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Topic: Pulse sensor Amped (Read 5087 times) previous topic - next topic

cute-98

Have someone ever try buying pulse sensor amped (http://pulsesensor.myshopify.com/) , but create own code to read the pulse and print result in serial monitor?
Please share and help me.

Grumpy_Mike

What is wrong with the code on that web site?

cute-98


What is wrong with the code on that web site?


I try the exact code. But LED 13 doesn't blink when i touch it. The processing that shows the heartbeats work, but it only changes every time i touch it, where actually it is said that when we touch it it will continuously detect our heart rate without having to keep removing our fingers.

So I am planing on creating a simple code without using any processing code. And just print the hear rate in the serial monitor. But no luck it doesn't work.:(

Grumpy_Mike

If the standard software does not work what makes you think your own software will work any better. Basically you have a hardware problem.

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The processing that shows the heartbeats work, but it only changes every time i touch it,

No the heart beat does not work if that is what it does.
These sorts of sensors are not as easy to use as you might think. You have to be very still and let the sensor settle down before it produces worthwhile results.

cute-98


If the standard software does not work what makes you think your own software will work any better. Basically you have a hardware problem.

Quote
The processing that shows the heartbeats work, but it only changes every time i touch it,

No the heart beat does not work if that is what it does.
These sorts of sensors are not as easy to use as you might think. You have to be very still and let the sensor settle down before it produces worthwhile results.


So what do u suggest me to do to make it working as it is? I am a beginner and still on a learning mode. So any guide will be much appreciated.

Grumpy_Mike

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So what do u suggest me to do to make it working as it is

Use the standard software how to use and learn how to use the hardware. Play about with it, try and get it to read your pulse. Relax and be still and you will see it start to work.
Something like this is not as robust as you might like it.

cute-98


Use the standard software how to use


Standard software, do you mean just the basic coding using the Arduino interface without the processing?
if that the case, I have tried using the following code:

Code: [Select]

unsigned char pin = 13;
  unsigned char counter=0;
  unsigned int heart_rate=0;
  unsigned long temp[21];
  unsigned long sub=0;
  volatile unsigned char state = LOW;
  bool data_effect=true;
  const int max_heartpluse_duty=2000;//you can change it follow your system's request.2000 meams 2 seconds.
  //System return error if the duty overtrip 2 second.
 
  void setup()
  {
      pinMode(pin, OUTPUT);
      Serial.begin(9600);
      Serial.println("Please ready your eat clip.");
      delay(5000);
      array_init();
      Serial.println("Heart rate test begin.");
      attachInterrupt(1, interrupt, RISING);//set interrupt 0,digital port 2
  }
 
  void loop()
  {
      digitalWrite(pin, state);
  }
 
  void sum()//calculate the heart rate
  {
      if(data_effect)
      {
        heart_rate=120000/(temp[20]-temp[0]);//6*20*1000/20_total_time
        Serial.print("Heart_rate_is:\t");
        Serial.println(heart_rate);
      }
      data_effect=1;//sign bit
  }
 
  void interrupt()
  {
    temp[counter]=millis();
    state = !state;
    Serial.println(counter,DEC);
    Serial.println(temp[counter]);
    switch(counter)
     {
        case(0):
        sub=temp[counter]-temp[20];
        Serial.println(sub);
        break;
        default:
        sub=temp[counter]-temp[counter-1];
        Serial.println(sub);
        break;
      }
    if(sub>max_heartpluse_duty)//set 2 seconds as max heart pluse duty
     {
        data_effect=0;//sign bit
        counter=0;
        Serial.println("Heart rate measure error,test will restart!" );
        array_init();
     }
    if (counter==20&&data_effect)
      {
        counter=0;
        sum();
      }
    else if(counter!=20&&data_effect)
      counter++;
    else
    {
      counter=0;
      data_effect=1;
    }
  }
 
  void array_init()
  {
      for(unsigned char i=0;i!=20;++i)
      {
        temp[i]=0;
      }
      temp[20]=millis();
  }


It's true that I started to panic since my deadline is coming close, and I just get fix with xbee and temperature sensor and now the pulse sensor is just not working though I have follow the tutorial for almost 5 times. I find people posting same problem in the pulsesensor forum itself but no one get a reply for it.

Grumpy_Mike

Do not use print statements in interrupt service routines.

cute-98


Do not use print statements in interrupt service routines.


Can i know why?

JimboZA



Do not use print statements in interrupt service routines.


Can i know why?


The Sparkfun tutorial on interrupts says:

Quote
Be aware though that it is important to keep the interrupt handler as short as possible because it prevents the processor from running its normal code, prevents other interrupts of lower priority, and could be called quite often depending what input you have connected. It's best to just update status variables and then leave, and let your normal program do the rest of the necessary work.


I'd guess that's why....
My hovercraft is full of eels.

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

Grumpy_Mike

That code is not what I downloaded from that site.

cute-98


That code is not what I downloaded from that site.


Yes, It's not. It's from a different source, as the one in the website doesn't work even after  trying several times.

Grumpy_Mike

Quote
It's from a different source,

Well it is rubbish.

Quote
as the one in the website doesn't work even after  trying several times.

Why not?

cute-98


Why not?


Let me just show the connection and screenshots here.

1. I open the "PulseSensorAmped_Arduino_1dot1" in Arduino 1.0.1 ( there is 2 files open "PulseSensorAmped_Arduino_1dot1.ino" and "Interrupt.ino")

The PulseSensorAmped_Arduino_1dot1.ino has the following code:
Code: [Select]


/*
>> Pulse Sensor Amped 1.1 <<
This code is for Pulse Sensor Amped by Joel Murphy and Yury Gitman
    www.pulsesensor.com
    >>> 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.

This code is designed with output serial data to Processing sketch "PulseSensorAmped_Processing-xx"
The Processing sketch is a simple data visualizer.
All the work to find the heartbeat and determine the heartrate happens in the code below.
Pin 13 LED will blink with heartbeat.
If you want to use pin 13 for something else, adjust the interrupt handler
It will also fade an LED on pin fadePin with every beat. Put an LED and series resistor from fadePin to GND.
Check here for detailed code walkthrough:
http://pulsesensor.myshopify.com/pages/pulse-sensor-amped-arduino-v1dot1

Code Version 02 by Joel Murphy & Yury Gitman  Fall 2012
This update changes the HRV variable name to IBI, which stands for Inter-Beat Interval, for clarity.
Switched the interrupt to Timer2.  500Hz sample rate, 2mS resolution IBI value.
Fade LED pin moved to pin 5 (use of Timer2 disables PWM on pins 3 & 11).
Tidied up inefficiencies since the last version.
*/


//  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


// 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.


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
   // UN-COMMENT THE NEXT LINE IF YOU ARE POWERING The Pulse Sensor AT LOW VOLTAGE,
   // AND APPLY THAT VOLTAGE TO THE A-REF PIN
   //analogReference(EXTERNAL);   
}



void loop(){
  sendDataToProcessing('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
        sendDataToProcessing('B',BPM);   // send heart rate with a 'B' prefix
        Serial.print("BPM=");
        Serial.print(BPM);
        sendDataToProcessing('Q',IBI);   // send time between beats with a 'Q' prefix
        QS = false;                      // reset the Quantified Self flag for next time   
     }
 
  ledFadeToBeat();
 
  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
  }


void sendDataToProcessing(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
  }


2. I open the PulseSensorAmpd_Processing_1dot1.pde in processing 1.5.1, it opens 4 files (PulseSensorAmpd_Processing_1dot1.pde, keyboard_mouse.pde, scaleBar.pde and serialEvent.pde)

I upload the arduino code to the pulse sensor board. The pin 13 LED blinks. Then i put my finger on the pulse sensor. The pin 13 LED keep lights up (not blinking), which actually should blink every time it detects the heartbeat.

I include attachment for the connection and result both in processing and serial monitor.

Is there any way I can check whether it is working from the serial monitor?

Grumpy_Mike

Quote
Is there any way I can check whether it is working from the serial monitor?

Yes open the serial monitor and see what is printed there.

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