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5. E-Textiles

I found e-textiles fascinating and magical but very far from me. i started this assignement from scratch since electronics is a completely new world. so i started to know its elements and basics. i don't hide the fact that a small mistake can be the cause of your prototype not working. so you have to be patient and persevere to get rewarding results.

Circuit

Circuit is a path for Electricity to flow move: stream moving electrons create current how the electronsmove: from + to -

  • VOLTAGE (V) is the electrrical force between two points
  • CURRENT (I) speed with which the electronic charge flows
  • RESISTANCE (R) Ohms amount of material thatresist current flow For measuring voltage,current and resistance we need multimeter

Ohms law: V = I x R

  • Electrons are lazy: the electrical energy follows the path of least resistance downwards
  • Electricity hates waste: all electrical energy in the circuit must be used
  • Circuit is a system: different component play different role in the system of circuit

Materials

  • we can use any conductive material any material that allowed the energy to pass
  • Consider different proprieties : resistance, strechiness solderability, feel substrate + productive process.

Sensors

input > information or data that enters the system like a pressed button

  • Digital: is like a switch; immagine is like on/off

  • Analog: range of value, like a spectrum

  • momentary switches > Push the botton only stay open as long as you are pressing the conductive material toghether into contact

  • toggle switches > are similar to momentary switch but they stay open so you don't have to press it.
  • tilt switches > a conductive bead or pom-pom makes contact with the fabric patches based on location

Analog sensors

We can use resistance to get a higher range of values. By passing more current we can change the brightness of an LED, the frequency of a sound or the speed of a motor. Resistance > we can change the resistance in 3 ways

  • 1) Distance: resistance increases with distance regardless of material type
  • 2) contact > some materials are sensitive to pressure and decrease their resistance when pressure is applied
  • 3) surface area > increasing the size of the area where electricity flows decreases resistance

Microcrontollers & Programming

Computers > Different computers are designed to do different things

ARDUINO

  • HARDWARE: electronics physical object
  • SOFTWARE: that we use for control the hardware

HYSICAL COMPUTING : is prototyping with the electronics

Components

  • Boad > Arduino UNO purpose for using Arduino uno: control leds, read sensors, control leds based on interaction with sensors Method to use it: Make a circuit, write circuit code correctly

In the board you can connect input and output devices and connect them to minicontrollers

INPUT/OUTPUT PINS: We use the pins as the Arduino is able to read the voltage (V) through them and also control the volts (V)

Pin PWM: those with the symbol ˜

POWER PINS :

GND > are connected together so you can use whichever one you prefer

5/3.3 V > are always on

  • Breadboard

In the bread board, the holes are connected to each other as can be seen in the picture > both vertically +/- and horizontally.

reasoning in lines and not in holes

5V > +

GRD > -

Arduino sketches

  • File > New

  • Void Setup and Void loop are critical, without them the sketch will not work

  • Void Setup : everything inside brackets {} works once.

  • Void loop : everything put inside brackets {} works repeatedly.

  • Arduino reads the sketch from top to bottom, line by line.

  • Gray words are notes not commands.

  • Written the sketch > Verify > Load the sketch.

  • ARDUINO REFERENCE : is the Arduino vocabulary that tells you functions and commands with examples. it is easily found on Google

  • Digital Write > ON / OFF Led.

  • Analog Write > intensity Led +

Digital Sensor

Simple Switch

To create a simple digital sensor, I cut two rectangles of plain fabric with a piece of fabric inside that was conductive on both sides and ran conductive wire over it; creating a sandwich with a sponge inside with a hole in the middle.

Digital sensor switch

  • We need to create a structure that has a resistor ( no lower than 5k Ω )

  • I followed the diagram above to connect the board to the breadboard and connected the USB cable to the computer.

  • I opened the Sketch given to us by Emma: 03_ read_DigitalSensor

  • Load Sketch

  • Arduino is now reading the circuit in the Serial Monitor.

Serial Monitor(magnifying glass in the upper right corner or tools > Serial Monitor): this is a tool to display the information sent from the Arduino UNO to the Computer. If I press the switch it shows me the number 0 while if I release it it becomes 1

Serial Plotter (Tools > Serial Plotter): is another way to display the information from the Arduino UNO to the Computer but through a graphical representation.

Digital switch +Led

* Disconnect the USB socket when making changes to the circuit.

  • In this case I simply added the led circuit following the diagram

  • I opened the sketch: 04_button_led ( check the sketch matches the circuit created)

  • Check the sketch

  • Plugh Arduino ONE to the Computer.

  • Upload the Sketch

Now when I press the switch the light turns off while if I release it it stays steady.

Analog sensor

Digital Switch

  • Velostat
  • Neoprene
  • Conductive thread

    the way you make your Analog Sensor has a big impact on the functionality of the sensor>(example. when the thread touches the fabric + is your sensor sturdy = more effective) Make the thread position evenly on the fabric, not just partially

Now it is possible to measure with the Multimeter:

  • 6kΩ setting

  • you can measure the resistance

  • upon movement the value changes.

Analog sensor in Arduino

  • We are going to use Analog Pins ( A0, A1, A2....).

  • Resistors: Fix resistor and Variable resistor.

  • Follow the diagram to place the jumper wires.

  • Plug the USB cable

  • Open the 05_readAnalogSensor sketch.

  • Check if the pin definition is correct

  • Verify > Upload the sketch

  • Open the serial monitor or serial plotter: if I press the switch the numbers go down since the voltage changes.

    To display the analog sensor in another graphical way, we can use the SMOOTHING sketch ( Example>Analog>Smoothing).

Load the sketch( remember to check if the pins shown are right).

View Serial potter: You can read how the values vary by pressing the analog sensor (from 0 to 1024).

  • Each Analog Sensor has a different min and max this tool allows us to understand the values

Analog Sensor + Led

  • Follow the diagram to connect Arduino UNO to the Breadboard.

  • Open 07_ Pressure_led

  • Edit the definition of Analog Sensor map.

Map(analog_sensor_value,230,130,0,225) // You can change it

Constrain(analog_sensor_value,0,225) // You cannot change it

  • First find out the maximum and minimum variation of your sensor with the help of the SMOOTHING sketch (example: Min = 150 ; Max = 340 )

  • EXAMPLE:

map(analog_sensor_value,130,230,0,225)

map(analog_sensor_value,150,340,0,225)

Once the sketch is uploaded I can use it by pressing the switch and you will see that it changes light intensity in pressing the switch.

Last update: 2022-08-29