Interrupt Stopped working

Projects Programming
1

Hi guys so my code had been running successfully yesterday and now today the interrupt function is not working... Can any one see a problem?

Thanks!

#include <PID_v1.h>
#include <PWM.h>
#include <SPI.h>
#include <LiquidCrystal.h>

int32_t frequency = 167; //frequency (in Hz)

const int numReadings= 3;

//exhaust pressure sensor
int ebp_readings[numReadings];      
int ebp_index = 0;                  
float ebp_total = 0;                  
float ebp_average = 0; 
const int ebp = A0;

//throttle position sensor
int tps_readings[numReadings];      
int tps_index = 0;                  
float tps_total = 0;                  
float tps_average = 0; 
const int tps = A1;
unsigned long tps_counter = 0;

//vehicle speed sensor
unsigned long current_time2;
unsigned long previous_time2 = 0;
volatile int vss_counter = 0;
unsigned long vss_freq = 0;
const int vssIn = 2;

//Relay
const int relay = 12;

//PWM out pin
const int pwmOut = 9;

//PID output
float brake_output;

// LCD timer
unsigned long current_time1;
unsigned long previous_time1 = 0;


//pid information
double Setpoint, Input, pidOutput;
PID myPID(&Input, &pidOutput, &Setpoint,1,0,0, DIRECT);

// initialize lcd
LiquidCrystal lcd (8, 7, 6, 5, 4, 3);
const int test = 11;

void setup() {
  pinMode(tps, INPUT);
  pinMode(ebp, INPUT);
  pinMode(relay, OUTPUT);
  pinMode(pwmOut, OUTPUT);
  pinMode(vssIn, INPUT);
  digitalWrite(vssIn, HIGH);
  
  pinMode(test, OUTPUT);
  pwmWrite(test, 200);
   
  //vehicle speed sensor
  attachInterrupt(0, vspeed, FALLING);
  
  //exhaust pressure sensor
  for (int ebp_thisReading = 0; ebp_thisReading < numReadings; ebp_thisReading++)
    ebp_readings[ebp_thisReading] = 0;

    //throttle position sensor
  for (int tps_thisReading = 0; tps_thisReading < numReadings; tps_thisReading++)
    tps_readings[tps_thisReading] = 0;    
    
   //initialize all timers except for 0, to save time keeping functions
  InitTimersSafe(); 
  //sets the frequency for pwmOut pin 9
  bool success = SetPinFrequencySafe(pwmOut, frequency);  //change to pwmOut after testing
  //if the pin frequency was set successfully, turn pin 13 on
  if(success) {
    pinMode(pwmOut, OUTPUT);
  }

  //initialize PID variables
  Input = ebp_average;
  Setpoint = 356;  //test value = 20 psig
  myPID.SetOutputLimits(38, 115);

  //turn the PID on
  myPID.SetMode(AUTOMATIC);    
  
  // lcd setup
  lcd.begin(16, 2);
  lcd.clear();
  lcd.print("BRAKE%:");
  lcd.setCursor(0,1);
  lcd.print("EBP:");

}

void vspeed(){
  ++vss_counter;
}

void loop() {
  
   current_time1 = millis();
  // LCD Display
  if(current_time1 - previous_time1 > 400){
    previous_time1 = current_time1;
    
  //print brake output
  lcd.setCursor(7, 0);
  lcd.print("   ");
  lcd.setCursor(7,0);
  lcd.print(brake_output, 0);
   
  //print exhaust pressure sensor measurement
  lcd.setCursor(4, 1);
  lcd.print("   ");
  lcd.setCursor(4, 1);
  lcd.print(((ebp_average * 0.00488 * 19) - 12), 0);
  
  lcd.setCursor(12,0);
  lcd.print("    ");
  lcd.setCursor(12,0);
  lcd.print(vss_freq);
  
  lcd.setCursor(12,1);
  lcd.print("    ");
  lcd.setCursor(12,1);
  lcd.print (tps_counter);
 
  }

  //exhaust pressure sensor
  ebp_total= ebp_total - ebp_readings[ebp_index];         
  ebp_readings[ebp_index] = analogRead(ebp); 
  ebp_total= ebp_total + ebp_readings[ebp_index];         
  ebp_index = ebp_index + 1;                    
  if (ebp_index >= numReadings)              
    ebp_index = 0;                           
    
  ebp_average = ebp_total / numReadings;    
  
  //throttle position sensor
  tps_total= tps_total - tps_readings[tps_index];         
  tps_readings[tps_index] = analogRead(tps); 
  tps_total= tps_total + tps_readings[tps_index];         
  tps_index = tps_index + 1;                    
  if (tps_index >= numReadings)              
    tps_index = 0;                           
    
  tps_average = tps_total / numReadings; 
  

  //tps counter
  if(tps_average <=85){
    ++tps_counter;
  }
  else{
    tps_counter = 0;
  }
  
  //vehicle speed sensor
  current_time2 = millis();
    
    if(current_time2 - previous_time2 >= 1000) {
    vss_freq = vss_counter;
    vss_counter = 0;
    previous_time2 = current_time2;
    }
    
  //Output
  if(tps_counter >= 3000 && vss_counter >= 44){
    digitalWrite(relay, HIGH);
    Input = ebp_average;
    myPID.Compute();
    pwmWrite(pwmOut, pidOutput); 
    brake_output = (((pidOutput / 255) * 100) * 2);
   }
    else{
    digitalWrite(relay, LOW);
    pwmWrite(pwmOut, 0);
    brake_output = 0;
  }
   
}
2

If the code has not changed then you have changed the circuit somehow.

3

I disconnected everything from the arduino and am simulating a pulse using an analog write on pin 11 which goes to an led which does light up. I have a wire going from the positive side of the led to pin 2 (interrupt 0) and it is still not counting pulses, all I am getting is zero.

Thanks

4

Even this doesn't work. I am at a loss.

const int test = 11;

int vss = 2;

//vehicle speed sensor
unsigned long current_time2;
unsigned long previous_time2 = 0;
volatile long vss_counter = 0;
unsigned long vss_freq = 0;

unsigned long current_time1;
unsigned long previous_time1 = 0;

void setup(){
  pinMode(vss, INPUT);
  digitalWrite(vss, HIGH);
  pinMode(test, OUTPUT);
  analogWrite(test, 200);
  
  attachInterrupt(vss, vspeed, FALLING);
  
  Serial.begin(9600);
  
}

void vspeed(){
  vss_counter++;
}

void loop(){

    
    Serial.println(vss_counter);

  delay(1000);

    
}
5

Forget about writing to a pin to simulate a pulse. Simply take a wire from the pin and short it to GND manually to create the interrupt. On a Uno the metal case of the USB socket is a handy large ground point.

6

I tried manually grounding the wire to the usb socket and it still does not register an interrupt.

I appreciate the help UKHeliBob anything else I should try?

7

mitchedwards:
Even this doesn't work.

Do you mean it just writes out 0 lots of times?

I suggest you review the documentation for attachInterrupt(), especially the difference between pin numbers and interrupt numbers and the relationship between them. Unless you're running on a Due, you're using the wrong interrupt number.