Arduino stuck when I disable Timer 2 Interrupt

Question

#define TIM2_EN() (TIMSK2 = 0x02)
#define TIM2_DIS() (TIMSK2 = 0x00)
//HEART SENSOR
// Include Libraries
#include "Arduino.h"
class PulseSensor
{
public:
 static void begin(int pulsePin);
 static volatile int BPM; // used to hold the pulse rate
 static volatile int Signal; // holds the incoming raw data
 static volatile int IBI; // holds the time between beats, must be seeded!
 static volatile boolean QS; // becomes true when Arduoino finds a beat.
};
// Pin Definitions
#define HEARTPULSE_PIN_SIG A0
// Global variables and defines
// object initialization
PulseSensor heartpulse;
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
volatile boolean Pulse = false; // true when pulse wave is high, false when it's low
volatile int pulsePin;
volatile int PulseSensor::IBI = 600; // holds the time between beats, must be seeded!
volatile int PulseSensor::BPM; // used to hold the pulse rate
volatile int PulseSensor::Signal; // holds the incoming raw data
volatile boolean PulseSensor::QS = false; // becomes true when Arduino finds a beat
void PulseSensor::begin(int pPin)
{
 pinMode(pulsePin, INPUT);
 pulsePin = pPin;
 // Initializes Timer1 to throw an interrupt every 2ms.
 TCCR1A = 0x00;
 TCCR1B = 0x0C; // CTC (Compare match mode) and ClockIO/256
 OCR1A = 0x7C; // 2 ms
 TIMSK1 = 0x02;
 sei(); // MAKE SURE GLOBAL INTERRUPTS ARE ENABLED
}
// THIS IS THE TIMER 1 INTERRUPT SERVICE ROUTINE. 
// Timer 1 makes sure that we take a reading every 2 miliseconds
ISR(TIMER1_COMPA_vect)
{ // triggered when Timer1 counts to 124
 cli(); // disable interrupts while we do this
 PulseSensor::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(PulseSensor::Signal < thresh && N > (PulseSensor::IBI/5)*3){ // avoid dichrotic noise by waiting 3/5 of last IBI
 if (PulseSensor::Signal < T){ // T is the trough
 T = PulseSensor::Signal; // keep track of lowest point in pulse wave 
 }
 }
 if(PulseSensor::Signal > thresh && PulseSensor::Signal > P){ // thresh condition helps avoid noise
 P = PulseSensor::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 ( (PulseSensor::Signal > thresh) && (Pulse == false) && (N > (PulseSensor::IBI/5)*3) )
 { 
 Pulse = true; // set the Pulse flag when we think there is a pulse
 PulseSensor::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] = PulseSensor::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] = PulseSensor::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 
 PulseSensor::BPM = 60000/runningTotal; // how many beats can fit into a minute? that's BPM!
 PulseSensor::QS = true; // set Quantified Self flag 
 // QS FLAG IS NOT CLEARED INSIDE THIS ISR
 } 
 }
 if (PulseSensor::Signal < thresh && Pulse == true){ // when the values are going down, the beat is over
 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
//LDR SENSOR
int sensorPin = A1; // select the input pin for LDR
int sensorValue = 0; // variable to store the value coming from the sensor
//LCD
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4); // set the LCD address to 0x27 for a 16 chars and 2 line display
//DHT
#include "dht.h"
int dht_apin = 2; 
dht DHT;
//HEART RATE SENSOR
unsigned long current_time,start_time=0;
int BPM,Interval;
void setup(){
 Serial.begin(115200);
 heartpulse.begin(HEARTPULSE_PIN_SIG);
 delay(1500);
 lcd.init(); // initialize the lcd 
 lcd.backlight();
 lcd.print(" INITIALISING");
 delay(2500);
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print(" CHECKING HEART");
 lcd.setCursor(0,1);
 lcd.print(" RATE NOW......");
 delay(2000);
 lcd.clear();
}
void loop() {
 current_time = millis();
 if ( current_time-start_time < 30000 ) {
 BPM = heartpulse.BPM;
 Interval = heartpulse.IBI; 
 lcd.print(" SYNCHRONIZING ");
 lcd.setCursor(0,1);
 lcd.print(" BEATS:"); 
 lcd.print(BPM);
 lcd.clear();
 } else {
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("BEATS PER MINUTE");
 lcd.setCursor(6,1);
 lcd.print(BPM); 
 Serial.print(BPM);
 Serial.println('b');
 delay(4000);
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print(" BEAT INTERVAL ");
 lcd.setCursor(7,1);
 lcd.print(Interval); 
 Serial.print(Interval);
 Serial.println('p');
 delay(4000);
 TIM2_DIS(); //Enable TIMER2 Interrupt
 DHT.read11(dht_apin); 
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print(" HUMIDITY ");
 lcd.setCursor(6,1);
 lcd.print(DHT.humidity);
 lcd.print("%");
 Serial.print(DHT.humidity);
 Serial.println('h');
 delay(4000);
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print(" TEMPERATURE ");
 lcd.setCursor(5,1);
 lcd.print(DHT.temperature);
 lcd.print("C");
 Serial.print(DHT.temperature);
 Serial.println('t');
 TIM2_EN(); //Disable TIMER2 Interrupt
 delay(4000); 
 sensorValue = analogRead(sensorPin); // read the value from the sensor
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("LIGHT INTENSITY");
 lcd.setCursor(7,1);
 lcd.print(sensorValue);
 Serial.print(sensorValue);
 Serial.println('l');
 delay(4000);
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print(" CHECKING HEART");
 lcd.setCursor(0,1);
 lcd.print(" RATE NOW......");
 delay(2000); 
 lcd.clear();
 start_time = millis();
 }
}

I am trying to run LDR,PULSE AND DHT11 sensor together. DHT11 was not giving out readings along with pulse sensor before so I searched stack exchange and found out this solution.

DHT11 and Pulse sensor incompatibility?

But now the problem is Arduino gets stuck at the line when I disable timer 2 interupt -

TIM2_EN(); //Disable TIMER2 Interrupt

Any solution?

• jsotola: are you sure that TIM2_EN() disables the interrupt? ...... what does TIM2_DIS() do?
• Rohan: I came up with this idea from here. arduino.stackexchange.com/questions/21489/… The code given in this works with this solution but my code is stuck and it is not even reading values from DHT
• Rohan: If i remove this line the code isn't stuck anymore- TIM2_EN(); //Disable TIMER2 Interrupt....But still Arduino is not able to read values from DHT11.
• Rohan: I do not know, can you explain in detail.
• Rohan: From Github I got this - TIMSK2 = 0x02; // ENABLE INTERRUPT ON MATCH BETWEEN TIMER2 AND OCR2A. What can I do to read values from DHT11 and pulse sensor in the same program?