AWLS

1
The cocktail shaker - Update 11/17/03 -
Motivation

• Relate motions in cocktail making to music

What we challenge

• Can shaking motion of an object be a musical
  instrument
• or a music controller ?
• (like tambourine, maracas, hand-bell,
  ... ?)
• Can the attractive motions be mapped to
  attractive music?
• Can motion of the liquid inside be used for
  music?

2
Schedule and tasks
Prototype 1 ( 11/17)

• Design a simple prototype
• Make the prototype
• Write a test program for AVR
• Test various Pd programs / music on the
  prototype
• Determine how to map the motion / device to
  music
• Check errors, modification, expansion, etc.

80
Challenging Test ( 11/17)

• Design test schemes for alternative sensors
• Test the alternative sensors

3
Schedule and tasks
The cocktail shaker (11/24)

• Design the perfect shaker
• Make the shaker
• Adjust the AVR program and Pd to the new shaker
• Test various Pd programs and/or music

Performance Planning (11/24)

• Find a good example(s) for the presentation

Training (11/30)

• Train a performer(s) severely!

4
The First Prototype
Basic motions of the shaker
Conservative way
Challenging Test
Enc.
LED
Accel.
Photo Detectors
FSRs
FSR
(liquid motion detection)
(no relation to motion of the liquid inside)
5
Hardware
On going
Done
Not yet
6
Software (AVR)
Initialize
DC Bias subtraction (128pts moving average)
Get A/D data
Check Buttons
LPF (2nd order IIR, Fc 5Hz)
Process accelerometer
Onset detection (y-z energy peak / z sign)
4ms (250Hz)
Send Values (OSC/Pd) onset rotation value
encoder counts buttons FSR value accel.
x, y, z value motion energy
Rotation motion extraction (x energy _at_ yz energy
small)
7
END
8
Typical Accelerometer Output
Raw A/D data
x 5
X
x 5
Y
Geometry
y
z
x
Z
A/D Value
Time (s)
9
DC Bias Subtraction
DC Bias
Raw A/D data
X
Y
Z
A/D Value
Time (s)
10
DC Bias Subtraction
Raw A/D data
Bias removed
X
Y
Z
A/D Value
Time (s)
11
LPF
Raw A/D data
LPFed data
X
Z
A/D Value
Time (s)
12
Discrimination of Shake and Rotation
How to discriminate the motions ?
up
Geometry
y
z
x
down
Restriction
Do not hold the shaker upside-down! (or
horizontally!)
13
Discrimination of Shake and Rotation
Geometry
up
y
z
x
down
all values are possible z value is positive
... bottom negative ... top
x value is dominant
Extract x value in the interval in which y
and z values are small.
Detect peaks of the energy in y-z
plane. Direction can be detected from the sign of
z value. Peak energy can be calculated from x, y
and z values.
14
Onset Detection
Map a bottom point of the shaking to an onset.
acceleration energy in y-z plane
LPFed z value
acceleration energy in xyz space
15
Rotation extraction
LPFed x value
Energy in y-z plane
Inhibition function
Extracted rotation
((roughly) inverse of LPFed y-z enegy)
16
Michael's Question
Why the cocktail shaker ?
1. Because it is the ONLY device to produce the
sound
If we could use motion (or attributes) of liquid
in music.
2. Because it is a NATURAL device to produce the
sound
e.g. Synchronization of the cocktail making and
music. e.g. Natural mapping from the shaking
motion to music.
3. Because it is ATTRACTIVE!
Isn't it attractive if the shaker produce a funny
sound??