Replace delayMicroseconds() with micros()

Hello everyone!

I’m trying to make an AC control for lamps. There is a zero crossing detector that sends a pulse to Arduino everytime the sine wave passes thru 0. This pulse activate an ISR that generates another phased pulse to trigger the TRIAC. In near future, I will add other lamps that will be controlled separately with potentiometers. The delayMicroseconds() won’t let me control multiple lamps, so I want to replace it with micros() (code below). I need to get rid off delays cuz the readings can’t be late. I need simultaneously readings from multiple potentiometers.

  • The code is working perfectly with one lamp/pot. I haven’t tested with more lamps yet.

  • Graphs: [Attached images]
    blue line: zero-cross signal
    red line: dimmerized signal (phased signal)
    green line: load sine wave


#define dimmer 5

volatile long pot = 0.0; // potentiometer read

void zeroCross() {

    // Calculates t1
  long t1 = 8333L * (100L - pot) / 100L;

void setup() {
  pinMode(dimmer, OUTPUT);
  digitalWrite(dimmer, LOW);
  attachInterrupt(0, zeroCross, FALLING);

void loop() {
  pot = map(analogRead(A0), 0, 1023, 1, 90);


Just use this and replace millis() with micros().

Just keep in mind that the Arduino micros() resolution is 4 microseconds and overflows every 70 minutes.

The ESP32's equivalent of micros resolution is 1 microsecond and overflows in a bit more then 100 years. Then again you'd not need micros() with a ESP32. The OS, freeRTOS, built into the ESP32 is multitasking and multithreading.

Disparaging posts REMOVED.


Could you use code tags please ( </> )

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