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// Six of the Arduino Digital Pins can be used as PWM (pulse width modulation)
// outputs (D3, D5, D6, D9, D10 and D11). PWM works by varying the ON duty cycle
// of a square wave output. This control feature is very useful for the control
// of many devices, such as with the L293D H-Bridge as a variable motor speed
// control. In this example, we will use the PWM output directly with an LED to
// control its brightness. The PWM feature is accessed with the
// analogWrite () function - where a value of 1023 will result in a 100% duty
// cycle, a value of 511 in a 50% duty cycle, and a value of 0 in a 0% duty cycle.
// In this tutorial, we will use the same circuit as in the Analog Input with a
// Potentiometer tutorial, only shifting the code to control the LED by dimming
// rather than varying its flash rate.
int potPIN = 0; // select the input pin for the potentiometer
int ledPIN = 9; // select the output pin for the LED
int potVAL = 0; // variable to store the value coming from the potentiometer
void setup() {
Serial.begin(9600); // set the baud rate for the serial window
pinMode(ledPIN, OUTPUT); // declare the ledPin as an OUTPUT, ANALOG IN is an
// input by default
}
void loop() {
potVAL = analogRead(potPIN); // read the value from the potentiometer
potVAL = (potVAL/4+10); // scale and shift the potVAL to be a useful
// input for setting the PWM duty cycle
analogWrite(ledPIN, potVAL); // output a square wave with proper duty cycle
// to brighten and dim LED based on putVal input
Serial.println(potVAL); // print potVAL in the arduino serial window
}