13. Skin Electronics¶
Materials¶
| Qty | Description | Price | Link | Notes |
|---|---|---|---|---|
| 1 | Adafruit Gemma M0 | $ 9.95 | https://www.adafruit.com/product/3501 | |
| 2 | Adafruit Neopixels Flora RGB Smart Neopixel - Pack of 4 | $ 7.95 | https://www.adafruit.com/product/1260 | This project uses 5 pixels |
| 1 | Lithium Ion Polymer Battery | $ 6.95 | https://www.adafruit.com/product/1370 | 3.7V 150mAh |
| 1 | Enameled copper wire | $ 11.70 | https://www.amazon.com/gp/product/B00UWCXRK6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 | |
| 1 | Ecoflex 00-30 - Super-Soft, Cure Silicone Rubber | $ 36.47 | https://www.amazon.com/gp/product/B00CA5VY3U/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 | |
| 1 | Felt scrap from previous project | $ 0.00 | Recycle a scrap from somewhere else! :) | |
| 1 | Hair clip | $ 0.00 | I recycled this from a wig |
Code¶
I got the code from a capacitive touch pendant project on the Adafruit Blog. This code uses the Gemma M0s capacitive touch ability to shift the color of the LEDs when touched.
// SPDX-FileCopyrightText: 2018 Erin St. Blaine for Adafruit Industries
//
// SPDX-License-Identifier: MIT
// Code by Erin St. Blaine for Adafruit Industries
// Color Touch Pendant Tutorial: https://learn.adafruit.com/color-touch-pendant-necklace/introduction
// Two neopixel rings connected on pin 1 will cycle through gradient colors when the pendant is touched. For Gemma M0.
#include "Adafruit_FreeTouch.h"
#include "FastLED.h"
#define CAPTOUCH_PIN 0 //capacitive touch pin
#define NEOPIXEL_PIN 1 //neopixel pin
#define NUM_LEDS 5 //how many pixels total
#define LED_TYPE WS2812
#define COLOR_ORDER GRB
CRGB leds[NUM_LEDS]; //LED array
// These variables will affect the way the gradient animation looks. Feel free to mess with them.
int SPEEDO = 20;
int STEPS = 50;
int HUE = 0;
int SATURATION = 255;
int COLORCHANGE = 100;
int BRIGHTNESS = 120;
// Calibrating your capacitive touch sensitivity: Change this variable to something between your capacitive touch serial readouts for on and off
int touch = 700;
long oldState = 0;
// set up capacitive touch button using the FreeTouch library
Adafruit_FreeTouch qt_1 = Adafruit_FreeTouch(CAPTOUCH_PIN, OVERSAMPLE_4, RESISTOR_50K, FREQ_MODE_NONE);
TBlendType currentBlending;
CRGBPalette16 currentPalette;
void setup() {
Serial.begin(115200);
if (! qt_1.begin())
Serial.println("Failed to begin qt on pin A1");
FastLED.addLeds<WS2812, NEOPIXEL_PIN, COLOR_ORDER>(leds, NUM_LEDS); // Set up neopixels with FastLED
FastLED.setBrightness(BRIGHTNESS); // set global brightness
FastLED.setMaxPowerInVoltsAndMilliamps(3,350); //Constrain FastLED's power usage
}
void loop() {
Serial.print(qt_1.measure());
Serial.write(' ');
checkpress(); //check to see if the button's been pressed
//delay(20);
}
void checkpress() {
// Get current button state.
long newState = qt_1.measure();
Serial.println(qt_1.measure());
if (newState > touch && oldState < touch) {
// Short delay to debounce button.
delay(500);
// Check if button is still low after debounce.
long newState = qt_1.measure(); }
if (newState > touch ) {
HUE=HUE+COLORCHANGE; // change the hue by a specified amount each time the cap touch pad is activated
if (HUE > 255){
HUE=0;}
Gradient();
}
// if (HUE==250) {
// dark();
// }
else {
Gradient();
}
// Set the last button state to the old state.
oldState = newState;
}
// GRADIENT --------------------------------------------------------------
void Gradient()
{
SetupGradientPalette();
static uint8_t startIndex = 0;
startIndex = startIndex - 1; // motion speed
FillLEDsFromPaletteColors( startIndex);
FastLED.show();
FastLED.delay(SPEEDO);
}
// adjust hue, saturation and brightness values here to make a pleasing gradient
void SetupGradientPalette()
{
CRGB light = CHSV( HUE + 25, SATURATION - 20, BRIGHTNESS);
CRGB lightmed = CHSV (HUE + 15, SATURATION - 10, BRIGHTNESS-50);
CRGB medium = CHSV ( HUE + 10, SATURATION - 15, BRIGHTNESS);
CRGB dark = CHSV( HUE, SATURATION, BRIGHTNESS);
CRGB black = CHSV (HUE, SATURATION, 0);
currentPalette = CRGBPalette16(
black, light, light, light,
lightmed, lightmed, lightmed, medium,
medium, medium, medium, dark,
dark, dark, dark, black );
}
void FillLEDsFromPaletteColors( uint8_t colorIndex)
{
uint8_t brightness = BRIGHTNESS;
for( int i = 0; i < NUM_LEDS; i++) {
leds[i] = ColorFromPalette( currentPalette, colorIndex, brightness, currentBlending);
colorIndex += STEPS;
}
}
void dark()
{
for(int i = 0; i < NUM_LEDS; i++) {
leds[i] = CRGB::Black;
FastLED.show();
delay(20);
}
}
Assembly¶
For this project I made a silicone prosthetic with embedded LEDs that fit on one side of the face. To start I poured a thin base layer of silicone on a piece of wax paper. Once it cured I placed it on my face to trace the rough shape of the prosthetic. I cut out the silicone and returned it to the wax paper. Then I soldered five RGB LED Neopixels together with enameled copper wire. I also added a strip of copper (sanded bare of enamel) to use as a button. The LEDs were placed in the silicone base layer and temporarily glued in place. I poured a few more thin layers of silicone over the LEDs and led each cure in between. For the last layer I added crushed gold leaf.
After the last layer cured I soldered the LED strip to the GEMMA microcontroller. I also sondered the “button” to one of the capacitive touch pins. I loaded the code and tested the speed and animation variables to get the look I wanted. Lastly I sewed a little felt case for a battery and microcontroller that could be placed in my hair with a clip. The silicone piece was applied to the face with prosthetic glue.