless when I cut out a few of the layers for the pulley housing. As a result, it doesn’t sit flat and it causes the shaft to bind up when the assembly is clamped down. After struggling with the thought of completely rebuilding, I realized that I could make a flexible joint to allow some play in the mechanism. Thank you, hot glue!

IMG_8822 IMG_8824 IMG_8826

posted by Michael at 1:56 pm  

Thursday, December 6, 2007

Building it Out

Pulley Support Redesign and Construction-0

It’s time to step away from the prototype and move towards a finished-looking product. Since I’ve also discovered that driving the mouse ball from the outer rim of my pulley causes the ball to spin too fast, I’ve decided to track the rotation at the shaft instead. This means I need the shaft to be attached to the pulley rather than spinning freely through its center.

I built another model in sketchup to understand how the pieces were going to fit together (and also to beef up my sketchup chops — bad idea, but I have a nice illustration now). [ later realization: one thing that's important to remember about these exercises is to continually question major time investments --at their outset and throughout the process... Is this the real problem that needs to be solved? Is there any easier way to get the effect I'm going for? Is this essential to the project? Is this part of the essence of the project? ]

Now that we’re getting down to the wire, I’m committed to cardboard as a building material, mostly as an aesthetic choice, but also because there is not enough time for me to learn the AMS laser cutting process. Prototyping in cardboard can be fast, but constructing in cardboard can be time-consuming.

Pulley Support Redesign and Construction-1 Pulley Support Redesign and Construction-2 Pulley Support Redesign and Construction-3 Pulley Support Redesign and Construction-4 Pulley Support Redesign and Construction-5 Pulley Support Redesign and Construction-6 Pulley Support Redesign and Construction-7 Pulley Support Redesign and Construction-8 Pulley Support Redesign and Construction-9 Pulley Support Redesign and Construction-10 Pulley Support Redesign and Construction-11 Pulley Support Redesign and Construction-12 Pulley Support Redesign and Construction-13 Pulley Support Redesign and Construction-14 Pulley Support Redesign and Construction-15 Pulley Support Redesign and Construction-16 Pulley Support Redesign and Construction-17 Pulley Support Redesign and Construction-18 Pulley Support Redesign and Construction-19 Pulley Support Redesign and Construction-20 Pulley Support Redesign and Construction-21

posted by Michael at 12:39 am  

Saturday, December 1, 2007

Shaft (can you dig it?)

Today I converted my pulleys to work with the new detection strategy. Instead of using the outer rim of the pulley to rotate the mouse ball, I’m going to attach the optical encoder wheel to the end of the pulley’s shaft. To avoid building the pulleys again, I’ve decided to patch up the hole where the bearings were seated.

Hub replacement-0 Hub replacement-1 Hub replacement-2 Hub replacement-3 Hub replacement-4 Hub replacement-5 Hub replacement-6 Hub replacement-7 Hub replacement-9 Hub replacement-11 Hub replacement-12

posted by Michael at 1:09 am  
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