5. E-Textiles and Wearables I#

My task this week was to experiment with different conductive materials. In addition, I have built and tested various circuits. The result of the week is a textile with an integrated circuit. LED’s are lit up and controlled by a built-in switch.

Basics#

Conductive materials#

In our lab, I found various conductive materials that I tested for conductivity.

Electrical circuit materials#

To build the circuits I needed the following parts:

Experiments with conductive materials#

First I printed a rectangle with conductive PLA directly onto a piece of fabric with the 3D printer. I fixed a 9V battery with copper tape at the ends and tested the conductivity with an LED. The printed filament has a very high resistance. The electricity can flow successfully only over short distances.

It is similar with BARE electric paint. The color has a very large resistance. The electricity flows better once the paint has dried. The copper tape has the best conductivity in my experiments.

Arduino and components#

To build the circuits with an arduino I also needed the following parts:

Electrical circuit with LED`s#

To build a simple circuit with LEDs, I connected the 9V battery with the two poles at the breadboard. The resistances in front of each LED were switched in series. You can see this on the following picture:

Electrical circuit with LED and switch (digital)#

The next step was to create a digital circuit with the arduino, a LED, a resistance and a switch. The result you can see in the following

Arduini_switch from Eva Ismer on Vimeo.

In the following video you can see my digital soft sensor with copper tape, a coin cell battery, a LED, copper taffeta and felt. The felt is between two pieces of copper taffeta. Small holes are punched in the middle of the felt to close the circuit when the switch is pressed.

digital sensor_swatch_DIY from ViNN:Lab on Vimeo.

Electrical circuit with LED and potentiometer (analogue)#

Then I create an analogue circuit with a potentiometer to regulate the intensity of the LED. You can see the schematic circuit on the picture. How the switch works you can see on the video here:

Arduino_Potentiometer from Eva Ismer on Vimeo.

In the following video you can see my DIY soft sensor with EeonTex and Velostat. Its a kind of potentiometer. The stronger you press the button, the brighter the LED will light up.

analogue sensor_DIY from ViNN:Lab on Vimeo.

The code#

The code for the circuit was written in the arduino software.

int eingang= A0; //Das Wort „eingang“ steht jetzt für den Wert „A0“ (Bezeichnung vom Analogport 0)
int LED = 13; //Das Wort „LED“ steht jetzt für den Wert 13
int sensorwert = 0; //Variable für den Sensorwert mit 0 als Startwert

void setup() //Hier beginnt das Setup.
{
pinMode (LED, OUTPUT); //Der Pin mit der LED (Pin 13) ist jetzt ein Ausgang.
}

void loop()
{
sensorwert =analogRead(eingang); //Die Spannung am Drehregler wird auslesen und wie im vorherigen Sketch als Zahl zwischen 0 und 1023 unter der Variable „sensorwert“ gespeichert.
digitalWrite (LED, HIGH); //Die LED wird eingeschaltet
delay (sensorwert); //Die LED bleibt für so viele Millisekunden eingeschaltet, wie der Wert von „sensorwert“ es gespeichert hat
digitalWrite (LED, LOW); //Die LED wird ausgeschaltet
delay (sensorwert); //Die LED bleibt für so viele Millisekunden ausgeschaltet, wie der Wert von „sensorwert“ es gespeichert hat.
}
//Der Loop-Teil wird nun erneut gestartet. Wenn sich der Wert des ausgelesenen Drehreglers ändert, dann ändert sich auch die Zeit zwischen den Ein- und Aus-Phasen der LED. Das Blinken wird dadurch schneller und langsamer. Das längste delay beträgt in diesem Sketch 1023ms (Millisekunden). Wenn man längere delays benötigt, dann baut man eine kleine mathematische Zeile in den Code ein. Beispiel: Man ändert die Zeile „sensorwert =analogRead(eingang);“ in „sensorwert =analogRead(eingang)*2;“ Damit wird der abgespeicherte Sensorwert um den Faktor 2 vergrößert. Da längste delay wäre dann 2046ms usw…

Conductive materials and fabric#

Project of the week - digital switch#

Let’s start with some circuits in combination with fabric. The belt buckle in this project acts as a digital switch that turns the circuit off/on.

To make the LEDs easier to stitch into position the legs can be formed into eyelets. This can be achieved easily by forming the legs of the LED with a pair of pliers. The reason for creating the eyelets is to ensure the thread can be securely attached the LED, without the possibility of it being easily dislodged.

To change the battery easily, I used a battery holder that can be sewn onto the fabric. The circuit with battery and LEDs, I have integrated into a belt. The belt buckle is the switch to close the circuit.

The felt butterflies were sewn with glow in the dark yarn to set a highlight.

analogue pressure sensor#

Here you can see my analogue pressure sensor with copper fabric, Karl Grimm yarn, Neopixel, Gemma and EeonTex. If you press the arrow (EeonTex) the circuit will be closed and the neopixel will light up. The stronger you press the brighter the LED will be.

analogue sensor copper fabric from Eva Ismer on Vimeo.

analogue sensor neopixel from Eva Ismer on Vimeo.