BLU - a Wearable Sensor/status Bracelet

This project was undertaken as I was applying for Intel's "Make it Wearable" contest (https://makeit.intel.com/).

Trailer of that contest:

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Although I did not win I decided to try to build my idea. While the idea is not so simple here it is summarized [also see video]: a wearable device that has embedded sensors to monitor your environment and give you feedback/information on certain parameters and most prominently the quality of air and water.

This is only step one: designing a simple bracelet that displays the status of anything with embedded LEDs in a nice light diffusing 3D printed casing. Hopefully later down the road I'll be able to achieve the final goal as described in the BLU video.

The original design is the white 3D printed bracelet - it was too fragile and turned out quite ugly...

The second try; a much simpler design worked quite well. Simple arcs with a hollow portion in the middle. There is the main body and the cover. The design is very solid, and diffuses the light. It may not look super classy - but it ain't too bad either!

To have a nice and diffused light I utilized a few different tricks:

1. I used Suguru (http://www.adafruit.com/products/436). A little dab of white suguru on each LED and the light was much "softer".
2. I put a layer of white paper inside the walls of the bracelet and transparent (opaque) tape on the paper.

The electronics are very simple:

- Arduino Gemma ( http://www.adafruit.com/gemma ) [although any mini Arduino will do!]

- Lithium cell battery

- 3 or more Neopixels (http://www.adafruit.com/products/1260)

And they all nicely fit into the casing!

For the battery, any battery should do... but I have a preference for lithium as they are small, hold a decent charge, are easy to get and have the ability to be recharged.

Here is code I wrote for it. It's pretty strait-forward and simple.

1. It uses the following Arduino library: https://github.com/adafruit/Adafruit_NeoPixel
2. For a lot of tutorials and further tips on Neo-pixels, this page is quite useful: https://learn.adafruit.com/adafruit-neopixel-uberg...

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#include

//requires library from https://github.com/adafruit/Adafruit_NeoPixel

//arbitrary PIN for now

#define PIN 2

#define WAIT 20 //milliseconds off time between next color

#define SEQLEN 5 //memory of array = how many colors?

#define SEC 1000 //millis in a second

#define NUMPIXELS 10

#define PI 3.14159

// Parameter 1 = number of pixels in strip

// Parameter 2 = Arduino pin number (most are valid)

// Parameter 3 = pixel type flags, add together as needed:

// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)

// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)

// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)

// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)

Adafruit_NeoPixel light = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

//color sequence

//define each element using light.Color(R,G,B) function.

uint32_t WHITE = light.Color(255,255,255);

uint32_t RED = light.Color(255,0,0);

uint32_t GREEN = light.Color(0, 255,0);

uint32_t BLUE = light.Color(0,0,255);

uint32_t YELLOW = light.Color(255,215,0);

uint32_t colors[SEQLEN] = {

WHITE, RED, YELLOW, GREEN, BLUE};

//how long each color.

uint32_t colortime[SEQLEN] = {

10*SEC, 6*SEC, 6*SEC, 6*SEC, 6*SEC};

unsigned long t0 = 0;

void setup(){

Serial.begin(9600);

/* colors[0] = WHITE;

colors[1] = RED;

colors[2] = YELLOW;

colors[3] = GREEN;

colors[4] = BLUE;

*/

light.begin();

light.show();

}

void loop(){

for(int bulb = 0; bulb < SEQLEN; ++bulb){

Serial.println("Setting new bulb");

Serial.print(colors[bulb]);

Serial.print("\t");

Serial.println(colortime[bulb]);

t0 = millis();

delay(1);

unsigned long t = millis()-t0;

while(colortime[bulb] - t*1. > 0){

light.setBrightness(int(255*sin(PI*t/colortime[bulb])));

for(int pixel = 0; pixel < NUMPIXELS; ++pixel){

light.setPixelColor(pixel, colors[bulb] );

}

delay(10);

t = millis()-t0;

Serial.println(colortime[bulb] - t*1.);

light.show();

}

// delay(colortime[bulb]);

#if WAIT

for(int pixel = 0; pixel < NUMPIXELS; ++pixel){

light.setPixelColor(0,0);

}

light.show();

delay(WAIT);

#endif

}

}

Later down the road as time and funds become available I'm going to add Bluetooth (perhaps with one of these? http://www.adafruit.com/products/1697).

And then comes the tricky part: the sensors! But in the mean time it looks wicked cool :) ! [see video]

Tips and ideas are welcome!