I am working on a project that I am supplying with voltage an LED through a digital pin (26) and I want the LED to be switched off after 4 seconds.

I am using Arduino Mega2560 and I am programming it using Arduino's IDE version 1.6.10. I have installed the SimpleTimer library .zip method but it does not seem to function.


#include <SimpleTimer.h>

SimpleTimer timer;

void setup() {
pinMode(26, OUTPUT);
digitalWrite(26, HIGH);

timerId = timer.setTimeout(4000, switchOff);

void switchOff() {
  digitalWrite(26, LOW);

void loop() {

The problem is that the LED stays just on (digitalWrite(26, HIGH);) instead of going to the switchOff function and turning off (digitalWrite(26, LOW);). I have also tried using Timer1 and Timer libraries but they also do not work. Can someone who has made any of the libraries work, provide me with some guidance?

  • You have to call timer.run() inside loop function.
    – Gerben
    Aug 20, 2016 at 17:52
  • It worked! Answer the question and I will choose your answer as the best one.
    – vchan
    Aug 20, 2016 at 18:47

1 Answer 1


You have to call timer.run() inside loop function.

The SimpleTimer library is more like a scheduler. You call at every so often, and it checks if there is any event that has expired.

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