Thursday, June 1, 2017

NodeMCU/ESP8266 Arduino Core analog output PWM

Example of NodeMCU with ESP8266 Arduino Core to output PWM by calling analogWrite(), to control brightness of RGB LED.



NodeMCU_PWM.inf
int ledB = D0;
int ledG = D1;
int ledR = D2;

void setup() {
  pinMode(D0, OUTPUT);
  pinMode(D1, OUTPUT);
  pinMode(D2, OUTPUT);
  //Set PWM frequency 500, default is 1000
  //Set range 0~100, default is 0~1023
  analogWriteFreq(500);
  analogWriteRange(100);
}

// the loop function runs over and over again forever
void loop() {
  analogWrite(ledR, 0);
  analogWrite(ledG, 0);
  analogWrite(ledB, 0);
  delay(500);
  analogWrite(ledR, 100);
  analogWrite(ledG, 100);
  analogWrite(ledB, 100);
  delay(500);
  analogWrite(ledR, 0);
  analogWrite(ledG, 0);
  analogWrite(ledB, 0);
  delay(500);

  int i;
  for(i=0; i<100; i++){
    analogWrite(ledR, i);
    delay(10);
  }
  analogWrite(ledR, 0);
  
  for(i=0; i<100; i++){
    analogWrite(ledG, i);
    delay(10);
  }
  analogWrite(ledG, 0);
  
  for(i=0; i<100; i++){
    analogWrite(ledB, i);
    delay(10);
  }
  analogWrite(ledB, 0);

  for(i=0; i<100; i++8){
    analogWrite(ledR, i);
    analogWrite(ledG, i);
    analogWrite(ledB, i);
    delay(10);
  }

  for(i=100; i>0; i--){
    analogWrite(ledR, i);
    analogWrite(ledG, i);
    analogWrite(ledB, i);
    delay(10);
  }

}

Reference:
analogWrite(pin, value) enables software PWM on the given pin. PWM may be used on pins 0 to 16. Call analogWrite(pin, 0) to disable PWM on the pin. value may be in range from 0 to PWMRANGE, which is equal to 1023 by default. PWM range may be changed by calling analogWriteRange(new_range).

PWM frequency is 1kHz by default. Call analogWriteFreq(new_frequency) to change the frequency.

Next:
simple http server to output PWM, to control color/brightness of RGB LED.


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