It is mostly a standard 8" tape knife, like the kind drywallers use to
tape joints in sheetrock. It is a tool that gained my respect when I
hung some sheetrock in our house in D.C. When Bill Verplank
asked
our class
to observe an expressive activity, this
is what I chose to share with the class.
You will notice that this tape knife comes with features not found on
the ones at the Home
Depot.
First, the round thing on the blade is a piezo-electric transducer
which I use to convey the sound of the blade to the sound card of the
computer. The
other bit of gear is a 100mH inductor coil. That is paired with a
little capacitor to form a resonator,
which puts out a very strong 50kHz sine wave.
An antenna array behind
the playing surface picks up the signal, and the circuit pictured below
sorts out the
signal strength for each part of the receiving array. This part borrows
very heavily (that is to say is directly copied from) Max
Mathews' radio
baton. Max was very kind to share his design with me, and
even helped me shake out a few bugs.
Also visible on the circuit board is my trusty Arduino. This is not
the board we used at ccrma, but it is
similar, comes with a handy IDE, and is very replaceable!
It has a little atmega8 microcontroller, which runs this
little program,
which reads the output of the receiver circuits, and sends serial
messages to the laptop over the usb.
These messages are read by this pd patch: Radio Tape Knife.pd,
which calculates the position of the knife, and also does the synthesis
based on position and the input from the piezo.
This is a video of a class demo, with me playing cello while hooked up
to an electrode reading a score that is at least somewhat generated by
my galvanic skin response. Rob Hamilton, designer of the gsr score
generator, is improvising on the RTK. Mudder-Score.mov
Here's an audio clip of the Radio Tape Knife: foam2.mp3
Here's a piece in which I am actually applying spackle to a big sheet
of drywall: spackle2.mp3
RTK controlling 4 different patches at the same time: foam boil.mp3
And a video of simialr material in a horizontal plane: table.mov
Here
are a couple duets for RTK (garden trowel version) and cellomobo, made
in preparation for my show at the Stone (10/4/07) with the Verge
Ensemble in New York City. bedone.mp3 bedtwo.mp3
I built an atmega8 into the breadboard, so now I can use my Arduino for
another project.
This is the Radio Tape Knife
