array average

Using Arduino Programming Questions
1

Hi guys I need some help, I am fairly new to arduino, I have an array of 100 integers and I need the average of these integers, how can I do it?

This is my code;

for (int x = 0; thisPin < 100; x++)
{
adcValue1[x] = analogRead(phototransistorPin1);
adcValue2[x] = analogRead(phototransistorPin2);
adcValue3[x] = analogRead(phototransistorPin3);
adcValue4[x] = analogRead(phototransistorPin4);
}

now I need the average of each adcValue
Thanks

2

What Arduino, or compatible, device is this running?

3

I am using arduino mega 2560

4

Hard to say with bullet point style code

5

I'm sorry that was just a typing error,

This is the code: for (int x = 0; x< 100; x++)
{
adcValue1= analogRead(phototransistorPin1);
adcValue2= analogRead(phototransistorPin2);
adcValue3= analogRead(phototransistorPin3);
adcValue4= analogRead(phototransistorPin4);
}

6

float runningTotal = 0;
float average = 0;
for (int x = 0; x< 100; x++)
{

adcValue1= analogRead(phototransistorPin1);
runningTotal = adcValue1 + runningTotal;
adcValue2= analogRead(phototransistorPin2);
runningTotal = adcValue1 + runningTotal;
adcValue3= analogRead(phototransistorPin3);
runningTotal = adcValue1 + runningTotal;
adcValue4= analogRead(phototransistorPin4);

average = runningTotal/x;

}

7 
for (int x = 0; thisPin < 100; x++) 
{ 
    adcValue1[x] = analogRead(phototransistorPin1);
    adcValue2[x] = analogRead(phototransistorPin2);
    adcValue3[x] = analogRead(phototransistorPin3);
    adcValue4[x] = analogRead(phototransistorPin4);
}

You need to use [ code ] [ /code ] tags to stop the forum software from mangling your code.

To generate an average, add up all the samples and divide by the number of samples.

long total = 0;
for(int x = 0; x < 100; x++)
{
    total += analogRead(phototransistorPin1);
}
adcValue1 = total/100;

Since you're doing the same thing four times, it would make sense to use arrays to hold your pins and to hold the resulting averages.

const int NUM_PINS = 4;
const int phototransistorPin[NUM_PINS] = { 2, 3, 4, 5 }; // substitute whatever pins you're using

...


long average[NUM_PINS];
long total[NUM_PINS];
for(int pin = 0; pin < NUM_PINS; pin++)
{
  total[pin] = 0;
  for(int sample = 0; sample < 100; sample++)
  {
    total[pin] += analogRead(phototransistorPin[pin]);
  }
  average[pin] = total[pin]/100;
}
8

Thank you all!