I get an error when compling to arduino and am unsure why. any help is appreciated! SOLVED!

Using Arduino Programming Questions
1

im trying to make a sytsem to detect vibration from sensors and then light up an led and send a signal to max8 to play a sound and when i upload the code below to the arduino uno i get this errror:
Arduino: 1.8.19 (Windows Store 1.8.57.0) (Windows 10), Board: "Arduino Uno"

C:\Users\caley\Downloads\AAI_CW2_Project_Sketch\test_final\test_final.ino: In function 'void SetLedOn(int, int*)':

C:\Users\caley\Downloads\AAI_CW2_Project_Sketch\test_final\test_final.ino:59:45: warning: 'sizeof' on array function parameter 'leds' will return size of 'int*' [-Wsizeof-array-argument]

         for (int i = 1; i <= sizeof(leds); i++)

                                         ^

C:\Users\caley\Downloads\AAI_CW2_Project_Sketch\test_final\test_final.ino:57:43: note: declared here

     void SetLedOn(int ledId, int leds[])

                                       ^

C:\Users\caley\AppData\Local\Temp\cc1D5F4s.ltrans0.ltrans.o: In function `main':

C:\Users\caley\OneDrive\Documents\ArduinoData\packages\arduino\hardware\avr\1.8.5\cores\arduino/main.cpp:43: undefined reference to `setup'

collect2.exe: error: ld returned 1 exit status

exit status 1

Error compiling for board Arduino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

   //init variables
        int leds[] = { 2, 3, 4 };
        int numPads = 3;
        int threshold = 50;

        int state = 0;
        int baseTime = millis();
        int thisPress = 0;
        int lastPressed = 0;
        
        void loop()
        {
            //if in state>0 but more than 5secs elapsed since last press then reset to state0
            if( (state>0) && ( millis() > (baseTime+(5000*state))))
            {
                state = 0;
                SetLedOn(0,leds);
            }

            //test for padd press
            thisPress = GetPadPress(numPads, threshold);
            
            //if pad pressed detected and different from last pad pressed then move to next state and update leds/max
            if (thisPress != 0 && thisPress!=lastPressed)
            {
                state++;    //Increment state

                SetLedOn(thisPress,leds);  //turn the pads corresponding led on, turn off others

                Serial.println(state);  //set message to MAX
                                       
                                        //or alternatively to help in debugging 
                                        //String msgPrefix= "PadPress: ";
                                        //String msg = msgPrefix + state;
                                        //Serial.println(msg);
                                        //or alternatively you could send the pad that was pressed, or send both state and pad pressed
                
                //update the lastPressed
                lastPressed = thisPress;
            }
            
        }  //continue looping

        
        int GetPadPress(int numPads, int threshold)  //returns the number of the pad that was pressed, if press above threshold, otherwise returns 0
        {
            for (int i = 0; i < numPads; i++)  //poll each pad
            {
                if (analogRead(i) > threshold) { return i; }  //return on first detected pad press above threshold
            }
            return 0;
        }
        
        void SetLedOn(int ledId, int leds[])
        {  //Turn on specified LED, turn off all others, to turn off all leds pass ledId=0
            for (int i = 1; i <= sizeof(leds); i++)
            {
                if (i == ledId) { digitalWrite(leds[i], HIGH); }
                else { digitalWrite(leds[i], LOW); }
            }
        }
2

You must have a setup function, even if it does nothing.

3

what do you mean? im new to arduino so theres a lot im still learning

4

Look at any example Arduino program in the IDE. There will be at a minimum, two functions. Loop, which you have and setup, which you don't.

5

thanks that helped clear things up

6

Don't ignore this warning either.

(What made you think this was an installation issue?)

7

That's a pretty complex sketch for anyone just starting out.
If you started with a template of just

void setup()
{
}

void loop()
{
}

you'd have the basics.

8

I would code this as
#define NUMLEDS 3
int leds[NUMLEDS]={2,3,4};

and use:

for (int i = 1; i <= NUMLEDS; i++) in my code.
The sizeof(leds) is the size of an int pointer, 4 on most arduinos, but could be 8 on a 64-bit machine. sizeof(leds[0]) is the int size, which would be 2, or 4 on a 32-bit machine. It's pointer math, not the number of array elements.
My reasoning is that if you want to add, rearrange or delete leds in your project, you edit the #define and the array, and if they don't agree, the compiler will tell you you made a mistake. By basing your loop counter on the #define, if you change it, all the loops will automatically be in agreement.

9

I certainly would not use that in my code :wink:

10

That's what I get for copy paste, DOH!

for (int i = 1; i < NUMLEDS; i++)

11

Is better still.

12

You're good! :flushed:

13

@hap-ki-doh your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project.

14

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