LED on/off

Projects Programming
3

This code will turn on LED on pin 13 on positive period and turn off LED on negative period.
Hope it helps.

#include <Arduino.h>
 
int led = 13;
float wave = 0;
int step = 0; // 0 - 360 degrees
bool led13 = false; // Value of LED ON/OFF

void setup() {                
  pinMode(led, OUTPUT);     
}

// the loop routine runs over and over again forever:
void loop() {
  // Calculate sine value of 
  wave = sin(step * DEG_TO_RAD);

  // Turn on LED on first step of positive period
  if (wave > 0 && !led13)
  {
    digitalWrite(led, HIGH);
    led13 = true;
  }
  // Turn off LED on first step of negative period
  else if (wave < 0 && led13)
  {
    digitalWrite(led, LOW);
    led13 = false;
  }

  // Reset step
  if (step++ > 360)
  {
    step = 0;
  }

  delay(5);
}

/Mogens