Need help understanding analogread into arrays

[gunikia91]

Hi guys! I'm relatively new to the arduino platform and recently I've been trying to store the analogRead values into an array, and based on the array I aim to perform some calculations.

However I realised the values that I'm receiving from the analogRead and the values that I get from the array is different. Is it possible that I've missed out something crucial? I believe that my code to store the analog values into the array should be correct, but since I'm unable to see the same values when I access the array could this be caused by any hardware limitations of the Arduino?

I've attached my codes below and I apologize in advance if this seems to be a noob-ish question

Thanks!

const int numReadings = 500;
int threshold = 500;
int readings[numReadings];      // the readings from the analog input
int readIndex = 0;              // the index of the current reading
int inputPin = A0;


void setup() {
  Serial.begin(9600);        // initialize serial communication with computer:
  for (int thisReading = 0; thisReading < numReadings; thisReading++) 
  {
    readings[thisReading] = 0;    //   initialize all the readings to 0:
  }
}

void loop() {
  
  readings[readIndex] = analogRead(inputPin);   // read from the sensor

  Serial.println(readings[readIndex]);

 
  readIndex = readIndex + 1;       // advance to the next position in the array

  if (readIndex >= numReadings) // if we're at the end of the array...
  {
    for(int i=0;i<readIndex;i=i+1)
    {
      Serial.println(readings[i]);
    }
    readIndex = 0;     // ...wrap around to the beginning:
    delay(2000);
  }
 
}

[sterretje]

The code that your presented works; for testing, I did limit the number of readings to 10 and increased the delay to 10 seconds so one has the time to compare the numbers

However, 500 integers is 1 kB of SRAM space. If other code requires lots of (or big) variables, you might run into problems (at least on a 328 based board).

[qingshan]

Yes. I have the same question as to the poster. Do you have any ideas that can make it work for an array whose length is 500?

[sterretje]

I suggest you post your code.