5. E-textiles¶

Inspiration¶

I found a lot of inspiration in the book, Textile Visionaries, which can be previewed found at the link here

Barbara Layne¶

Photos from Textile Visionaries: Innovation and Sustainability in Textile Design by Bradley Quinn

https://papers.cumincad.org/data/works/att/sigradi2005_085.content.pdf

Potential Uses¶

Often when I'm creating something I like to start by thinking of potential practical uses

Dog Collars¶

There are lots of light up dog collars on the market, like this one and I think E-Textiles is a great idea to take it one step further. This idea could be used to make light up dog harnesses, dog harnesses that alert you when they're not put on correctly, or dog harnesses that vibrate when they're being pulled (my dog often tries to slip out of his).

Reading Lights¶

This is the one I'm most excited about and want to continue to work on, but didn't get a chance to finish this week.

I would love to make a wearable reading light that's comfortable and feels just like a headband, like a headlamp used for the outdoors, but comfortable and less bright. This popular headband typically used for facewashing provides the perfect amount of space and adjustability for lights at the end and would be much more comfortable than a typical headlamp.

Photo by Nick Gosset on Unsplash

Important Things to Note¶

Circuit a closed loop of electric current flowing from a power source to various components

V = I x R Voltage = Current x Resistance

LED Power ~ 20 mA

Resistance = ( Voltage(battery) - Voltage(LED) )/Current When calculating the amount of resistance to add to a circuit, you need understand how much voltage remains after the LEDs in the circuit are powered. It's important that you don't have too much leftover power in the circuit that's not being consumed.

LED positive vs. negative side flat side of LED indicates negative side [add photo]

Series vs. Parallel Circuits

Analog vs. Digital

Units

	Units
Current	amps (A)
Resistance	ohms (Ω)
Voltage	volts (V)

Arduino¶

What is an Arduino?

Tools & Materials¶

Arduino UNO
Arduino IDE
Velostat
Conductive fabric
Conductive thread (silver)
LEDs
Lithium 2032 battery
Battery holder
Bread board

Process and workflow¶

My first circuit¶

The first sensor I made was a quick hack to understand how a circuit works. I created a parallel circuit with two LEDs and on either side I sewed the conductive thread into conductive fabric and I covered one side with velostat. This allowed me to increase and decrease the voltage (analog) by adding pressure to the velostat. This design (once cleaned up) could be used to make a bracelet.

My first analog circuit test + Arduino with digital output¶

To test out the Arduino, I used my first test circuit (above) and connected it to the arduino and to the bread board.

Arduino input: My sensor
Arduino output: LED on breadboard

The code I wrote changed the pace of blinking of the LED on the breadboard in accordance with the amount of voltage being sent to the Arduino from my sensor. So when the circuit on my sensor was not complete (i.e., bracelet open), the light blinks slowly. But when I close the bracelet and thus complete the circuit the LED on the breadboard will blink quickly. For this experiment I used my analog sensor as a digital input (on/off), but I could easily change the code to analog by adding a range of inputs for the Arduino to collect and add more blinking speeds to the output.

Code Example¶

Use the three backticks to separate code.

int analog_sensor_value = 0; 

void setup() {
  // put your setup code here, to run once:
  // initialize digital pin LED_BUILTIN as an output
  pinMode(3 , OUTPUT);
  pinMode(A5, INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  analog_sensor_value = analogRead(A5);
  Serial.println(analog_sensor_value);
  delay(100);



  if (analog_sensor_value> 350) {
    digitalWrite(3, HIGH);
    delay(1000); //milliseconds
    digitalWrite(3, LOW);
    delay(1000); 
}



  else {
    digitalWrite(3, HIGH);
    delay(100); //milliseconds
    digitalWrite(3, LOW);
    delay(100); 
}

  }

My second analog circuit test¶

I tried to move a prototype for my wearable reading lamp (though I will need stronger lights for the final). I tested this with one light, but since I hand sewed it and I'm not so strong with hand sewing it was a bit messy. I got it to work in the video below, but the next day the light no longer went on. I decided instead of debugging to make another simpler and cleaner circuit (see below) that could later be expanded into the headband. So I will be returning to this design later!