an error I didn't unsredstand

what's this error meaning to? how can i fix that?

Interrupt:27: error: expected constructor, destructor, or type conversion before '(' token

thanks.

Do you mind posting you're code so we can see where the problem might be? It normally occurs when you miss a bracket somewhere..

That you're missing something (colon, semicolon, curly, ...) somewhere. Post the code and the full error message. Use codetags for each

[code]your code or error message here [/code]

I have 2 files.
this is the first:

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

void interruptSetup(){
// Initializes Timer2 to throw an interrupt every 2mS.
TCCR2A = 0x02; // DISABLE PWM ON DIGITAL PINS 3 AND 11, AND GO INTO CTC MODE
TCCR2B = 0x06; // DON’T FORCE COMPARE, 256 PRESCALER
OCR2A = 0X7C; // SET THE TOP OF THE COUNT TO 124 FOR 500Hz SAMPLE RATE
TIMSK2 = 0x02; // ENABLE INTERRUPT ON MATCH BETWEEN TIMER2 AND OCR2A
sei(); // MAKE SURE GLOBAL INTERRUPTS ARE ENABLED
}

// 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 *= 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 = rate[i+1]; // and drop the oldest IBI value_
    _ runningTotal += rate*; // 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
this is the second:
// 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*
* 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*
* }*

Please use the code tags... Also, your first file there seems to have lots of undefined variables such as pulsePin and Signal. You can use the error messages to verify this first. It will also tell you which line is missing the parenthesis.

this:
ISR(TIMER2_COMPA_vect){

probably needs a type specifier on it. Try

void ISR(TIMER2_COMPA_vect){