finger bend etextile sensor WILLPOWER STUDIOS

Finger Bend Sensor

Finger Bend

is a bend sensor created to find a way of making finger bends inside of a glove, control light and sound.

The idea behind this glove is to then connect it to a body suit with other eTextile sensors for Immersive Audiovisual Performances.

The glove will also have touch sensors at the tips and a gyroscope for sensing movements in both physical and virtual spaces.

What inspired me to create this project was the vision of performing freely through body movements.

It is our innate interface. From my view, it is the obvious tool, instead of a trackpad, mouse, tablet, controllers, joysticks…

 

Inspiration: KOBAKANT’s sheath bend sensor.

 

Finger Bend is part of The E-Textile Summercamp’s Electronic Textile Swatch Exchange

The E-Textile Summercamp‘s Swatchbook Exchange is a platform for sharing physical work samples in the field of electronic textiles.

The exchange wishes to emphasize the importance of physicality and quality workmanship in an increasingly digital world.

 

Materials:

× Stretch Piezoresistive Fabric

× Copper Thread

× Stretchy Jersey Fabric Base

× non-conductive fabric

× non-conductive thread

Tools:

× Sewing machine

× LED

× Breadboard

× Computer with arduino and the library for the microcontroller* you are using if it is not yet installed

× USB cable

× Lighter or heat gun (for shrink tube)

*Examples of Microcontrollers: Arduino Uno / Nano / Teensy / ESP32

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How the Finger Bend is made:

Sheath Finger Bend Sensor eTextiles

The illustration above was inspired by plusea’s drawing.

 

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Let’s make it !

 

Steps

  1. Cut the stretch jersey fabric to the length of your finger from the knuckle to the beginning of your nail and width of ~ 8 cm.
  2. Cut a piece of stretchy piezoresistive material and top fabric, both at the same size, similar to the photos below.
  3. Place piezoresistive stretchy fabric in between the base and top fabrics.


Sew 3 lines to slide the 2 copper threads in between them


  1. Cut extremities for closing
  2. sew the ‘inside’ to close
  3. Turn it inside out
  4. Slide a finger through it to feel the size
  5. Do a few bends to make sure it fits around your finger nicely.


  1. Slide copper thread through pathways with a tight knot at the entrance before going through hole
  2. Circle pin with copper thread
  3. Slide pin through shrink tube
  4. Use head gun or lighter to shrink it on pin and copper thread.
  5. Do the same with the next thread

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How to test it:

Connect the copper threads pins to alligator clips, and connect those to a multimeter with the ohm measurement selected.

Observe the change in ohms as your finger bends.

Make sure the copper threads do not touch 😉

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Programming a microcontroller to control LED by using Finger Bend:

Setup:

The Longer pin of the LED goes to pin 4 of the board.

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arduino code:

// start

// WILLPOWER @ Swatch Exchange 2021

#define LED_BUILTIN 13
#define LED 4

int bendSensorValue;
int light;

// the setup function runs once when you press reset or power the board
void setup() {
Serial.begin(9600);

// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
pinMode(LED, OUTPUT);
pinMode(A0, INPUT_PULLUP);
}

// the loop function runs over and over again forever
void loop() {
bendSensorValue = analogRead(A0);
light = map(bendSensorValue, 740, 840, 255, 0);
light = constrain(light, 0, 255);

digitalWrite(LED_BUILTIN, light);
digitalWrite(LED, light);

Serial.println(bendSensorValue);
}

// end

All Finger Bends are a bit different in terms of the data they are generating, so you may have to calibrate yours.

To do this, after you uploaded your code to your microcontroller, open the Serial Monitor in Arduino and compare the numbers between the highest and lowest… basically when you finger is straight versus bent.

Replace these numbers in the map function from 740, 840 to your numbers.

Keep playing with them until you get the result desired.

( the code is also on github: https://github.com/WillpowerStudios/FingerBend )

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Photos documenting process of making 20 Finger Bend swatches 🙂


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Light Arms

191224 - Light Arms

Light Arms activated. I push a ‘soft button’ to change the colors and trigger animations of the addressable LED, whose light is contained and traveling through a 2mm fiber optic cable…

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Video above > A few weeks ago I wore and introduced my ‘Arm Lights’ while making live beats at Elektro Open Stage in Berlin.


2 bend sensors analog read arduino etextiles

Bend Sensor + Multi-Touchpad Read In Arduino and Visualized in openFrameworks

190524 - Bend Sensor Read In Arduino and Visualized in openFrameworks

2 Bend Sensors being visualized.

Reading serial in oF via ofxSimpleSerial to read both separate inputs.

In Arduino, I’m using the INPUT_PULLUP in order to use the internal 20k ohm resistor as a voltage divider.


A0 + A1 as analog pins for both sensors and the other Ground pins for the other side with the alligator clips.


I learned about creating matrices during Make Your Own Multi-Touchpad Workshop.

We read the serial values using vvvv, a commercial toolkit for visual programming, as well as Processing, a JAVA based language.

Since openFrameworks is my tool of choice, I used it to write an app to visualize Multi-Touchpads.


Light Vest - Process of sewing

eTextile sewing for Light Vest

Sewing the textile enclosure for the fiber optic which to carry the lulu ‘s light.

You can see the copper conductive thread sewed as well.

To support the Research & Development Division of WILLPOWER STUDIOS, please donate HERE

R&D


voltage divider

Voltage Divider - Bend Sensor controls LEDs

190317 - Voltage Divider > Sensor to control LEDs

The player above has 2 videos:

They show the tests of the bend sensor affecting the red led.

The first video uses a Flora board by adafruit.

In the second one, I am testing the ATtiny85 which ended up being the chosen microcontroller.


The sketchbook notes shows how the Voltage Divider works.

It ables me to turn the ohm changes from the sensor into voltage for analog reading by the microcontroller.


bend sensor

eTextile Bend Sensor

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The process of making an eTextile Bend Sensor.

Conductive thread and fabric are used to capture the change in ohms from the bending.

Learned from KOBAKANT


Neoprene Bend Sensor

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Cutting Neoprene to make a bend sensor.


Notes for making Light Jacket.