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Arduino: Find the greatest value

e14 Contributor

Dear element14 members,

 

     I am doing a science fair project where I am taking 10 readings from a photo-resistor and trying to take the greatest value to do something else. Is there a simpler code than making a lot of  if statements? .....or maybe an IC or something?

 

Thanks In Advance,

 

Blockman301

  • There are 2 straight forward ways to approach this

     

    1) If you are reading the numbers one at a time, simply compare the current number to the last number, if it is greater, keep it, else throw it away

     

    2) if you collect all the numbers in an array, loop over the array and store the current value in a temp variable, then proceed as above.

     

    Either of these methods should be fine for 10 values.

     

    Mike

  • in reply to mconners

    Dear Mike,

     

    I'm sorry but I'm sorta new to arduino. Could you maybe show me an example code or lead me to one. That would be super helpful.

     

    Thanks in advance,

    Blockman301

  • I'm going to skip all the arduino setup, you've got to do some work image

    readFromPR() would be your method to read from the photo resistor, the following is method 1 I described.

     

    int maxVal = 0;

    int val,ii;

     

    loop(){

         for(ii=0;ii<10;ii++){

              val = readFromPR();

              if(val > maxval)

                   maxval = val;

         }

         printf("maxval = %d", maxVal);

    // Additional processing

    }

     

     

    Alternatively, method 2

     

    int maxVal = 0;

    int val[10];

    int ii;

     

    loop(){

         for(ii=0; ii< 10;ii++)

              val[ii] = readFromPR();

     

      for(ii=0;ii<10,ii++){

         if(val[ii] > maxVal)

              maxVal = val[ii]

    }

    printf("maxval = %d", maxVal);

    // Additional processing

    }



    something along those lines,


    Good luck,


    Mike