How to get LED to fade/ease in and out of color, rather than just "appear/disappear"?

Finz23

Just needed help adjusting my processing code to make the LED fade in and out of color (or ease in/out), rather than just "appear/disappear". Here is a snippet of code for when the LED on pin9 activates in response to certain sound pitch range (f) being detected:

  if(f > 175  && f < 237) {
  background(255,0,0);
  arduino.analogWrite(9, 255);
  }

cheers!

fuzzySi

It needs to be on a PWM pin - depends on which arduino you're using but pin 9 not usually PWM.

https://www.arduino.cc/en/Reference/AnalogWrite

Finz23

it is on a pwm pin, I am pretty sure anyway. I ran a sample pwm sketch and the LED wored fine. I am using the Uno model. Regardless, lets just assume I am using the right pin. What would the code be?

fuzzySi

This gives you a sawtooth value - just use value of LFO ie (analogWrite 9, LFO);

    // this makes a sawtooth wave

    float LFO = 0; // starting value
    float dLFO = 3; // delta LFO ie speed of change 

    void setup() {
    }

    void draw() { 
      LFO += dLFO; 
      if ((LFO <= 0) || (LFO >= 255)) { // if out of bounds
        dLFO = - dLFO; // swap direction
      }
      println(LFO);

Finz23

Much appreciated! Going to test it out when I get home. Thank you