Arduino/build/shared/examples/03.Analog/Smoothing/Smoothing.ino

/*

  Smoothing

  Reads repeatedly from an analog input, calculating a running average
  and printing it to the computer.  Keeps ten readings in an array and
  continually averages them.

  The circuit:
    * Analog sensor (potentiometer will do) attached to analog input 0

  Created 22 April 2007
  By David A. Mellis  <dam@mellis.org>
  modified 9 Apr 2012
  by Tom Igoe
  http://www.arduino.cc/en/Tutorial/Smoothing

  This example code is in the public domain.


*/


// Define the number of samples to keep track of.  The higher the number,
// the more the readings will be smoothed, but the slower the output will
// respond to the input.  Using a constant rather than a normal variable lets
// use this value to determine the size of the readings array.
const int numReadings = 10;

int readings[numReadings];      // the readings from the analog input
int index = 0;                  // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average

int inputPin = A0;

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

void loop() {
  // subtract the last reading:
  total = total - readings[index];
  // read from the sensor:
  readings[index] = analogRead(inputPin);
  // add the reading to the total:
  total = total + readings[index];
  // advance to the next position in the array:
  index = index + 1;

  // if we're at the end of the array...
  if (index >= numReadings)
    // ...wrap around to the beginning:
    index = 0;

  // calculate the average:
  average = total / numReadings;
  // send it to the computer as ASCII digits
  Serial.println(average);
  delay(1);        // delay in between reads for stability
}