Michael Ang

Hyrobot Mark I makes his big debut! Saturday April 29 at Tonic! Hydrobot Mark I will perform “Hydrobot Learns to Surf” with visuals by Ilteris Kaplan.

TOOL: An evening of novel performance technologies

Performances from the graduate Interactive Telecommunications Program (ITP) at NYU grace the upstairs stage at Tonic with interactive installations down in subTonic. Projects from classes such as “New Interfaces for Musical Expression” and “Live Image Processing for Performance” put the “live” back into electronic music performance. Presented by ITP instructors Jamie Allen, Gideon D’Arcangelo and Luke Dubois. Installations in subTonic from 7pm. Stage show upstairs begins at 8pm.

Saturday, April 29

TONIC
107 Norfolk Street
New York, NY 10002
$12, free with NYU ID
212-358-7501
http://www.tonicnyc.com
Tonic is located at 107 Norfolk Street between Delancey and Rivington Streets in Manhattan’s Lower East Side.

Performers include:
Jeff Gray
Todd Makinen
Mike Ang
Nick Sears
Langdon Crawford
Ryan Holsopple
Josh Knowles
Michael Harari
Britta Riley
Chris Kucinski

For further information on the show, contact jamie at nyu dot edu or gideon at nyu dot edu.
For more information on the Interactive Telecommunications Program at NYU: http://itp.nyu.edu.

Working in the lab. Here’s a quick and dirty drill guide for the Airpax LB82773-M1 stepper motor.

Airpax LB82773-M1 drill guide (.ai)
Airpax LB82773-M1 drill guide (.png)

LEMUR is building a new studio/art space on Third Ave in Brooklyn. The place is gigantic, with space for a machine shop, offices, gallery and teaching. There is a tremendous amount of work to do to get it into shape, but it’s exciting times indeed. Watch for much more LEMUR activity throughout the summer! The pictures show the raw beginnings — in the near future they will be a quaint reminder of how far we’ve come

Pictures of LEMUR studio in construction

Ah, April, when a young ITPer’s thoughts turn to… oh! crap! so! much! to! do!

Pictures from Hydrobot interrupter disk testing

Last night I tested the Hydrobot interrupter disks attached to stepper motors. The KP4M4 stepper was way to weak, but the ones I got from Jameco should work well. They can go pretty fast, but I will have to start them slow to avoid missing steps. The “spider” shaft couplers (rubber cross between two metal pieces) I got from Jameco are nice but using them means I need some way to trap the interrupter disk shaft axially since the coupler doesn’t provide any axial attachment.

The current plan to control the flow of water from the nozzles is to have spinning disks which interrupt the flow. Last week I cut some 5″ disks with 1/4″ mounting holes from acrylic using the laser cutter at NYU. I bought some Airpax LB82773-M1 5V 0.8A bipolar stepper motors from Jameco and some SN754410NE dual h-bridge drivers from Sparkfun. I got 7.5 degree step motors which should give a chunky step pattern.

Here are the test patterns. The final disks may be in acrylic or aluminum. I will probably bend the vanes to direct the flow of water down. I still need to design the housing for the motors. Either custom built acrylic or adapted from an existing water-tight box.

Illustrator source file

The Hydrobot performance will take approximately five minutes and represents a single cycle of the ocean from high tide to low tide and back again. It should give the feel of a good surfing session with high tide being dull, building waves as the tide ebbs eventually leading to poor conditions at low tide, then better conditions again on the way to the end of the day. Each of the four jets of the hydrobot can be thought of as different points (underwater rocks with the potential to create breaking waves) on a beach which faces an incoming ocean swell. Each point is assigned its own height value, which determines if incoming swell will pass over the point, break on it, or be closed out (break in a turbulent way).

If an incoming wave is more than one wave height above the point, it passes without breaking. If a wave is less than one wave height above the point, it will “break”, and the jet for that point is open for a period of time proportional to the height of the wave over the point. If the height of the wave when it breaks is too high, the wave is closed out and the jet will pulse rapidly and irregularly.

As the piece begins at high tide, the points are submerged and the waves do not break. The water from the jets is in this case constant. As the tide ebbs, the points will begin to break. As the tide lowers further, the points will become closed out, and the piece will be cacophonous with rapid bursts and irregular rhythms. As the tide rises, the piece returns to rhythm and then to a steady stream.

My blue flower will use inductive charging. I took apart an Oral-B CrossAction Power Max toothbrush ($18 at K-Mart) to see how it works and see if it would be useable in my project.

Charger hacking and coil construction pics

The toothbrush side is remarkably simple. There is a coil attached directly to a battery (no rectifier) and a switch which physically connects and disconnects the battery from the motor assembly. The motor appears to be similar to that used in a pager. The attachment on the shaft has an inverted cone offset from the axis of the motor that loosely connects to a metal rod that goes up to the toothbrush head. The design is very elegant, using a minimum of parts and materials.

The base is completely filled with an epoxy or rubber (finding epoxy is the hacker’s worst nightmare!) There is a circuit board that I didn’t free from the epoxy and coils of magnet wire. The magnet wire is formed into stranded wire and then coiled (as opposed to a simple bobbin of magnet wire). The base seems more or less useless for hacking because of all the epoxy. Interesting to see that the shape of the coil is pretty loose.

For my own inductive charger experiment I used 22ga magnet wire on a spool as the primary and 30ga magnet wire coiled around a screw as the secondary (in a transformer, power is transferred from primary to secondary). Using about 0.9 amps at 8V and 5.4kHz I could get an LED to light at 2.6V. There seemed to be a voltage peak at that frequency with this arrangement. The primary had an audible whine, which isn’t too surprising. Now the trick is to figure out the most suitable combination of coil geometries, drive frequency, drive voltage, and core type to get the power I need.

For my Living Art final project I’m continuing my blue flower. It will be housed in an acrylic vase that is a wireless inductive power source. If the flower is removed from the vase and its nourishing electric field, the flower will droop and dim.

Concept sketches — results of a marathon single sitting SketchUp session.

Flyby video, 1.5MB DivX 5
Flyby video, 3MB Indeo
SketchUp source file

Front view (labelled):

Side view:

Rear view (labelled):

Pseudo-isometric view:

The LEMUR installation at the National Gallery in D.C. will have it’s last show on May 7th. But on May 6th there will be a special presentation of the complete 22 minutes of Ballet Mécanique and other works for the mechanical orchestra. If you haven’t seen the installation, it’s worth checking out, and I plan to be at “Bye, bye, Ballet Mécanique” on May 6th!

From the LEMUR announce list:

Hi,

LEMUR and the Ballet Mecanique installation at the National Gallery
of Art have been making a big splash in the press. Below are links to
a number of audio, video and print stories which have appeared since
the opening.

Also, due to schedule changes at the Gallery, the installation will
now end a week earlier than we recently posted. The last performance
is scheduled for Sunday, May 7th at 1 pm.

However, a new event, “Bye, bye, Ballet Mecanique,” has been added.
On May 6th at 4 pm, the full 22 minute version of the piece will be
performed, as well as several other pieces for the orchestra. We will
post more details here when they become available, or check
http://nga.gov closer to the date.

Thanks for reading,
Eric Singer
LEMUR Director

*** LEMUR and Ballet Mechanique in the News ***

An interview piece on Ballet Mecanique with me and Paul Lehrman,
which aired recently on Weekend America from American Public Media:
http://weekendamerica.publicradio.org/programs/index_20060318.html

A review of the DADA exhibit on NPR’s Fresh Air. The section on
Ballet Mecanique begins at 4:03 :
http://www.npr.org/templates/story/story.php?storyId=5323011

A short clip from CBS Sunday Morning:
http://www.antheil.org/audio/CBSSundayMorningWeb.mov

An article on New Music Box including an audio clip from the installation:
http://newmusicbox.com/article.nmbx?id=4561

An article which appeared in the Washington Post shortly after the opening:
http://www.washingtonpost.com/wp-dyn/content/article/2006/03/19/AR2006031901166.html

An article from the Washington City Paper:
https://secure.washingtoncitypaper.com/cgi-bin/Archive/abridged2.bat?path=q:\DocRoot/2006/060317/photo4

A review on Other Minds, including great photos of the installation:
http://www.otherminds.org/shtml/Antheilrobots.shtml

Continuing in my direction of creating electronic systems which are in some way based upon the principles of nature, I would like to create a system where electronic flowers and electronic beetles interact in a symbiotic relationship.

A number of electronic flowers will be spread around a small “arena”. Each flower will have LEDs to attract the beetles and metallic stamen to provide electricity which “feeds” the beetles. The LEDs will pulse in a pattern which indicates the “genetic heritage” of the flower. As a flower is visited by a beetle the genes of the flower will be modified according to a genetic code carried by the beetle. When a beetle visits a flower it picks up the genetic code of that flower and can bring it to a different flower by visiting it.

The initial set of genes for each flower will be determined randomly and each flower will have a unique set of genes. That’s each flower will have a unique set of pulsing visible in its LEDs. Initially the beetles will not carry any genes — they must pickup a set of genes by visiting a flower.

The beetles will be programmed to look for sequences of flashing LEDs and move in that direction to search for a power source to feed from. Each robot will have a small battery which must your charge by visiting different flowers. One of flower is visited and it will provide a certain amount of power to the beetle and then the flowers power will be temporarily exhausted. If the flower is not visited within a certain amount of time it will “die”.

The expected behavior of the system is that flowers which are difficult to reach or which exhibits LED contraction patterns not favored by the beetles will die. Preferential patterns should begin to spread between the different flowers as they cross pollinate. Beetles which are unable to reach different flowers will also die.

The initial conditions will determine whether a stable system of living beetles and flowers will result or whether the complete system will “die”.