sock puppet sensors
DESCRIPTION
Sock puppet mouth angle sensor for modulating voice playback with gestures.TRANSCRIPT
PUPPETS WITH VOICESNATALIE FREED
MAS 836
SPRING 2011
Thursday, August 25, 2011
APPLICATION
PICK UP A PUPPET AND MOVE ITS MOUTH TO PLAY BACK YOUR RECORDED VOICE.
EACH PUPPET HAS ITS OWN VOICE, MODIFYING YOUR OWN.
IT SHOUTS IF YOU MAKE BIG MOUTH MOVEMENTS, WHISPERS IF YOU MAKE SMALL ONES.
SPEED OF MOUTH MOVEMENT CHANGES SPEED OF PLAYBACK
Thursday, August 25, 2011
APPROACHES
1. CAPACITIVE SENSING - LOADING MODE
2. ELECTRIC FIELD SENSOR / CAPACITIVE SENSING - TRANSMIT-RECEIVE
Loading Mode (measure I )
• Single Electrode • No cable to electrode • Couples to everything • Hard to adjust sens. area • Used for everything - Stud finders (pre MIR) Theremins, buttons...
• No contact with electrode • 3-object geometry => Hard to do tracking • Can “focus” w. tomograpy => Add more transceivers
REFERENCES [1]
Thursday, August 25, 2011
LOADING MODE
CIRCUIT
LOADING MODE
RELAXATION OSCILLATOR + VOLTAGE FOLLOWER + BUFFER WITH OFFSET
Thursday, August 25, 2011
LOADING MODE
BUILD PROCESS
IRONING FUSIBLE CONDUCTIVE FABRIC TO THICK FELT
Thursday, August 25, 2011
LOADING MODE
BUILD PROCESS
SHIELDINGSENSING ELECTRODE
GROUND
Thursday, August 25, 2011
LOADING MODE
BUILD PROCESS
SEWING LEADS TO ELECTRODE, SHIELDING, AND GROUND
Thursday, August 25, 2011
LOADING MODE
BUILD PROCESS
SEWING SENSORS INSIDE THE PUPPET
Thursday, August 25, 2011
LOADING MODE
RESULTS
ONCE HAND IS IN PLACE, RANGE IS TOO SMALL (ABOUT 2 INCHES) AND OUTPUT IS NOT LINEAR. EFFECTIVELY MEASURES VERY SMALL MOVEMENTS (FROG PUPPET) BUT NOT LARGE (WHALE PUPPET).
Thursday, August 25, 2011
TRANSMIT/RECEIVE
CIRCUIT
1. 125kHz 0 to 5V square wave from ATMEGA to 100V PTP sine wave from resonant circuit.2. output of transmit electrode received as current on receive electrode.3. transimpedance amplifier turns current into changing voltage signal4. high pass filter with (adjustable) amplification reduces noise, raises level to 0-5V for ADC5. envelope follower turns signal into DC voltage for ADC to read
ATMEGA32U4
(Teensy)
transmit electrode
receive electrode
transimpedance amplifier
(inverting)
TLV2374
-+
VCC
VCC
Vbias = 2.5V
TLV2374
-+
VCC
active high pass filter with
amplification(inverting)
envelope followerLC circuit
ADC
125kHz pulse
tuning cap
~47pF
5K Ohms
5K Ohms
10 pF
1 M Ohm
6.8 nF
0-500KOhms
20K Ohms
6.8 nF1M
Ohm
Thursday, August 25, 2011
TRANSMIT/RECEIVE
MICROCONTROLLER CODE
ISR(TIMER1_OVF_vect){ TCNT1=0xFFD9; // set initial timer/counter value (16 bit counter) PORTB ^= _BV(PORTB2); //toggle pin B2}
Using Teensy (ATMEGA32 U4) but can’t use Arduino compiler because it hogs the timers! The square wave ends up looking like this:
Use 16-bit timer/counter 1 to generate square wave:
Instead, use just C/AVR and turn off the other timers, this fixes it.
Thursday, August 25, 2011
TRANSMIT/RECEIVE
BUILD PROCESS
Round protoboards from Radioshack
Op-Amp test board on breadboard (beware when moving breadboard to protoboard, changes in capacitance)
Pockets to hold boards in correct alignment to each other and make boards removable
vinyl-cut electrodes
Thursday, August 25, 2011
TRANSMIT/RECEIVE
RESULTS
HTTP://VIMEO.COM/28166293
Thursday, August 25, 2011
SOFTWARE(WORK IN PROGRESS)
Thursday, August 25, 2011
SOFTWARE
P-TO-P AMPLITUDE OF OSCILLATION OF PUPPET MOUTH AFFECTS GAIN. WHICH PUPPET IS CHOSEN AFFECTS PITCH.
Thursday, August 25, 2011
RESOURCES
1. CAPACITIVE SENSING/ELECTRIC FIELD SENSOR LECTURE NOTES, JOE PARADISO (HTTPS://STELLAR.MIT.EDU/S/COURSE/MAS/SP11/MAS.836/COURSEMATERIAL/TOPICS/TOPIC1/LECTURENOTES/CLASS6-EMSENSORS/CLASS6-EMSENSORS.PPT)
2. TEENSY REFERENCE - PJRC (HTTP://PJRC.COM/TEENSY/)
3. FABFISH (HTTP://BDM.CC/FABFISH/)
4. FILTERS/AMPLIFIERS REFERENCE (HTTP://WWW.ELECTRONICS-TUTORIALS.WS/FILTER/FILTER_6.HTML)
5. ATMEGA TIMER/COUNTERS (HTTP://WWW.ELECTRONICSBLOG.NET/EXAMPLES-OF-USING-ARDUINOATMEGA-16-BIT-HARDWARE-TIMER-FOR-DIGITAL-CLOCK/
MANY THANKS TO: BRIAN MAYTON, MARK FELDMEIER, DAVID CRANOR, NAN-WEI GONG
Thursday, August 25, 2011
Thursday, August 25, 2011