Imaginary Drum Kits

1
Imaginary Drum Kits

• Hyemin Chung and Jaewoo Chung
• May 17th, 2005

2
Backgrounds
Theremin
Spirit Chair
ExpressiveFootwear
Digital Baton
3
Goal

• Mobile full drum kit without real drums or
  instruments
• Can detect hitting positions.
• By capacitive sensing
• Can detect hitting timing and velocity.
• By accelerometers
• Can be easily moved and carried.
• Can run without external installations.

4
Implementation
CapacitiveSensingTransmitters
Circuitsin the bag
Accelerometers
CapacitiveSensingReceivers
5
Structure
Sounds
TX0
TX1
TX2
Visuals
Stick0
Stick1
RX0
AC 0
RX1
AC 1
6
Capacitive Sensors

• Detect the location of the drum sticks.
• Use 3 transmitters to calculate the location.
• Work in transmit mode.
• To minimize the noise from the body
• Transmitters are on the body.
• Receivers are in the sticks.
• Are sampled by 60 times and averaged.

7
Capacitive Sensors
8
Capacitive Sensors
9
Sampling
10
OP Amp

• MAX475
• Uses a high pass filter to avoid 60Hz noise.

11
Accelerometers

• ADXL311JE
• At the tips of the drum sticks
• Detect the impact and velocity.

12
PIC

• Controls the capacitive sensing.
• Converts analog signals of accelerometers and
  capacitive receivers to digital data.
• Sends data to the computer every 5 milliseconds.

13
Software

• Detects the impact
• Calculates the position of the drum sticks
• Generates sounds and visual effects

14
Difficulties

• Sensing area is larger than the sensor-area.
• Lots of noise come from users body and all
  around the world.
• Sticks bounce, re-bounce, and go up again.
• Base levels ceaselessly vary by users movements
  or shapes.
• Delay is a big problem in musical instrument
  systems.

15
Demo
16
Future Works

• To make it more accurately by more tuning and
  noise deduction
• To detect and apply the velocity of hitting
• To make more portable, wearable, and compact

17
Thank you