Code error causing me to lose Arduino (Micro) boards (when uploading code)

I have just lost my 3rd arduino (micro) and was hoping someone can help me stop wasting my money. I am a beginner but Im almost certain the error lies within the code. I lose the board as soon as i upload the code involving the pulse sensor. I am attempting to add a pulse sensor to my existing code which is for a 16x2 display and temp sensor…

THE 16x2 display and temp sensor code are working fine. I have provided the code here:

int sensorPin = A0;
// included the library code:
#include <Adafruit_CharacterOLED.h>
Adafruit_CharacterOLED lcd(OLED_V2, 4, 5, 6, 7, 8, 9, 10);

void setup() 
{
    Serial.begin(9600);
    
  // Print a message to the LCD.
  lcd.begin(16, 2);
  lcd.print("Temperature");
  // lcd.setCursor(1, 1);        //2nd line
  // lcd.print("line 2");
}

void loop() 
{
 //getting the voltage reading from the temperature sensor
 int reading = analogRead(sensorPin);   
 
 // converting that reading to voltage, for 3.3v arduino use 3.3
 float voltage = reading * 5.0;
 voltage /= 1024.0; 
 
 // print out the voltage
 Serial.print(voltage); Serial.println(" volts");
 
 // now print out the temperature
 float temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset
                                               //to degrees ((voltage - 500mV) times 100)
                                               
 Serial.print(temperatureC); Serial.println(" degrees C");
 // now convert to Fahrenheit
 float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
 Serial.print(temperatureF); Serial.println(" degrees F");
  delay(5000);                                     //waiting a second
 
 
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(temperatureF); lcd.print(" deg. F");
}

I am attempting to add a pulse/BPM value to the display (which currently shows temp). I am attempting to modify the pulse code so that i can only show bpm on the 16x2. Below is the code that is giving me issues (and causing my micros to no longer work with my pc). [Please note: The pulse sensor code (which is giving me issues) is surrounded by stars “******”]

int sensorPin = A0;

//*****************************************************************************************************
// PULSE SENSOR CODE
int pulsePin = A1;                 // Pulse Sensor purple wire connected to analog pin A1
int blinkPin = 13;                // pin to blink led at each beat

// 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.
//*****************************************************************************************************

// included in the library code:
#include <Adafruit_CharacterOLED.h>
Adafruit_CharacterOLED lcd(OLED_V2, 4, 5, 6, 7, 8, 9, 10);

void setup() {
  
  //*****************************************************************************************************
//PULSE CODE (to make pin led blink to heartbeat )
    pinMode(blinkPin,OUTPUT);         // pin that will blink to your heartbeat!
    Serial.begin(115200);
     interruptSetup();  
     //*****************************************************************************************************
     
  // Print a message to the LCD.
  lcd.begin(16, 2);
  lcd.print("Jose Mendes");
  // lcd.setCursor(1, 1);        //2nd line
  // lcd.print("line 2");
}

void loop() 
{
 //getting the voltage reading from the temperature sensor
 int reading = analogRead(sensorPin);   
 
 // converting that reading to voltage, for 3.3v arduino use 3.3
 float voltage = reading * 5.0;
 voltage /= 1024.0; 
 
 // print out the voltage
 Serial.print(voltage); Serial.println(" volts");
 
 // now print out the temperature
 float temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset
                                               //to degrees ((voltage - 500mV) times 100)
                                               
 Serial.print(temperatureC); Serial.println(" degrees C");
 // now convert to Fahrenheit
 float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
 Serial.print(temperatureF); Serial.println(" degrees F");
  delay(5000);                                     //waiting a second
 
 
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(temperatureF); lcd.print(" deg. F");
  
//***************************************************************************************************** 
// MORE PULSE CODE FOR BPM
  if (QS == true){ // Quantified Self flag is true when arduino finds a heartbeat
Serial.println(BPM); // only print BPM variable without the leading 'B'
QS = false; // reset the Quantified Self flag for next time 
}


delay(20); // take a break
//*****************************************************************************************************
}

Thanks for taking time to read my post! :slight_smile:

HERE IS THE CODE PROVIDED WITH THE PULSE SENSOR:
(I only need the BPM value and dont care for all the other stuff. I tried modifying it to put in my temp/display code but keep faling)

/*
>> 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.

*/


//  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, 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.


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
        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
  }

I also have the interrupt for the code if needed. I believe the interrupt is fine… My objective is to display the BPM on the 16x2. Thanks you all in advance!! :slight_smile:

Flashing a sketch with the Arduino IDE does not brick the Arduino. What do you mean "lost"? Are you sure you don't have a hardware/hookup problem?

I am a beginner to programming but i feel confident in all my connections (i have some wiring experience from when i working HVAC). i wired temp sensor>>>pinA0 and purple wire from pulse sensor>>>pinA1.

i guess i could have a defective pulse sensor (but i doubt it bc light turns on and everything seems fine).

when i say " i lost 2 boards" i mean they stopped communicating with the computer. the computer says the device is not working properly (after connecting usb or resetting). the green lights on the boards contiune to pulsate when i press reset or connect the cable (and the blue lights work too).. i just cant seem to get it to work properly (it wont show under com anymore). i have tried resetting the board while uploading a new code and nothing.

I just cleaned up the code a bit making it a little bit easier to understand. The pulse sensor code (which is giving me issues) is surrounded by stars “******”. The problem started ONLY after I added this new part of the code to my LCD/temp sensor code.

int sensorPin = A0;

//*****************************************************************************************************
// PULSE SENSOR CODE
int pulsePin = A1;                 // Pulse Sensor purple wire connected to analog pin A1
int blinkPin = 13;                // pin to blink led at each beat

// 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.
//*****************************************************************************************************

// included in the library code:
#include <Adafruit_CharacterOLED.h>
Adafruit_CharacterOLED lcd(OLED_V2, 4, 5, 6, 7, 8, 9, 10);

void setup() {
  
  //*****************************************************************************************************
//PULSE CODE (to make pin led blink to heartbeat )
    pinMode(blinkPin,OUTPUT);         // pin that will blink to your heartbeat!
    Serial.begin(115200);
     interruptSetup();  
     //*****************************************************************************************************
     
  // Print a message to the LCD.
  lcd.begin(16, 2);
  lcd.print("Jose Mendes");
  // lcd.setCursor(1, 1);        //2nd line
  // lcd.print("line 2");
}

void loop() 
{
 //getting the voltage reading from the temperature sensor
 int reading = analogRead(sensorPin);   
 
 // converting that reading to voltage, for 3.3v arduino use 3.3
 float voltage = reading * 5.0;
 voltage /= 1024.0; 
 
 // print out the voltage
 Serial.print(voltage); Serial.println(" volts");
 
 // now print out the temperature
 float temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset
                                               //to degrees ((voltage - 500mV) times 100)
                                               
 Serial.print(temperatureC); Serial.println(" degrees C");
 // now convert to Fahrenheit
 float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
 Serial.print(temperatureF); Serial.println(" degrees F");
  delay(5000);                                     //waiting a second
 
 
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(temperatureF); lcd.print(" deg. F");
  
//***************************************************************************************************** 
// MORE PULSE CODE FOR BPM
  if (QS == true){ // Quantified Self flag is true when arduino finds a heartbeat
Serial.println(BPM); // only print BPM variable without the leading 'B'
QS = false; // reset the Quantified Self flag for next time 
}


delay(20); // take a break
//*****************************************************************************************************
}
     interruptSetup();

Where is this defined/declared?

PaulS:

     interruptSetup();

Where is this defined/declared?

I have it declared in a tab in that same sketch. I provided it below

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


void interruptSetup(){     
  // Initializes Timer2 to throw an interrupt every 2mS.
  TCCR0A = 0x02;
  TCCR0B = 0x04; 
  OCR0A = 0x7C; 
  TIMSK0 = 0x02; 
  sei();     
} 


// 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(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;                      
        }
      }

      if(firstBeat){                         // if it's the first time we found a beat, if firstBeat == TRUE
        firstBeat = false;                   // clear firstBeat flag
        secondBeat = true;                   // set the second beat flag
        sei();                               // enable interrupts again
        return;                              // IBI value is unreliable so discard it
      }   


      // 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 = false;                    // when we get the heartbeat back
  }

  sei();                                   // enable interrupts when youre done!
}// end isr

i havent touched the interrupt code. im scared of modifying anything in there

Ok I just bought a new board at Radio Shack. If possible, could someone please help me modify my error free code (the working display/temp sensor code at top of page)??

I am attempting to add a BPM value to the 16x2 display. It currently shows the temperature on display without any issues. As soon as i try to add the pulse code (surrounded by stars ***) it goes crazy. Display goes crazy and board stops communicating with PC.

Thanks again for reading my post!

I am having the same issue. I tried using the given code and then I can no longer load any program onto my micro, and the comm port will start dropping out and is no longer recognized. I found that if you reload a sample code( I used "blink") that it seems to fix the controller. It takes a few tries though. You have to press the hard reset button on the micro while the code is compiling, but before it uploads and hope for the best. The link below is what helped me with this.

http://forum.arduino.cc/index.php?topic=153674.0

First, can you upload any other simple sketch to the Micro?

Second, you don't seem to have posted the code for the entire sketch that is causing problems. You must show us that if you are to get any useful help. If it is long (hopefully not) please add it as an attachment so it is easier to download.

My guess is that your enormously long interrupt routine is the problem. I always try to restrict my interrupt code to 3 or 4 lines.

...R

My guess is that your enormously long interrupt routine is the problem.

Agreed. That, and the fact that you re-enable interrupts in the middle of your ISR.

Some of the comments in there are plain stupid. Some of the data types are, too.

      // keep a running total of the last 10 IBI values
      word runningTotal = 0;                  // clear the runningTotal variable

Do you KNOW what size a word is? If not, don't use it. This isn't Microsoft, and you won't be fired for not using a stupid type they invented. You are not clearing the variable. You are assigning it an initial value.

I changed the IRQ routine to use timer1 instead of timer2 and it works, no com port issues. Use:

TCCR1A = 0x02; TCCR1B = 0x04; OCR1A = 0x7C; TIMSK1 = 0x02;

and then change 'timer2' to 'timer1' in the ISR method.