12. Skin Electronics¶

Research¶

Skin electronics explore the integration of soft, flexible, and body-safe electronic components directly onto the skin or close to the body. These systems commonly use temporary tattoo circuits, conductive inks, silicone substrates, flexible PCBs, and wearable sensors. The goal is to create electronics that feel natural, stretch with the skin, and provide interaction without traditional rigid hardware.

They are used in applications such as:

Health monitoring (heart rate, hydration, movement sensors)

Interactive performance (light-reactive tattoos, gesture control)

Fashion and body art

Soft robotics and prosthetics

Researchers in this field focus on material softness, biocompatibility, sensor accuracy, and user comfort. Different fabrication techniques include screen-printing conductive inks, laser cutting circuits, vinyl cutting, flexible microcontrollers, and temporary tattoo substrates.

Skin electronics push the boundaries of how technology blends into daily life, enhancing personal expression, healthcare, and interactivity.

References & Inspiration¶

Tools AND workflow¶

🧩 1. Materials & Components¶

🔌 Electronics
Seeed Studio XIAO ESP32-C3
× RGB LEDs (4-pin, common cathode)
9 × resistors (220Ω–330Ω)
wires
🔋 Power Supply
USB cable (5V)
Cumputer
RGB LED (4-pin)

NOTE: Each RGB LED contains:

Red channel Green channel Blue channel Common pin (long leg)

👉 The long leg = COMMON (connected to GND for this project)

Resistors

Each color channel requires a resistor:

Prevents LED damage Controls current flow

Total resistors:

3 LEDs × 3 colors = 9 resistors Microcontroller

The Seeed Studio XIAO ESP32-C3 controls the LED using PWM (Pulse Width Modulation), allowing smooth color mixing.

2. System Architecture¶

Input¶

No input (autonomous system) (Expandable with sensors)

utput¶

RGB LEDs (light-based feedback) Processing Microcontroller generates PWM signals

3 Circuit Design¶

Function	XIAO Pin
Red	GPIO3
Green	GPIO4
Blue	GPIO5
GND	GND

All LEDs share the same control pins:

All Red pins → GPIO3 (via resistors)

All Green pins → GPIO4 (via resistors)

All Blue pins → GPIO5 (via resistors)

All Common pins (long legs) → GND

Full Circuit Diagram

            GPIO3
              │
    ┌─────────┼─────────┐
    │         │         │
 [220Ω]    [220Ω]    [220Ω]
    │         │         │
  LED1 R    LED2 R    LED3 R

            GPIO4
              │
    ┌─────────┼─────────┐
    │         │         │
 [220Ω]    [220Ω]    [220Ω]
    │         │         │
  LED1 G    LED2 G    LED3 G

            GPIO5
              │
    ┌─────────┼─────────┐
    │         │         │
 [220Ω]    [220Ω]    [220Ω]
    │         │         │
  LED1 B    LED2 B    LED3 B

All LED COMMON (long legs) ─────────── GND

💻 7. Programming Software Arduino IDE ESP32 board package installed

Code Explanation PWM channels control brightness Colors are mixed using RGB values Loop cycles through color patterns

int redPin = 3;
int greenPin = 4;
int bluePin = 5;

void setup() {
  ledcAttachPin(redPin, 0);
  ledcAttachPin(greenPin, 1);
  ledcAttachPin(bluePin, 2);

  ledcSetup(0, 5000, 8);
  ledcSetup(1, 5000, 8);
  ledcSetup(2, 5000, 8);
}

void setColor(int r, int g, int b) {
  ledcWrite(0, r);
  ledcWrite(1, g);
  ledcWrite(2, b);
}

void loop() {
  // Primary colors
  setColor(255, 0, 0); delay(500);
  setColor(0, 255, 0); delay(500);
  setColor(0, 0, 255); delay(500);

  // Secondary colors
  setColor(255, 255, 0); delay(500);
  setColor(255, 0, 255); delay(500);
  setColor(0, 255, 255); delay(500);

  // White
  setColor(255, 255, 255); delay(500);
}


<## Results
All 3 RGB LEDs function correctly
Smooth color transitions achieved
System stable under continuous operation>










  
    
  
  


  
    
      
  
    
      
    
    2026-05-01