12. Skin Electronics

Research

For this week, I wanted to reuse the same heater circuit that I made during the wearable week with the thermocromic ink.

References & Inspiration

I had a specific idea and I don't really have inspiraions or references to share but your can go see the WEARABLES week were I shared differentes there uses of the thermocromic ink.

Here is the idea, visualisation thanks to pinterest and the prompts "white roots hair" and "old persons".

Tools

- Arduino UNO
- Arduino IDE
- Human hair extensions
- clips
- Silver yarns
- sewing conductive thread
- mofset circuit elements*

↓↓↓ Mofset circuit elements ↓↓↓ + Arduino UNO + Arduino IDE + Personnal Mosfet (transistor) + 9V battery (secondary power source) + 100k resistance + 1N4001 DIODE + Heating element

" Heating takes a LOT of power - current to be specific. Arduino pins cannot provide the power we need to warm a heating element. We can't draw more than 40mA from a pin. We have to construct a circuit that will let us use a secondary power source. Thanks to transistors, we can do this "

Constructed thanks to the Liza Stark's →slide←

What I planed (final circuit)↓↓↓

G : Gate D : Drain S : Source

Process and workflow

STEP 1 : Dying the hair extension

STEP 2 : Sewing test and ohm test

STEP 3 : Build the hair circuit

I found out that the circuit I followed first for the hair circuit had a mystake.

STEP 4 : Re-Build the hair circuit

The correct plan circuit ↓

For now the circuit doesn't work. The most difficult part is to create greats connections without short cut and find the precise resistance for the heating element.

Code

This is a code that handle one transistor. As I wanted to make a circuit with two separate heating element, here is not the finall circuit.

→ Blink code

void setup() {

  pinMode(3, OUTPUT);
}

{
  digitalWrite(3, HIGH);
  delay(10000);
  digitalWrite(3, LOW);
  delay(2000);
}

New code ?

void setup() {

  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
}

{
  digitalWrite(3, HIGH);
  delay(100000);
  digitalWrite(3, LOW);
  delay(2000); 

  digitalWrite(4, HIGH);
  delay(100000);
  digitalWrite(4, LOW);
  delay(2000);
}