5. E-textiles¶

Electronic basics¶

Electrical current => is the flow of electrons in a wire. Electrons flow when you have a “closed loop” – a path from the negative (ground) to the positive terminal of a battery.

Circuit¶

=> closed circuit would allow the flow of electricity between power and ground vs. open circuit would break the flow of electricity between power and ground

voltage (V) => pressure / force between two points
current (I) rate at which the electrical charge flows
Resistance (R) determine how much charge flows through a circuit - Ohms amount of material that resist current flow => measured in ohms => the lower the R more current flows so the higher the R less current flows

Types of circuit¶

General rules¶

Electrons are lazy: electrical energy follows the path of least resistance to ground
Electricity hates waste: all electrical energy in the circuit must be used => otherwise it will dissipate as heat and possible damage to the circuit components

Materials¶

Fabrics threads and yarns:

=> we can use any conductive material any material that allowed the energy to pass

=> consider properties : resistance, stretchiness, solderability, feel substrate & productive process

Hand tools:

scissors
needles
pins
non conductive fabrics
embroidery tools

Electrical tools - alligator clips - connectors - resistors - breadboard - tensiometer - 3V Battery - LED lights - electrical Tape - Aurdino UNO - Arduino IDE

INPUTs¶

=> info or data that enter a system

=> it can be digital (switches - on/off) or analog (sensors - range of values) (fotos de ambos): key differences between them is their output resolution - analog sensors provide variable resolution since they provide a continuous range of values, while digital sensors have a finite resolution determined by the number of bits used to represent the signal.

Digital

=> switches: is a break on a circuit => since the circuit is not complete, no electricity can flow through the components

Momentary switches: stay open as long as you hold them by pressing conductive materials into contact
Toggle switches: press, slip, slide, etc two pieces of conductive material together - its stays open in one possition and close in the other

Analog

=> Sensor: we can use resistance to get a broader range of values - by allowing more current to get through, you can change your Output activity - ex; a led brightness , a sound frequency, a motor´ speed

=> factors that change R:

distance: R increases over d
contact: material that are pressure sensitive will decrease in R when p is applied
surface area: the + s.a - R

Microcrontollers & Programming¶

Arduino => open source microcontroller that can be programed to create specific/reactive outputs and collect data. => Board > Arduino UNO: control leds, read sensors, control leds based on interaction with sensors => In it connect input and output devices

=> Pin : is how INPUTS (button, sensor) and OUTPUTS (leds, motos, etc) communicate with arduino

References

⧫ let's get on with it! ⧫¶

Just remember:

Electricity rules: electrons are lazy + hates waste + circuits are a system
R can be manipulated in 3 ways => distance - contact - surface area create secure connections & keep your circuits clean

First aproximations

Digital switch experiments¶

materials

sewing pins
conductive thread
3V battery
diodo leds
agar bioplastic (surface)
tangerine dehydrated skin

materials

pins
conductive wire
3V battery
two diodo led
embroidery thread
2 hook pins

Arduino¶

Arduino UNO and a led

My first aproach to Arduino consisted on turning on a led

I use d code from Emma Pareschi

    void set up() {
    // put your set up pin, to run once:
    pinmode(3,OUTPUT);
    }

    void loop() {
    //put your main code here, to run repeatedly:
    digitalWrite(3,HIGH);
    delay(1000);
    digitalWrite(3,LOW);
    delay(1000);
    digitalWrite(3,HIGH);
    delay(2000);
    digitalWrite(3,LOW);
    delay(500);
    }

Analog sensor (ultrasonic)¶

At the BDC we had some sensors and I decided to try the ultrasonic to light a led. This sensor meassures distance and proximity

Materials: connector - diodo led - Arduino uno - ultrasonic sensor

First step is to read de sensor

Emma Pareschi code to read analog sensor:

int analog_sensor_pin = A0;   //change the pin, where the sensor is connected?
int analog_sensor_value = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(analog_sensor_pin, INPUT);
  Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:
  analog_sensor_value = analogRead(analog_sensor_pin); //read the Voltage of the pin sensor

  Serial.println(analog_sensor_value); // print the value on the Serial monitor
  delay(100);

}

Once I had the values of the sensor (distance in cm)I looked up for a code wich I modified a little bit in order to work how I wanted ultrasonic sensor. I took the code from David Portilla

Utrasonic sensor Code

const int Trigger = 2;   //Pin digital 2 para el Trigger del sensor
const int Echo = 3;   //Pin digital 3 para el Echo del sensor
int led = 6;           // the PWM pin the LED is attached to
int brightness = 0;    // how bright the LED is
int fadeAmount = 12;    // how many points to fade the LED by

void setup() {
  Serial.begin(9600);//iniciailzamos la comunicación
  pinMode(6, OUTPUT); //pin como salida
  pinMode(Echo, INPUT);  //pin como entrada
  digitalWrite(Trigger, LOW);//Inicializamos el pin con 0
  pinMode(Trigger, OUTPUT); // Sets the trigPin as an OUTPUT
  pinMode(Echo, INPUT); // Sets the echoPin as an INPUT
  digitalWrite(Trigger, LOW);
}

void loop() {

  long t; //timepo que demora en llegar el eco
  long d; //distancia en centimetros

  digitalWrite(Trigger, HIGH);
  delayMicroseconds(10);          //Enviamos un pulso de 10us
  digitalWrite(Trigger, LOW);

  t = pulseIn(Echo, HIGH); //obtenemos el ancho del pulso
  d = t/59;             //escalamos el tiempo a una distancia en cm

  Serial.print("Distancia: ");
  Serial.print(d);      //Enviamos serialmente el valor de la distancia
  Serial.print("cm");
  Serial.println();


  if (d < 5){
    analogWrite(led, brightness);


  brightness = brightness + fadeAmount;
   if (brightness <=0 || brightness >=255) {
    fadeAmount = -fadeAmount;
   }
   }else{
    digitalWrite(led, LOW);
   }
  }

𖦹 Notes & thoughs 𖦹¶

I want to keep on experimenting with soft sensor and Arduino