Analog Write

Lesson 8- LED Fade

 While the Arduino Uno cannot output a continuously varying(analog) voltage, it can simulate this using analogWrite

for example:

analogWrite(3, 128); //sets pin 3 to half-brightness.

int led = 9; // the PWM pin the LED is attached to

int brightness = 0; // how bright the LED is

int fadeAmount = 5; // how many points to fade the LED by

// the setup routine runs once when you press reset:

void setup() {

// declare pin 9 to be an output:

pinMode(led, OUTPUT);

}

// the loop routine runs over and over again forever:

void loop() {

// set the brightness of pin 9:

analogWrite(led, brightness);

// change the brightness for next time through the loop:

brightness = brightness + fadeAmount;

// reverse the direction of the fading at the ends of the fade:

if (brightness <= 0 || brightness >= 255) {

fadeAmount = -fadeAmount;

}

// wait for 30 milliseconds to see the dimming effect

delay(30);

}

Related:

Substitute a DC Motor for the LED- Knob controls the motor speed

// the setup routine runs once when you press reset:

int motorPin = 12;

void setup() {

// initialize serial communication at 9600 bits per second:

Serial.begin(9600);

}

void loop() 

{

int sensorValue = analogRead(A0);// read the input on analog pin 0:

analogWrite(motorPin, sensorValue / 4);//analog out is 0 to 1053; 

//analogWrite is 0 to 255

}