Tutorial.PWM History

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June 07, 2010, at 12:39 AM by Equipo Traduccion -
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Una vez cargado y ejecutado el ejemplo mueve la arduino de un lado a otro, lo que ves es esencialmente un mapeado del tiempo a lo largo del espacio. A nuestros ojos el movimiento desdibuja cada parpadeo del LED en una linea. A medida que la luminosidad del LED se incrementa o atenua esas pequeñas lineas crecen o se reducen. Ahora estas viendo el ancho de pulso (pulse width).

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Once you get this example running, grab your arduino and shake it back and forth. What you are doing here is essentially mapping time across the space. To our eyes, the movement blurs each LED blink into a line. As the LED fades in and out, those little lines will grow and shrink in length. Now you are seeing the pulse width.

to:

Una vez cargado y ejecutado el ejemplo mueve la arduino de un lado a otro, lo que ves es esencialmente un mapeado del tiempo a lo largo del espacio. A nuestros ojos el movimiento difumina cada parpadeo del LED en una linea. A medida que la luminosidad del LED se incrementa o atenua esas pequeñas lineas crecen o se reducen. Ahora estas viendo el ancho de pulso (pulse width).

June 07, 2010, at 12:03 AM by Equipo Traduccion -
Changed lines 13-19 from:

pendiente de traducción:

to:

pendiente de mejorar la traducción:

Una vez cargado y ejecutado el ejemplo mueve la arduino de un lado a otro, lo que ves es esencialmente un mapeado del tiempo a lo largo del espacio. A nuestros ojos el movimiento desdibuja cada parpadeo del LED en una linea. A medida que la luminosidad del LED se incrementa o atenua esas pequeñas lineas crecen o se reducen. Ahora estas viendo el ancho de pulso (pulse width).

Texto original:

June 06, 2010, at 11:57 PM by Equipo Traduccion -
Changed lines 3-8 from:

The Fading example demonstrates the use of analog output (PWM) to fade an LED. It is available in the File->Sketchbook->Examples->Analog menu of the Arduino software.

Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off. This on-off pattern can simulate voltages in between full on (5 Volts) and off (0 Volts) by changing the portion of the time the signal spends on versus the time that the signal spends off. The duration of "on time" is called the pulse width. To get varying analog values, you change, or modulate, that pulse width. If you repeat this on-off pattern fast enough with an LED for example, the result is as if the signal is a steady voltage between 0 and 5v controlling the brightness of the LED.

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogWrite() is on a scale of 0 - 255, such that analogWrite(255) requests a 100% duty cycle (always on), and analogWrite(127) is a 50% duty cycle (on half the time) for example.

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El ejemplo "Fading" demuestra el uso de una salida analógica (PWM) para atenuar y aumentar la luminosidad de un LED. Lo tienes disponible en la opción "File->Sketchbook->Examples->Analog" del menú del software de Arduino.

La Modulación por Ancho de Pulso (PWM = Pulse Width Modulation) es una tecnica para simular una salida analógica con una salida digital. El control digital se usa para crear una onda cuadrada, una señal que conmuta constantemente entre encendido y apagado. Este patron de encendido-apagado puede simular voltajes entre 0 (siempre apagado) y 5 voltios (siempre encendido) simplemente variando la proporción de tiempo entre encendido y apagado. A la duración del tiempo de encendido (ON) se le llama Ancho de Pulso (pulse width). Para variar el valor analógico cambiamos, o modulamos, ese ancho de pulso. Si repetimos este patrón de encendido-apagado lo suficientemente rapido por ejemplo con un LED el resultado es como si la señal variara entre 0 y 5 voltios controlando el brillo del LED.

En el grafico de abajo las lineas verdes representan un periodo regular. Esta duración o periodo es la inversa de la frecuencia del PWM. En otras palabras, con la Arduino la frecuencia PWM es bastante proxima a 500Hz lo que equivale a periodos de 2 milisegundos cada uno. La llamada a la función analogWrite() debe ser en la escala desde 0 a 255, siendo 255 el 100% de ciclo (siempre encendido), el valor 127 será el 50% del ciclo (la mitad del tiempo encendido), etc.

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pendiente de traducción:

April 10, 2008, at 04:53 PM by David A. Mellis -
Changed lines 7-8 from:

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogWrite() is on a scale of 0 - 255, such that analogWrite(9, 255) requests a 100% duty cycle (always on), and analogWrite(9, 127) is a 50% duty cycle (on half the time) for example.

to:

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogWrite() is on a scale of 0 - 255, such that analogWrite(255) requests a 100% duty cycle (always on), and analogWrite(127) is a 50% duty cycle (on half the time) for example.

April 10, 2008, at 04:52 PM by David A. Mellis -
Changed lines 7-8 from:

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's analogOut PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogOut is on a scale of 0 - 255, such that analogOut(255) requests a 100% duty cycle (always on), and analogOut(127) is a 50% duty cycle (on half the time) for example.

to:

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogWrite() is on a scale of 0 - 255, such that analogWrite(9, 255) requests a 100% duty cycle (always on), and analogWrite(9, 127) is a 50% duty cycle (on half the time) for example.

April 10, 2008, at 04:43 PM by David A. Mellis -
Added lines 13-14:

Written by Timothy Hirzel

April 10, 2008, at 04:42 PM by David A. Mellis -
Added lines 1-13:

PWM

The Fading example demonstrates the use of analog output (PWM) to fade an LED. It is available in the File->Sketchbook->Examples->Analog menu of the Arduino software.

Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off. This on-off pattern can simulate voltages in between full on (5 Volts) and off (0 Volts) by changing the portion of the time the signal spends on versus the time that the signal spends off. The duration of "on time" is called the pulse width. To get varying analog values, you change, or modulate, that pulse width. If you repeat this on-off pattern fast enough with an LED for example, the result is as if the signal is a steady voltage between 0 and 5v controlling the brightness of the LED.

In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's analogOut PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each. A call to analogOut is on a scale of 0 - 255, such that analogOut(255) requests a 100% duty cycle (always on), and analogOut(127) is a 50% duty cycle (on half the time) for example.

Once you get this example running, grab your arduino and shake it back and forth. What you are doing here is essentially mapping time across the space. To our eyes, the movement blurs each LED blink into a line. As the LED fades in and out, those little lines will grow and shrink in length. Now you are seeing the pulse width.

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