Pulse Width Modulation at last! In our last example, we read a potentiometer (pot) to get a analog value of 0-1023, and used that number to delay the digital on and off times of a LED. This example will do the same read, but output a analog value (PWM) of 0-255 to control the brightness of a LED. It’s still controlling the on and off times, but so quickly the eye doesn’t see off, it just sees decreased or increased brightness. this is much more power efficient than using a resistor to shed voltage, dimming a bulb. We will use this same method in an upcoming post to control the speed of a motor.
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(video uploaded to youtube)
int sensorPin = A0; // Analog input pin to pot int ledPin = 7; // PWM pin to LED int sensorValue = 0; // variable to store pot value
void setup() {}
void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
// converts 0-1023 to 0-255
sensorValue /=4;
// outputs PWM signal to LED
analogWrite(ledPin, sensorValue);
}