// PWM, variation en douceur d'une LED

/* La valeur du PWM s'étend sur 256 paliers, de 0 (=0%) à 255 (=100%). 
On peut ainsi définir la valeur PWM souhaitée avec la formule suivante:
𝑉𝑎𝑙𝑒𝑢𝑟 𝑃𝑊𝑀 = (Pourcentage souhaité / 100) x 255 
𝑉𝑎𝑙𝑒𝑢𝑟 𝑒𝑛 % =  (valeur PWM / 255) X 100
*/

// déclarations
int led_R = 3;    // renomme la broche 3 en led_R
int timer = 100;  // Durée de 100ms ou 0,1 seconde

// initialisation
void setup() {
pinMode(led_R, OUTPUT);
}

void loop() {                      /* Pourcentage de luminosité
                                          VV  */
analogWrite(led_R,0); delay(timer/2);   //0%
analogWrite(led_R,25.5); delay(timer);  //10%
analogWrite(led_R,51); delay(timer);    //20%
analogWrite(led_R,76.5); delay(timer);  //30%
analogWrite(led_R,102); delay(timer);   //40%
analogWrite(led_R,127.5); delay(timer); //50%
analogWrite(led_R,153); delay(timer);   //60%
analogWrite(led_R,178.5); delay(timer); //70%
analogWrite(led_R,204); delay(timer);   //80%
analogWrite(led_R,229.5); delay(timer); //90%
analogWrite(led_R,255); delay(timer);   //100%
analogWrite(led_R,229.5); delay(timer); //90%
analogWrite(led_R,204); delay(timer);   //80%
analogWrite(led_R,178.5); delay(timer); //70%
analogWrite(led_R,153); delay(timer);   //60%
analogWrite(led_R,127.5); delay(timer); //50%
analogWrite(led_R,102); delay(timer);   //40%
analogWrite(led_R,76.5); delay(timer);  //30%
analogWrite(led_R,51); delay(timer);    //20%
analogWrite(led_R,25.5); delay(timer);  //10%
analogWrite(led_R,0); delay(timer/2);   //0%

}