Is it possible to have 5 interrupts on Uno?

FrozenLiquor · March 19, 2019, 11:02pm

I am doing a project which requires me to use 5 press sensors to control 5 LEDs independently/separately, which means that when I press button 1, 2 and 3 at the same time, the LED 1, 2 and 3 will be on simultaneously and so on. So, to do that, I need to use 5 interrupts.

I am using Arduino Uno. My plan is that I will use PIN 2 and PIN 3 for two sensors (hardware interrupt), and use Timer1 for another sensor (software interrupt). By now I still have two interrupt to do, and I am trying to use PinChangeInterrupt for them.

However, I found that this does not work. All other interrupts are working, but not the PinChangeInterrupt. And I found that when I use PIN2 and PIN3 as my hardware interrupts, the PinChangeInterrupt will not work at all, but if I just leave PIN2 and PIN3 empty, the PinChangeInterrupt works, but the LED is very dim.

Could someone please help me? Or just tell me if it is really possible having 5 interrupts on Uno?

My code is here. I am now trying to play with 4 sensors.

#include "PinChangeInterrupt.h"
#include "TimerOne.h"
#define interrupt0 0
#define interrupt1 1

#define sensor1 11 //controlled by timer1
#define sensor2 2 //interrupt 0
#define sensor3 3 //interrupt 1
#define sensor4 4 //pinchangeinterrupt

#define LED1 5
#define LED2 6
#define LED3 7
#define LED4 8

volatile byte flag0, flag1, flag2, flag3;

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);

  pinMode(sensor1, INPUT);
  pinMode(sensor2, INPUT);
  pinMode(sensor3, INPUT);
  pinMode(sensor4, INPUT);
  
  Serial.begin(9600);
  attachInterrupt(interrupt0,LED1ON,CHANGE);
  attachInterrupt(interrupt1,LED2ON,CHANGE);
  
  attachPinChangeInterrupt(sensor4,LED4ON,CHANGE);
  
  Timer1.initialize(100000);
  Timer1.pwm(sensor1, 512); 
  Timer1.attachInterrupt(LED3ON);

}

void loop() {
  if(flag0 == 1){
    Serial.println("11111111");
    Serial.print(sensor1);
    flag0 = 0;
  }
  if(flag1 == 1){
    Serial.println("22222222");
    Serial.print(sensor2);
    flag1 = 0;
  }
    if(flag2 == 1){
    Serial.println("33333333");
    Serial.print(sensor3);
    flag2 = 0;
  }
    if(flag3 == 1){
    Serial.println("44444444");
    Serial.print(sensor4);
    flag3 = 0;
  }  
}

void LED1ON(){
  if (digitalRead(sensor2) == LOW){
    digitalWrite(LED1, LOW);
  }
  if (digitalRead(sensor2) == HIGH){
    digitalWrite(LED1, HIGH);
    //digitalWrite(LED1, LOW);
    flag0 = 1;
  }
}
void LED2ON(){
  if (digitalRead(sensor3) == LOW){
    digitalWrite(LED2, LOW);
  }
  if (digitalRead(sensor3) == HIGH){
    digitalWrite(LED2, HIGH);
    //JdigitalWrite(LED2, LOW);
    flag1 = 1;
  }
}
void LED3ON(){
  if (digitalRead(sensor1) == LOW){
    digitalWrite(LED3, LOW);
  }
  if (digitalRead(sensor1) == HIGH){
    digitalWrite(LED3, HIGH);
    //JdigitalWrite(LED2, LOW);
    flag2 = 1;
  }
}
void LED4ON(){
  if (digitalRead(sensor4) == LOW){
    digitalWrite(LED4, LOW);
  }
  if (digitalRead(sensor4) == HIGH){
    digitalWrite(LED4, HIGH);
    //JdigitalWrite(LED2, LOW);
    flag3 = 1;
  }
}

LarryD · March 19, 2019, 11:09pm

Why isn’t it good enough to just scan the switches every 10ms and look for change in state?

Interrupts are best for fast (not switches) devices.

FrozenLiquor · March 19, 2019, 11:17pm

I actually thought about it, but the way I did it did not allow me to control the switches independently, which means that even I press multiple sensors at the same time, only one LED will be on. Probably I did not do it correctly.

Could you please give me a little bit more information about how to do it?

LarryD · March 19, 2019, 11:23pm

Would the LEDs going on a few 100 microseconds apart from one another be a problem?

Your eyes will definitely not see any lag between the LEDs coming on.

LarryD · March 20, 2019, 12:15am

This should give you something to build on:

#define LED1 8
#define LED2 9
#define LED3 10
#define LED4 11

#define sensor1 2
#define sensor2 3
#define sensor3 4
#define sensor4 5

byte lastSensor1State;
byte lastSensor2State;
byte lastSensor3State;
byte lastSensor4State;

//Timer variables used
unsigned long currentMillis;
unsigned long pin13Millis;
unsigned long SwitchMillis;

//if these are not changed in the sketch, they can be const
unsigned long debounceMillis = 10UL;  //10ms
unsigned long ledOnTime      = 500UL; //500ms seconds

//**********************************************************************
void setup()
{
  Serial.begin(9600);

  pinMode(LED1, OUTPUT);
  digitalWrite(LED1, LOW);  //LED off

  pinMode(LED2, OUTPUT);
  digitalWrite(LED2, LOW);  //LED off

  pinMode(LED3, OUTPUT);
  digitalWrite(LED3, LOW);  //LED off

  pinMode(LED4, OUTPUT);
  digitalWrite(LED4, LOW);  //LED off

  digitalWrite(13, LOW);
  pinMode(13, OUTPUT);

  pinMode(sensor1, INPUT_PULLUP);
  pinMode(sensor2, INPUT_PULLUP);
  pinMode(sensor3, INPUT_PULLUP);
  pinMode(sensor4, INPUT_PULLUP);

} //END of setup()

//**********************************************************************
void loop()
{
  //save the current time
  currentMillis = millis();

  //*************************************
  //Heartbeat LED
  //Toggle LED on and off, helps show if there is blocking code
  if (currentMillis - pin13Millis >= ledOnTime)
  {
    pin13Millis = millis();             //re-initialize Timer
    digitalWrite(13, !digitalRead(13)); //toggle LED condition
  }

  //*************************************
  //is it time to check the switches?
  if (currentMillis - SwitchMillis >= debounceMillis)
  {
    //code here runs every debounceMillis ms
    SwitchMillis = millis(); //re-initilize Timer
    
    //go check the switches
    checkSwitches();
  }

} //END of loop()


//**********************************************************************
//                  c h e c k S w i t c h e s ( )
//
void checkSwitches()
{
  //reusable for all the switches
  boolean thisState;

  //check if this switch has changed state
  thisState = digitalRead(sensor1);

  if (thisState != lastSensor1State)
  {
    //update the switch state
    lastSensor1State = thisState;

    //this switch position has changed so do some stuff
    //"LOW condition code"
    //has switch gone from HIGH to LOW?
    if (thisState == LOW)
    {
      //Do some LOW switch stuff here
      digitalWrite(LED1, HIGH); //turn on LED
    }
    else
    {
      //Do some HIGH switch stuff here
      digitalWrite(LED1, LOW); //turn off LED
    }

  } //END of sensor1 code

  //**************************************
  //check if this switch has changed state
  thisState = digitalRead(sensor2);

  if (thisState != lastSensor2State)
  {
    //update the switch state
    lastSensor2State = thisState;

    //this switch position has changed so do some stuff
    //"LOW condition code"
    //has switch gone from HIGH to LOW?
    if (thisState == LOW)
    {
      //Do some LOW switch stuff here
      digitalWrite(LED2, HIGH); //turn on LED
    }
    else
    {
      //Do some HIGH switch stuff here
      digitalWrite(LED2, LOW); //turn off LED
    }

  } //END of sensor2 code

  //**************************************
  //check if this switch has changed state
  thisState = digitalRead(sensor3);

  if (thisState != lastSensor3State)
  {
    //update the switch state
    lastSensor3State = thisState;

    //this switch position has changed so do some stuff
    //"LOW condition code"
    //has switch gone from HIGH to LOW?
    if (thisState == LOW)
    {
      //Do some LOW switch stuff here
      digitalWrite(LED3, HIGH); //turn on LED
    }
    else
    {
      //Do some HIGH switch stuff here
      digitalWrite(LED3, LOW); //turn off LED
    }

  } //END of sensor3 code

  //**************************************
  //check if this switch has changed state
  thisState = digitalRead(sensor4);

  if (thisState != lastSensor4State)
  {
    //update the switch state
    lastSensor4State = thisState;

    //this switch position has changed so do some stuff
    //"LOW condition code"
    //has switch gone from HIGH to LOW?
    if (thisState == LOW)
    {
      //Do some LOW switch stuff here
      digitalWrite(LED4, HIGH); //turn on LED
    }
    else
    {
      //Do some HIGH switch stuff here
      digitalWrite(LED4, LOW); //turn off LED
    }
    
  } //END of sensor4 code
  
} //END of checkSwitches()

//**********************************************************************

FrozenLiquor · March 20, 2019, 1:02am

Sry I was working on it and did not check the forum for a while.

Thank you very much for your help and I'll learn your code now.

And it is my bad that I did not mention that for this project, the LED needs to stay on when I press and hold the sensor.

FrozenLiquor · March 20, 2019, 1:20am

larryd:
This should give you something to build on:
#define LED1 8

#define LED2 9
#define LED3 10
#define LED4 11

#define sensor1 2
#define sensor2 3
#define sensor3 4
#define sensor4 5

byte lastSensor1State;
byte lastSensor2State;
byte lastSensor3State;
byte lastSensor4State;

//Timer variables used
unsigned long currentMillis;
unsigned long pin13Millis;
unsigned long SwitchMillis;

//if these are not changed in the sketch, they can be const
unsigned long debounceMillis = 10UL; //10ms
unsigned long ledOnTime = 500UL; //500ms seconds

//**********************************************************************
void setup()
{
Serial.begin(9600);

pinMode(LED1, OUTPUT);
digitalWrite(LED1, LOW); //LED off

pinMode(LED2, OUTPUT);
digitalWrite(LED2, LOW); //LED off

pinMode(LED3, OUTPUT);
digitalWrite(LED3, LOW); //LED off

pinMode(LED4, OUTPUT);
digitalWrite(LED4, LOW); //LED off

digitalWrite(13, LOW);
pinMode(13, OUTPUT);

pinMode(sensor1, INPUT_PULLUP);
pinMode(sensor2, INPUT_PULLUP);
pinMode(sensor3, INPUT_PULLUP);
pinMode(sensor4, INPUT_PULLUP);

} //END of setup()

//**********************************************************************
void loop()
{
//save the current time
currentMillis = millis();

//*************************************
//Heartbeat LED
//Toggle LED on and off, helps show if there is blocking code
if (currentMillis - pin13Millis >= ledOnTime)
{
pin13Millis = millis(); //re-initialize Timer
digitalWrite(13, !digitalRead(13)); //toggle LED condition
}

//*************************************
//is it time to check the switches?
if (currentMillis - SwitchMillis >= debounceMillis)
{
//code here runs every debounceMillis ms
SwitchMillis = millis(); //re-initilize Timer

//go check the switches
checkSwitches();
}

} //END of loop()

//**********************************************************************
// c h e c k S w i t c h e s ( )
//
void checkSwitches()
{
//reusable for all the switches
boolean thisState;

//check if this switch has changed state
thisState = digitalRead(sensor1);

if (thisState != lastSensor1State)
{
//update the switch state
lastSensor1State = thisState;

//this switch position has changed so do some stuff
//"LOW condition code"
//has switch gone from HIGH to LOW?
if (thisState == LOW)
{
//Do some LOW switch stuff here
digitalWrite(LED1, HIGH); //turn on LED
}
else
{
//Do some HIGH switch stuff here
digitalWrite(LED1, LOW); //turn off LED
}

} //END of sensor1 code

//**************************************
//check if this switch has changed state
thisState = digitalRead(sensor2);

if (thisState != lastSensor2State)
{
//update the switch state
lastSensor2State = thisState;

//this switch position has changed so do some stuff
//"LOW condition code"
//has switch gone from HIGH to LOW?
if (thisState == LOW)
{
//Do some LOW switch stuff here
digitalWrite(LED2, HIGH); //turn on LED
}
else
{
//Do some HIGH switch stuff here
digitalWrite(LED2, LOW); //turn off LED
}

} //END of sensor2 code

//**************************************
//check if this switch has changed state
thisState = digitalRead(sensor3);

if (thisState != lastSensor3State)
{
//update the switch state
lastSensor3State = thisState;

//this switch position has changed so do some stuff
//"LOW condition code"
//has switch gone from HIGH to LOW?
if (thisState == LOW)
{
//Do some LOW switch stuff here
digitalWrite(LED3, HIGH); //turn on LED
}
else
{
//Do some HIGH switch stuff here
digitalWrite(LED3, LOW); //turn off LED
}

} //END of sensor3 code

//**************************************
//check if this switch has changed state
thisState = digitalRead(sensor4);

if (thisState != lastSensor4State)
{
//update the switch state
lastSensor4State = thisState;

//this switch position has changed so do some stuff
//"LOW condition code"
//has switch gone from HIGH to LOW?
if (thisState == LOW)
{
//Do some LOW switch stuff here
digitalWrite(LED4, HIGH); //turn on LED
}
else
{
//Do some HIGH switch stuff here
digitalWrite(LED4, LOW); //turn off LED
}

} //END of sensor4 code

} //END of checkSwitches()

//**********************************************************************

Oh man, I am almost gonna cry now. This perfectly works for my project, except for the on/off of LEDs, cuz it's kind of flipped (on is off, off is on). Ill figure it out. Thank you very much!!!!!!!!!!!!!!

LarryD · March 20, 2019, 2:10am

Yes, depending on wiring things can be reversed.

FrozenLiquor · March 20, 2019, 3:17am

larryd:
Yes, depending on wiring things can be reversed.

2017-08-05_20-33-24.jpg1004×939 224 KB

You are a life savior for me. Thank you very much for your time and help!

Thank you very much!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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