Flex Signal

 

Who is the intended user?

Experimental music makers.

What is the intended application? Note that this can be either a practical, solution-oriented application (design?) or something more exploratory (art?).

Takes advantage of our hand dexterity to create a simple interface and synthesizer, with potential for expanded application through interacting with media and a users environment.

What is the response mechanism? Physical actuators? Something screen-based? Sound?

Resistive fabric activates a PMW signal from Arduino, which is amplified through a TDA7297 and a DAEX32Q-4 Exciter. The shape and pressure of the users hand also creates a filter and amplitude modulation.

If you are sending data to another software what is it and what communication protocol will you use?

The data from the resistive fabric is translated by Arduino into PMW signals.

Where does the interface physically live on the body? How does that affect how the user interacts with it?

The interface is embedded in a two layer glove. The hand is a highly dextrous part of the body, enabling a diverse and modular interface in a small area. The sensors are placed along flex points of the hand, following flexor digitorum profundus.

Is the textile interface sensing actions of the wearer or of someone else?

The wearer.

What is your material palette, conductive, resistive, and non-conductive?

Resistive, while pressing on the resistive band results in high numbers for data received, seemingly creating a pressure sensor.

What is the scale of the interface? Tiny? Huge? Somewhere in between? What body part is meant to activate it?

The size is fairly small, while the Arduino Uno and amplifier are the larger components. The audio output requires a ATmega328P, and does not require the full TDA7297 module. The necessary components can be picked out for a more compact circuit to be joined with the glove.

What mood / attitude / approach are you hoping to incite in your users? Is a delicate interaction? Rough? Tender? Formal?

While the glove can create a loud and aggressive sound, this can be changed depending on the material used to amplify the vibrations. The vibrations can be light or strong depending on the level of amplification from the TDA7297 module. The interaction can be rough or tender depending on user settings.

What type of switches / sensors are you constructing? Digital, analog, or both? How many?

One analog sensor through resistive fabric in the working prototype. There is a second one across the dorsal interossei, that takes advantage of spreading fingers. This is not wired at the moment.

What is the mapping between the sensor data and whatever is responding to it? How many modes of interaction are there and what are they?

The synth takes advantage of manipulating Arduino’s PMW cycles to produce lower frequencies than AnalogWrite() is designed for.

Findings that you think would be useful to other people working in this area.

The main difficulty when working with resistive sensing fabric is that the feedback will change when sewn/attached to another material. The solution for this was to create a needle out of single strand 20 AWG wire and thread it through the resistive fabric. The wire was bent into a loop and soldered closed.This loop was then sewn into the glove, retaining the resistance from tests before attachment

img_7098 60187574722__cc51f2ef-bbbe-4aad-bcfe-71963819730e

Resistive Fabric Tests

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Arduino PMW modes, explained by Phil Schleihauf

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Bricked the Uno’s At8u2. Phil explained I could upload to the board through a second Uno, bypassing the fried At8u2.

screen-shot-2020-01-31-at-2-13-32-pm

Working Prototype

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Final Prototype

 

 

Context

The research for the piece was originally inspired by Lozano-Hemmer’s “Remote Pulse” installation across the US-Mexico border, consisting of two networked heart-rate sensing stations. When a person places their hands on one station, the person at the other station feels their pulse, as motors vibrate the plates in sync with the other heart-rate.

The early experiments were focused on creating a kinaesthetic communication fabric in response to muscle movement. As motors such as the ones used in haptic feedback interfaces are available in small sizes, the early ideas were were focused on attaching small vibrating modules to clothing.

The possibilities of combining haptic feedback with textile opens new avenues of communication with our bodies and the environment. In the scope of gaming or digital media, haptic feedback clothing would give users the ability to interact more conventionally with virtual environments. Haptic clothing can also be used to augment human awareness, such as motors located in the protective clothing or providing information when senses are experiencing over-stimulation from the environment. David Eagleman’s VEST is an example of communication through combining vibration and sensors. It uses a number of motors attached to a vest that translates incoming audio to vibrations. The user is trained to recognize vibrations with certain inputs, such as a vowel.

The later iterations of the project were focused on translating muscular movement into data. This data could be interpreted in a number of ways, the final output being sound. There are a few notable projects that use the body as a controller for sound, such as Use All Five and Google Creative Lab’s Body Synth. Using computer vision, different parts of your body correspond to changes of parameters within Tone.js. Similarly named, The BodySynth™ is another project where the user attaches electrodes to the body. These signals generated by muscle contractions are measured, analyzed and translated into MIDI. This MIDI input can be mapped to a synthesizer or virtual instrument within a digital audio workstation.

The goal of this project was to combine the sensors, processing, and output within a single wearable, without the need for outboard processing. The first hurdle was Arduino’s AnalogWrite(), which outputs a single frequency. Additionally, Arduino’s Tone library’s lowest frequency is rather high for a vibration module. Through conversations with Phil, another member of InterAccess, I was informed to use the ATmega’s PWM registers directly for more control over frequency. This enabled me to turn the Arduino into a formidable oscillator instead of controlling an outboard program/device like The Body Synth or The BodySynth™. Mounting the Dayton Audio transducer onto the glove was the finial step to create a fully integrated audio device. By using a transducer, parameters of the sound are changed by the users environment and the material the transducer is in contact with. Additionally, the shape of ones hand has an effect on higher frequencies as it creates a low-pass or band-pass filter.

Rafael Lozano-Hemmer, Remote Pulse, 2019

http://www.lozano-hemmer.com/remote_pulse.php

David Eagleman , VEST

https://www.smithsonianmag.com/innovation/could-this-futuristic-vest-give-us-sixth-sense-180968852/

Chris Van Raalte and Ed Severinghaus, The BodySynth™
http://www.pamelaz.com/bodysynth.html

Body Synth, Use All Five & Google Creative Lab
https://experiments.withgoogle.com/body-synth

Bosman, Sal & Groenendaal, B. & Findlater, Jan & Visser, T. & Graaf, M. & Markopoulos, Panos. (2003). GentleGuide: An Exploration of Haptic Output for Indoors Pedestrian Guidance. 358-362. 10.1007/978-3-540-45233-1_28.

 

Code: https://github.com/lclrke/flexsensor

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