Introduction: Fiber Optic Head Piece

Make a head piece that can transmit light and color based on your pulse!

Step 1: Materials

Arduino Uno R3

Pulse Sensor

Flora RGB Smart NeoPixel

Fiber Optics

9V Battery Clip

Heat Shrink

Metal Wire




Hot Glue

Super Glue

Step 2: Code Your Arduino


This code uses the Pulse Sensor Amped by Joel Murphy and Yury Gitman >>> Pulse Sensor purple wire goes to Analog Pin 0 <<< Pulse Sensor sample aquisition and processing happens in the background via Timer 2 interrupt. 2mS sample rate. PWM on pins 3 and 11 will not work when using this code, because we are using Timer 2! The following variables are automatically updated: Signal : int that holds the analog signal data straight from the sensor. updated every 2mS. IBI : int that holds the time interval between beats. 2mS resolution. BPM : int that holds the heart rate value, derived every beat, from averaging previous 10 IBI values. QS : boolean that is made true whenever Pulse is found and BPM is updated. User must reset. Pulse : boolean that is true when a heartbeat is sensed then false in time with pin13 LED going out.

NOTE: This code works with Arduino UNO or Arduino PRO or Arduino Pro Mini 5V or any Arduino running with an ATmega328 and 16MHz clock. This will disable PWM output on pin 3 and 11. Also, it will disable the tone() command.

All the work to find the heartbeat and determine the heartrate happens in the code below. For using the Pulse Sensor code, see the link below for a code walkthrough:

Code Version 02 by Joel Murphy & Yury Gitman Fall 2012 */

volatile int rate[10]; // used to hold last ten IBI values volatile unsigned long sampleCounter = 0; // used to determine pulse timing volatile unsigned long lastBeatTime = 0; // used to find the inter beat interval volatile int P =512; // used to find peak in pulse wave volatile int T = 512; // used to find trough in pulse wave volatile int thresh = 512; // used to find instant moment of heart beat volatile int amp = 100; // used to hold amplitude of pulse waveform volatile boolean firstBeat = true; // used to seed rate array so we startup with reasonable BPM volatile boolean secondBeat = true; // used to seed rate array so we startup with reasonable BPM


// THIS IS THE TIMER 2 INTERRUPT SERVICE ROUTINE. // Timer 2 makes sure that we take a reading every 2 miliseconds ISR(TIMER2_COMPA_vect){ // triggered when Timer2 counts to 124 cli(); // disable interrupts while we do this Signal = analogRead(pulsePin); // read the Pulse Sensor sampleCounter += 2; // keep track of the time in mS with this variable int N = sampleCounter - lastBeatTime; // monitor the time since the last beat to avoid noise

// find the peak and trough of the pulse wave if(Signal < thresh && N > (IBI/5)*3){ // avoid dichrotic noise by waiting 3/5 of last IBI if (Signal < T){ // T is the trough T = Signal; // keep track of lowest point in pulse wave } } if(Signal > thresh && Signal > P){ // thresh condition helps avoid noise P = Signal; // P is the peak } // keep track of highest point in pulse wave // NOW IT'S TIME TO LOOK FOR THE HEART BEAT // signal surges up in value every time there is a pulse if (N > 250){ // avoid high frequency noise if ( (Signal > thresh) && (Pulse == false) && (N > (IBI/5)*3) ){ Pulse = true; // set the Pulse flag when we think there is a pulse digitalWrite(blinkPin,HIGH); // turn on pin 13 LED IBI = sampleCounter - lastBeatTime; // measure time between beats in mS lastBeatTime = sampleCounter; // keep track of time for next pulse if(firstBeat){ // if it's the first time we found a beat, if firstBeat == TRUE firstBeat = false; // clear firstBeat flag return; // IBI value is unreliable so discard it } if(secondBeat){ // if this is the second beat, if secondBeat == TRUE secondBeat = false; // clear secondBeat flag for(int i=0; i<=9; i++){ // seed the running total to get a realisitic BPM at startup rate[i] = IBI; } } // keep a running total of the last 10 IBI values word runningTotal = 0; // clear the runningTotal variable

for(int i=0; i<=8; i++){ // shift data in the rate array rate[i] = rate[i+1]; // and drop the oldest IBI value runningTotal += rate[i]; // add up the 9 oldest IBI values } rate[9] = IBI; // add the latest IBI to the rate array runningTotal += rate[9]; // add the latest IBI to runningTotal runningTotal /= 10; // average the last 10 IBI values BPM = 60000/runningTotal; // how many beats can fit into a minute? that's BPM! QS = true; // set Quantified Self flag // QS FLAG IS NOT CLEARED INSIDE THIS ISR } }

if (Signal < thresh && Pulse == true){ // when the values are going down, the beat is over digitalWrite(blinkPin,LOW); // turn off pin 13 LED Pulse = false; // reset the Pulse flag so we can do it again amp = P - T; // get amplitude of the pulse wave thresh = amp/2 + T; // set thresh at 50% of the amplitude P = thresh; // reset these for next time T = thresh; } if (N > 2500){ // if 2.5 seconds go by without a beat thresh = 512; // set thresh default P = 512; // set P default T = 512; // set T default lastBeatTime = sampleCounter; // bring the lastBeatTime up to date firstBeat = true; // set these to avoid noise secondBeat = true; // when we get the heartbeat back } sei(); // enable interrupts when youre done! }// end isr

Pulse Sensor

#include // Library containing
// Behavior setting variables int pulsePin = 0; // Pulse Sensor purple wire connected to analog pin 0 int blinkPin = 13; // Digital pin to blink led at each beat int fadePin = 5; // pin to do fancy neopixel effects at each beat int fadeRate = 0; // used to fade LED on with PWM on fadePin // these variables are volatile because they are used during the interrupt service routine volatile int BPM; // used to hold the pulse rate volatile int Signal; // holds the incoming raw data volatile int IBI = 600; // holds the time between beats, the Inter-Beat Interval volatile boolean Pulse = false; // true when pulse wave is high, false when it's low volatile boolean QS = false; // becomes true when Arduoino finds a beat. // Set up use of NeoPixels const int NUMPIXELS = 12; // Put the number of NeoPixels you are using here const int BRIGHTNESS = 255; // Set brightness of NeoPixels here Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMPIXELS, fadePin, NEO_GRB + NEO_KHZ800); void setup(){ pinMode(blinkPin,OUTPUT); // pin that will blink to your heartbeat! // Serial.begin(115200); // Serial output data for debugging or external use strip.begin(); strip.setBrightness(BRIGHTNESS); for (int x=0; x < NUMPIXELS; x++) { // Initialize all pixels to 'off' strip.setPixelColor(x, strip.Color(0, 0, 0)); }; // Ensure the pixels are off delay(1000); // Wait a second interruptSetup(); // sets up to read Pulse Sensor signal every 2mS } void loop(){ // sendDataSerial('S', Signal); // send Processing the raw Pulse Sensor data if (QS == true){ // Quantified Self flag is true when arduino finds a heartbeat fadeRate = 255; // Set 'fadeRate' Variable to 255 to fade LED with pulse // sendDataSerial('B',BPM); // send heart rate with a 'B' prefix // sendDataSerial('Q',IBI); // send time between beats with a 'Q' prefix QS = false; // reset the Quantified Self flag for next time } ledFadeToBeat(); // Routine that fades color intensity to the beat delay(20); // take a break } void ledFadeToBeat() { fadeRate -= 15; // Set LED fade value fadeRate = constrain(fadeRate,0,255); // Keep LED fade value from going into negative numbers setStrip(fadeRate); // Write the value to the NeoPixels // sendDataSerial('R',fadeRate); } void sendDataSerial(char symbol, int data ) { // Serial.print(symbol); // symbol prefix tells Processing what type of data is coming // Serial.println(data); // the data to send culminating in a carriage return } void setStrip(int r) { // Set the strip to one color intensity (red) if (BPM >= 0 && BPM <= 50) { int g=0; int b=r; int r=0; for (int x=0; x < NUMPIXELS; x++) { strip.setPixelColor(x, strip.Color(r, g, b)); }; } else if(BPM >=51 && BPM <= 100) { int g=r; int b=0; int r=0; for (int x=0; x < NUMPIXELS; x++) { strip.setPixelColor(x, strip.Color(r, g, b)); }; } else { int g = 0; // Green is set to zero (for non-red colors, change this) int b = 0; // Blue is set to zero (for non-red colors, change this) for (int x=0; x < NUMPIXELS; x++) { strip.setPixelColor(x, strip.Color(r, g, b)); }; } }

Step 3: Construction

  1. After coding your Arduino, soldier wires from LED and Pulse Sensor to Arduino based on input and output.
  2. Once connected, begin connection of Fiber Optics to LED using super glue.
  3. Fiber Optics should be held in heat shrunk tubing, shrunk by a blow dryer.
  4. Hot glue will be used as an eliminator and light conductor through your design.
  5. Place Fiber Optics with hot glue throughout your head piece.
  6. Attach your Arduino and Pulse Sensor with wire on the head piece.
  7. Hide electronics as best as possible.
  8. Pulse Sensor will read your pulse, and change color based on given code.
  9. Fiber Optics will reflect off LED and light up head piece.
  10. Make sure all wires and fibers are fully attached.