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.

Step 1: The Casing

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!

Step 2: Light Diffusion

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.

Step 3: The Electronics

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.

Step 4: The Code

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

}

}

Step 5: Results & Further Additions

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!