(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/03.Analog/Smoothing/Smoothing.ino lang=arduino tabwidth=4:)

(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Smoothing/Smoothing.ino lang=arduino tabwidth=4:)

(:source http://github.com/arduino/Arduino/raw/new-extension/build/shared/examples/3.Analog/Smoothing/Smoothing.ino lang=arduino tabwidth=4:)

• for()

Smoothing

• For()

This sketch reads repeatedly from an analog input, calculating a running average and printing it to the computer. This example is useful for smoothing out the values from jumpy or erratic sensors, and also demonstrates the use of arrays to store data.

The code below sequentially stores 10 readings from your analog sensor into an arrays, one by one. With each new value, the sum of all the numbers is generated and divided, producing an average value which then be used to smooth outlying data. Because this averaging takes place each time a new value is added to the array (rather then waiting for 10 new values, for instance) there is no lag time in calculating this running average.

Altering the size of the array used, by changing numReadings to a larger value will smooth the data collected even further.

• AnalogInOutSerial - read an analog pin, map the result, and use that data to dim or brighten an LED

(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Smoothing/Smoothing.pde lang=arduino tabwidth=4:)

• serial()

Altering the size of the array used, by changing const int numReadings = 10, to a larger value will smooth the data collected even further.

(:divend:)

See Also:

• array
• if()
• [[Reference/serial]()

• AnalogInput - use a potentiometer to control the blinking of an LED
• AnalogInOutSerial - read an analog pin, map the result, and use that data to dim or brighten an LED
• Fade - use an analog input to fade an LED
• Smoothing - smooth multiple readings of an analog input
• Calibration - define a maximum and minimum for expected analog sensor values

The code below sequentially stores 10 readings from your analog sensor into an arrays, one by one. With each advancing value, the sum of all the numbers is generated and divided, producing an average value which then be used to smooth outlying data. Because this averaging takes place each time a new value is added to the array (rather then waiting for 10 new values, for instance) there is no lag time in calculating this running average.

The code below sequentially stores 10 readings from your analog sensor into an array, one by one. With each advancing value, the sum of all the numbers is generated and divided, producing an average value which then be used to smooth outlying data. Because this averaging takes place each time a new value is added to the array (rather then waiting for 10 new values, for instance) there is no lag time in calculating this running average.

The code below sequentially stores 10 readings from your analog sensor into an array, one by one. With each advancing value, the sum of all the numbers is generated and divided, producing an average value which then be used to smoothing outlying data. Because this averaging takes place each time a new value is added to the array (rather then waiting for 10 new values, for instance) there is no lag time in calculating this running average.

Changing the size of the array, from holding 10 values to, say, 20 will smooth your data even further.

Hardware

Reads repeatedly from an analog input, calculating a running average and printing it to the computer. This example is exceptionally useful for smoothing out the values from jumpy/erratic sensors, and also demonstrates the use of arrays to store data.

'Hardware

• Arduino Board
• Potentiometer

Connect one pin of a potentiometer to 5V, the center pin to analog pin 0, and the the last pin to ground.

 (:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Smoothing/Smoothing.pde lang=arduino  tabwidth=4:)

 (:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/Analog/Smoothing/Smoothing.pde lang=arduino  tabwidth=4:)

image developed using Fritzing. For more circuit examples, see the Fritzing project page

(:div class=code :)

 /*

   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>

   http://www.arduino.cc/en/Tutorial/Smoothing

 */

 // 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 = 0;

 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, DEC);               
 }

(:divend:)

click the image to enlarge

Schematic

click the image to enlarge

/*

  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>

  http://www.arduino.cc/en/Tutorial/Smoothing

• /

// respond to the input. Using a constant rather than a normal variable lets

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

  // 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, DEC);               

Reads repeatedly from an analog input, calculating a running average and printing it to the computer. Demonstrates the use of arrays.

Potentiometer on analog input pin 0.

  Serial.begin(9600);                     // initialize serial communication with computer

  Serial.println(average);                // send it to the computer (as ASCII digits)

Examples > Analog I/O

Smoothing

Reads repeatedly from an analog input, calculating a running average and outputting it to an analog output. Demonstrates the use of arrays.

Circuit

Potentiometer on analog input pin 0, LED on pin 9.

Code

/*

 * Smoothing
 * David A. Mellis <dam@mellis.org>
 *
 * Reads repeatedly from an analog input, calculating a running average
 * and outputting it to an analog output. 
 *
 * http://www.arduino.cc/en/Tutorial/Smoothing
 */

// 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 #define rather than a normal variable lets // use this value to determine the size of the readings array.

1. define 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 = 0; int outputPin = 9;

  for (int i = 0; i < NUMREADINGS; i++)
    readings[i] = 0;                      // initialize all the readings to 0

  total -= readings[index];               // subtract the last reading
  readings[index] = analogRead(inputPin); // read from the sensor
  total += readings[index];               // add the reading to the total
  index = (index + 1);                    // advance to the next index

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

  average = total / NUMREADINGS;          // calculate the average
  analogWrite(outputPin, average / 4);    // analog inputs go up to 1023, outputs to 255

[@

@]

1. define NUMSAMPLES 10

int samples[NUMSAMPLES]; int index = 0; int total = 0;

int sensor = 0; int actuator = 9;

void setup() {

  for (int i = 0; i < NUMSAMPLES; i++)
    samples[i] = 0;

}

void loop() {

  total -= samples[index];
  samples[index] = analogRead(sensor);
  total += samples[index];
  index = (index + 1) % NUMSAMPLES;
  analogWrite(actuator, total / NUMSAMPLES);

}