pulse sensor

i'm just asking, on how to set the lcd to clear screen whenever there is no pulse detected.. thank you for response...

Send an LCD clear command, or write all spaces to the LCD.

AWOL: Send an LCD clear command, or write all spaces to the LCD.

.... assuming you've already figured out how to detect the lack of pulse. If you haven't, and need help with that part, then you will need to post the code you already have to detect the pulse.

this is my code…
even when there is no fingertip in pulse sensor…
the lcd displays the last pulse rate…

       #include <LiquidCrystal.h>


/*
>> Pulse Sensor Amped 1.2 <<
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 1.2 by Joel Murphy & Yury Gitman  Spring 2013
This update fixes the firstBeat and secondBeat flag usage so that realistic BPM is reported.

*/

LiquidCrystal lcd(12, 11, 5, 4, 3, 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 = 6;                  // pin to do fancy classy fading blink at each beat
int fadeRate = 0;                 // used to fade LED on with PWM on fadePin
int age = 20;

// 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, must be seeded! 
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.

//LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
#include <Wtv020sd16p.h>
int resetPin = 7;  // The pin number of the reset pin.
int clockPin = 8;  // The pin number of the clock pin.
int dataPin = 9;  // The pin number of the data pin.
int busyPin = 10;  // The pin number of the busy pin.

Wtv020sd16p wtv020sd16p(resetPin,clockPin,dataPin,busyPin);

void setup(){
wtv020sd16p.reset();
  pinMode(blinkPin,OUTPUT);         // pin that will blink to your heartbeat!
  pinMode(fadePin,OUTPUT);          // pin that will fade to your heartbeat!
 lcd.begin(16, 2);                 // we agree to talk fast!
   Serial.begin(115200);  
   
  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
        sendDataToProcessing('Q',IBI);   // send time between beats with a 'Q' prefix
        QS = false;                      // reset the Quantified Self flag for next time    
        lcd.clear();
      lcd.setCursor(0,0);
    lcd.print("Heart Rate: ");
    lcd.print (BPM);  
  }
   if (age <= 2 && BPM >= 130)
      {
        lcd.setCursor(0,1);
        lcd.print("High Heartbeat");
        wtv020sd16p.asyncPlayVoice(1);
       
}
        else if (age <= 2 && BPM < 80)
        {
        lcd.setCursor(0,1);
        lcd.print("Low Heartbeat");
        wtv020sd16p.asyncPlayVoice(2);
      
   }
   else if (age <= 2 && BPM <= 130)
   {
        lcd.setCursor(0,1);
        lcd.print("Normal Heartbeat");
     
   }
   else if (age <= 4 && BPM < 80)
      {
        lcd.setCursor(0,1);
        lcd.print("Low Heartbeat");
        wtv020sd16p.asyncPlayVoice(2);
      
}
        else if (age <= 4 && BPM > 120)
        {
        lcd.setCursor(0,1);
        lcd.print("High Heartbeat");
        wtv020sd16p.asyncPlayVoice(1);
       
   }
   else if (age <= 4 && BPM <= 120)
   {
        lcd.setCursor(0,1);
        lcd.print("Normal Heartbeat");
        
   }
   else if (age <= 6 && BPM < 75)
      {
        lcd.setCursor(0,1);
        lcd.print("Low Heartbeat");
        wtv020sd16p.asyncPlayVoice(2);
       
}
        else if (age <= 6 && BPM > 115)
        {
        lcd.setCursor(0,1);
        lcd.print("High Heartbeat");
        wtv020sd16p.asyncPlayVoice(1);
     
   }
   else if (age <= 6 && BPM <= 115)
   {
        lcd.setCursor(0,1);
        lcd.print("Normal Heartbeat");
        
   }
   else if (age <= 9 && BPM < 70)
      {
        lcd.setCursor(0,1);
        lcd.print("Low Heartbeat");
        wtv020sd16p.asyncPlayVoice(2);
         
}
        else if (age <= 9 && BPM > 110)
        {
        lcd.setCursor(0,1);
        lcd.print("High Heartbeat");
        wtv020sd16p.asyncPlayVoice(1);
       
   }
   else if (age <= 9 && BPM <= 110)
   {
        lcd.setCursor(0,1);
        lcd.print("Normal Heartbeat");
    
   }
   else if(age >=10 && BPM < 60)
      {
        lcd.setCursor(0,1);
        lcd.print("Low Heartbeat");
        wtv020sd16p.asyncPlayVoice(2);

}
        else if (age >= 10 && BPM > 100)
        {
        lcd.setCursor(0,1);
        lcd.print("High Heartbeat");
        wtv020sd16p.asyncPlayVoice(1);
   
   }
   else if (age >= 10 && BPM <= 100)
   {
        lcd.setCursor(0,1);
        lcd.print("Normal Heartbeat");
    
   }
  
   
  ledFadeToBeat();  
  delay(20);                             //  take a break
      
 /* if (QS == false){
  lcd.clear();
  }  */
   if (BPM<50){
  lcd.clear();
  }

   }

   
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
}

Moderator: Please, can someone tell me why CODE TAGS are so difficult to understand?

//  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 = 6;                  // pin to do fancy classy fading blink at each beat
int fadeRate = 0;                 // used to fade LED on with PWM on fadePin
int age = 20;

Misleading comment - they are variables, I agree, but they shouldn't be.

how to clear the lcd? because, even when the fingertip was remove in pulse sensor.. the lcd displays the previous pulse rate..

Timestamp the last time you had a valid update, and if any time in loop() the difference between the time now and the timestamp exceeds, say, a couple of seconds, clear the LCD.

Maybe there's something in the Wtv020sd16p library that would do it. I don't have that library, so I don't know.

ok..thank you