## Tutorial.Smoothing History

May 02, 2012, at 03:41 AM by Scott Fitzgerald -
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November 16, 2011, at 04:12 AM by Scott Fitzgerald -
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September 30, 2011, at 03:11 AM by Scott Fitzgerald -
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September 23, 2010, at 09:42 PM by Christian Cerrito -
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September 23, 2010, at 09:42 PM by Christian Cerrito -
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## Smoothing

to:

### Smoothing

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to:

September 23, 2010, at 09:37 PM by Christian Cerrito -
September 17, 2010, at 06:23 PM by Tom Igoe -
Changed lines 5-6 from:

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.

to:

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.

Changed lines 29-32 from:

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.

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

to:

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.

Changed line 47 from:
• AnalogInOutSerial - read an analog pin, map the result, and use that data to dim or brighten an LED
to:
• AnalogInOutSerial - read an analog pin, map the result, and use that data to dim or brighten an LED
September 16, 2010, at 10:09 PM by Tom Igoe -
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August 26, 2010, at 09:05 AM by Christian Cerrito -
Deleted line 48:
August 26, 2010, at 09:04 AM by Christian Cerrito -
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• [[Reference/serial]()
to:
August 26, 2010, at 09:03 AM by Christian Cerrito -
Changed lines 31-32 from:

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

to:

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

Changed lines 37-51 from:
to:
August 26, 2010, at 08:59 AM by Christian Cerrito -
Changed lines 29-30 from:

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.

to:

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.

August 26, 2010, at 08:53 AM by Christian Cerrito -
Changed lines 29-30 from:

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.

to:

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.

August 26, 2010, at 08:52 AM by Christian Cerrito -

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.

August 26, 2010, at 08:46 AM by Christian Cerrito -
Changed line 7 from:

'Hardware

to:

Hardware

August 26, 2010, at 08:46 AM by Christian Cerrito -
Changed lines 5-6 from:

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

to:

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
Deleted lines 12-13:

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to:

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

August 24, 2010, at 08:20 AM by Christian Cerrito -
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February 23, 2010, at 07:59 PM by Tom Igoe -
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``` /*
```
to:
Deleted lines 27-89:
```   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:
```

```   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.
```

``` 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:
}
```

``` void loop() {
// advance to the next position in the array:
index = index + 1;
```

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

```   // calculate the average:
// send it to the computer (as ASCII digits)
Serial.println(average, DEC);
}
```

August 27, 2009, at 08:46 PM by Tom Igoe -

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

July 05, 2009, at 07:22 PM by Tom Igoe -
Changed lines 21-29 from:

[@ /*

```  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.
```
to:
Changed lines 23-77 from:
```  The circuit:
```

```  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:
```

}

void loop() {

```  // subtract the last reading:
// advance to the next position in the array:
index = index + 1;
```

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

```  // calculate the average:
// send it to the computer (as ASCII digits)
Serial.println(average, DEC);
```

} @]

to:
June 25, 2009, at 11:29 PM by Tom Igoe -

click the image to enlarge

### Schematic

click the image to enlarge

June 17, 2009, at 11:30 PM by Tom Igoe -

/*

```  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:
```

```  Created 22 April 2007
By David A. Mellis  <dam@mellis.org>
```

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

• /

Changed line 36 from:

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

to:

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

Changed lines 38-44 from:

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

to:

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

Changed lines 49-51 from:
```  Serial.begin(9600);                     // initialize serial communication with computer
for (int i = 0; i < NUMREADINGS; i++)
```
to:
```  // initialize serial communication with computer:
Serial.begin(9600);
// initialize all the readings to 0:
```
Changed lines 56-67 from:

void loop() {

```  total -= readings[index];               // subtract the last reading
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
Serial.println(average);                // send it to the computer (as ASCII digits)
```
to:

void loop() {

```  // subtract the last reading:
// advance to the next position in the array:
index = index + 1;
```

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

```  // calculate the average:
// send it to the computer (as ASCII digits)
Serial.println(average, DEC);
```
April 22, 2007, at 07:19 PM by David A. Mellis -
Changed lines 5-6 from:

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

to:

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

Changed lines 9-10 from:

to:

Deleted lines 13-22:

/*

``` * Smoothing
* David A. Mellis <dam@mellis.org>
*
* and outputting it to an analog output.
*
* http://www.arduino.cc/en/Tutorial/Smoothing
*/
```
Changed lines 26-27 from:

int outputPin = 9;

to:
```  Serial.begin(9600);                     // initialize serial communication with computer
```
Changed line 45 from:
```  analogWrite(outputPin, average / 4);    // analog inputs go up to 1023, outputs to 255
```
to:
```  Serial.println(average);                // send it to the computer (as ASCII digits)
```
March 25, 2007, at 10:02 AM by David A. Mellis -

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.

### Code

Changed lines 14-22 from:
1. define NUMSAMPLES 10

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

int sensor = 0; int actuator = 9;

to:

/*

``` * Smoothing
* David A. Mellis <dam@mellis.org>
*
* 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.

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;

Changed lines 40-41 from:
```  for (int i = 0; i < NUMSAMPLES; i++)
samples[i] = 0;
```
to:
```  for (int i = 0; i < NUMREADINGS; i++)
```
Changed lines 46-50 from:
```  total -= samples[index];
total += samples[index];
index = (index + 1) % NUMSAMPLES;
analogWrite(actuator, total / NUMSAMPLES);
```
to:
```  total -= readings[index];               // subtract the last reading
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
```
January 14, 2007, at 03:28 PM by David A. Mellis -

[@

@]

January 14, 2007, at 03:28 PM by David A. Mellis -
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];