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Symbiotic Synth

A self-sufficient audio biofeedback device

The Symbiotic Synth is a low voltage oscillator that is powered as well as controlled by the human body, thus an audible bio-feedback can be made possible.
It was invented and designed by Wolfgang Spahn for the the exhibition and the workshop I, Machine, and Energy Harvesting by Mindaugas Gapševičius and Wolfgang Spahn as part of the exhibition Shared Habitats in MO Museum, Vilnius, Lithuania in May 2019.

The Symbiotic Synth uses as the only power source the body temperature and drives with that an electric oscillator. The difference of the body to the environment temperature can generates some millivolt - the so called Seebeck Effect. With some tricks and High Tech in form of the Small Energy Harvesting Chip: LTC 3108 one can convert that small amount of energy into some decent voltage and an astable multivibrator circuit can be powered with that. It will oscillate in a audible range depending on the setting of the potentiometer. And because the headphone are actually part of the oscillation circuit one can listen to the sound, too.
In attaching some light, pressure, skin and temperature depending resistors to the circuit one can have variations of the sound based on the human body and its functions. The generated sound will change depending on breath, heart beat, skin resistance and body temperature.


With all that both is possible to power and to modulate a synthesizer with the own human body. And because the generated sound will stimulate the body function, too, the Symbiotic Synth can be called an self-sufficient audio biofeedback device.

Schematic



Paper PCB

These are the Paper-PCB designs. Here one can read how to make a real board out of it: Manual. For the SMD soldering one can find some help here: SMD Solder Manual.


symbiotic_synth_02.zip


Parts

  • Resistors:
  • 3x 22 kOhm
  • Capacitors:
  • 1x 330 pF
  • 1x 1 nF
  • 2x 22nF
  • 1x 1 μF
  • 2x 220 μF
  • Diodes:
  • 1x low current LED
  • Semiconductors:
  • 2x BC547 transistor
  • 1x LTC3108 DC DC converter
  • Mechanical:
  • 2x adapter board SSOP 16pin
  • 2x 8 pin strip
  • 1x 2pin strip
  • 2x pin header, female 1×2
  • 1x jumpers
  • 1x mini switch
  • 2x mono mini jack socket
  • Potentiometers:
  • 1x 100 kOhm
  • Miscellaneous:
  • 1x Peltier element
  • 1x cooler
  • 1x airplane headphones

LTC 3108 module

In the Symbiotic Synth the LTC3108 and a transformer together with some capacitors are build in.
This part of the circuit has the same functionality like on of the LTC3108 module one find on e-bay:
https://www.ebay.com/itm/Body-heat-energy-harvesting-device/332328658257


Usage of the LTC3108 module

The board has two outputs:
Vout1 with selectable voltage and Vout2 which follows Vout1 in terms of voltage level.

Jumper Setting:

 1+3 Vout = 5V
 1+4 Vout = 4.1V
 2+3 Vout = 3.3V
 2+4 Vout = 2.35V

Pinout:

 S - additional storage element
 V1 - Vout1, up to 5mA of output current
 V2 - Vout2, up to 300mA output current
 L - LDO
 G - Ground\\

Acknowledgment

Thanks to by Mindaugas Gapševičius for all the help and support.

Supported by Nordic Culture Point.
In cooperation of Institutio Media.


All contents are Copyright © 2019 by Wolfgang Spahn. All rights reserved.