Pulse Sensor
Introduction:
Pulse sensor is a well designed Plug and Play sensor through which user can take live heart rate or pulse rate data and can feed it wherever it wants.
The heartbeat sensor is based on the principle of photophlethysmography i.e. Heart Beat can be measured based on optical power variation as light is scattered or absorbed during its path through the blood as the heart beat changes. This means that the sensor measures the change in volume of blood through any organ of the body which causes a change in the light intensity through that organ. The flow of blood volume is decided by the rate of heart pulses and since light is absorbed by blood, the signal pulses are equivalent to the heart beat pulses.
There are two types of Photophlethysmography:
Transmission: Light emitted from the light emitting device is transmitted through any vascular region of the body like earlobe and received by the detector.
Reflection: Light emitted from the light emitting device is reflected by the regions.
Usage:
Pulse Sensor can be used in the places where live pulse rates are needed. Some common examples are 3D Gaming, Athletics, Smart Phones etc.
Application:
Project for Reference:
Connection:
GND of Arduino – GND Sensor
VCC Arduino – VCC Sensor
A0 Arduino – Signal pin of Sensor
Code:
/* Pulse Sensor Amped 1.5 by Joel Murphy and Yury Gitman http://www.pulsesensor.com
---------------------- Notes ---------------------- ----------------------
This code:
1) Blinks an LED to User's Live Heartbeat PIN 13
2) Fades an LED to User's Live HeartBeat PIN 5
3) Determines BPM
4) Prints All of the Above to Serial
Read Me:
https://github.com/WorldFamousElectronics/PulseSensor_Amped_Arduino/blob/master/README.md
---------------------- ---------------------- ----------------------
*/
#define PROCESSING_VISUALIZER 1
#define SERIAL_PLOTTER 2
// Variables
int pulsePin = 0; // Pulse Sensor purple wire connected to analog pin 0
int blinkPin = 13; // pin to blink led at each beat
int fadePin = 5; // pin to do fancy classy fading blink at each beat
int fadeRate = 0; // used to fade LED on with PWM on fadePin
// Volatile Variables, used in the interrupt service routine!
volatile int BPM; // int that holds raw Analog in 0. updated every 2mS
volatile int Signal; // holds the incoming raw data
volatile int IBI = 600; // int that holds the time interval between beats! Must be seeded!
volatile boolean Pulse = false; // "True" when User's live heartbeat is detected. "False" when not a "live beat".
volatile boolean QS = false; // becomes true when Arduoino finds a beat.
// SET THE SERIAL OUTPUT TYPE TO YOUR NEEDS
// PROCESSING_VISUALIZER works with Pulse Sensor Processing Visualizer
// https://github.com/WorldFamousElectronics/PulseSensor_Amped_Processing_Visualizer
// SERIAL_PLOTTER outputs sensor data for viewing with the Arduino Serial Plotter
// run the Serial Plotter at 115200 baud: Tools/Serial Plotter or Command+L
static int outputType = SERIAL_PLOTTER;
void setup(){
pinMode(blinkPin,OUTPUT); // pin that will blink to your heartbeat!
pinMode(fadePin,OUTPUT); // pin that will fade to your heartbeat!
Serial.begin(115200); // we agree to talk fast!
interruptSetup(); // sets up to read Pulse Sensor signal every 2mS
// IF YOU ARE POWERING The Pulse Sensor AT VOLTAGE LESS THAN THE BOARD VOLTAGE,
// UN-COMMENT THE NEXT LINE AND APPLY THAT VOLTAGE TO THE A-REF PIN
// analogReference(EXTERNAL);
}
// Where the Magic Happens
void loop(){
serialOutput() ;
if (QS == true){ // A Heartbeat Was Found
// BPM and IBI have been Determined
// Quantified Self "QS" true when arduino finds a heartbeat
fadeRate = 255; // Makes the LED Fade Effect Happen
// Set 'fadeRate' Variable to 255 to fade LED with pulse
serialOutputWhenBeatHappens(); // A Beat Happened, Output that to serial.
QS = false; // reset the Quantified Self flag for next time
}
ledFadeToBeat(); // Makes the LED Fade Effect Happen
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!
analogWrite(fadePin,fadeRate); // fade LED
}
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